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  • Problem adding subviews (UIButtons) to subclass of UIImageView

    - by samfu_1
    I'm adding a custom button/keypad to my application. Thus far, I have a UIImageView subclass that contains an animation that slides it from the bottom of the screen, and then back down when the user no longer needs it. I'm having trouble adding UIButtons to this UIImageView, however. Since this is a subclass of UIView, I'm attempting to add buttons to my view via the initWithFrame: method. (slideDown method is the added animation) in my UIImageView Subclass, I have a UIButton ivar object added: -(id)initWithFrame:(CGRect)frame { if (self = [super initWithFrame: frame]) { UIButton *button = [UIButton buttonWithType: UIButtonTypeRoundedRect]; button.frame = CGRectMake(16.0, 20.0, 50.0, 50.0); [button setTitle: @"Go" forState: UIControlStateNormal]; [button addTarget: self action: @selector(slideDown) forControlEvents: UIControlEventTouchUpInside]; self.button1 = button; [self addSubview: button1]; NSLog(@"Button added"); } return self; } In my view controller, I instantiate my UIIMageView Subclass in the -(void)viewDidLoad: method as follows: -(void)viewDidLoad { //other objects init'ed ButtonPad *customPad = [[ButtonPad alloc] initWithImage: [UIImage imageNamed: @"ButtonPad.png"]]; customPad.frame = CGRectMake(0.0, 480.0, 320.0, 300.0); self.buttonPad = customPad; [self.view addSubview: buttonPad]; [customPad release]; [super viewDidLoad]; } My current app allows the view to slide up and down off of the screen without any problems. However, the button never appears. I have also tried adding the button to my buttonPad object by instantiating & adding it as a subView to the buttonPad in my view controller file. This worked... but it didn't allow the button to function. I am wondering: A.) Is it appropriate to add buttons or any subview for that matter to the UIView initWithFrame: method or should I be adding these subviews as a subview to my buttonPad in the view Controller file? B.) Since I am creating a custom button/keypad, am i following a valid approach by using a normal UIViewController or should I be using something like a modal view Controller? ( I have little knowledge about these.)

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  • Android App to call a number on button click

    - by FosterZ
    hey guys this is my 1st android app(learning), so i want to call a number given in the textbox but i'm getting error as "The application 'xyz'(process com.adroid) has stoped unexpectedly".. following the code i have done so far... where m doing wrong ?? EditText txtPhn; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); Button callButton = (Button)findViewById(R.id.btnCall); txtPhn = (EditText)findViewById(R.id.txtPhnNumber); callButton.setOnClickListener(new OnClickListener() { public void onClick(View v) { try { Intent callIntent = new Intent(Intent.ACTION_CALL); callIntent.setData(Uri.parse("tel:"+txtPhn.getText().toString())); startActivity(callIntent); } catch (ActivityNotFoundException activityException) { Log.e("Calling a Phone Number", "Call failed", activityException); } } }); } EDITED LogCat 03-09 11:23:25.874: ERROR/AndroidRuntime(370): FATAL EXCEPTION: main 03-09 11:23:25.874: ERROR/AndroidRuntime(370): java.lang.SecurityException: Permission Denial: starting Intent { act=android.intent.action.CALL dat=tel:xxx-xxx-xxxx flg=0x10000000 cmp=com.android.phone/.OutgoingCallBroadcaster } from ProcessRecord{40738d70 370:org.krish.android/10034} (pid=370, uid=10034) requires android.permission.CALL_PHONE 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at android.os.Parcel.readException(Parcel.java:1322) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at android.os.Parcel.readException(Parcel.java:1276) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at android.app.ActivityManagerProxy.startActivity(ActivityManagerNative.java:1351) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at android.app.Instrumentation.execStartActivity(Instrumentation.java:1374) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at android.app.Activity.startActivityForResult(Activity.java:2827) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at android.app.Activity.startActivity(Activity.java:2933) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at org.krish.android.caller$1.onClick(caller.java:29) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at android.view.View.performClick(View.java:2485) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at android.view.View$PerformClick.run(View.java:9080) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at android.os.Handler.handleCallback(Handler.java:587) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at android.os.Handler.dispatchMessage(Handler.java:92) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at android.os.Looper.loop(Looper.java:123) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at android.app.ActivityThread.main(ActivityThread.java:3683) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at java.lang.reflect.Method.invokeNative(Native Method) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at java.lang.reflect.Method.invoke(Method.java:507) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 03-09 11:23:25.874: ERROR/AndroidRuntime(370): at dalvik.system.NativeStart.main(Native Method)

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  • Advice on displaying and allowing editing of data using ASP.NET MVC?

    - by Remnant
    I am embarking upon my first ASP.NET MVC project and I would like to get some input on possible ways to display database data and general best practice. In short, the body of my webpage will show data from my database in a table like format, with each table row showing similar data. For example: Name Age Position Date Joined Jon Smith 23 Striker 18th Mar 2005 John Doe 38 Defender 3rd Jan 1988 In terms of functionality, primarily I’d like to give the user the ability to edit the data and, after the edit, commit the edit to the database and refresh the view.The reason I want to refresh the view is because the data is date ordered and I will need to re-sort if the user edits a date field. My main question is what architecture / tools would be best suited to this fulfil my requirements at a high level? From the research I have done so far my initial conclusions were: ADO.NET for data retrieval. This is something I have used before and feel comfortable with. I like the look of LINQ to SQL but don’t want to make the learning curve any steeper for my first outing into MVC land just yet. Partial Views to create a template and then iterate through a datatable that I have pulled back from my database model. jQuery to allow the user to edit data in the table, error check edited data entries etc. Also, my intial view was that caching the data would not be a key requirement here. The only field a user will be able to update is the field and, if they do, I will need to commit that data to the database immediately and then refresh the view (as the data is date sorted). Any thoughts on this? Alternatively, I have seen some jQuery plug-ins that emulate a datagrid and provide associated functionality. My first thoughts are that I do not need all the functionality that comes with these plug-ins (e.g. zebra striping, ability to sort by column using sort glyph in column headers etc .) and I don’t really see any benefit to this over and above the solution I have outlined above. Again, is there reason to reconsider this view? Finally, when a user edits a date , I will need to refresh the view. In order to do this I had been reading about Html.RenderAction and this seemed like it may be a better option than using Partial Views as I can incorporate application logic into the action method. Am I right to consider Html.RenderAction or have I misunderstood its usage? Hope this post is clear and not too long. I did consider separate posts for each topic (e.g. Partial View vs. Html.RenderAction, when to use jQury datagrid plug-in) but it feels like these issues are so intertwined that they need to be dealt with in contect of each other. Thanks

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  • NSCollectionView draws nothing

    - by PCWiz
    I'm trying to set up an NSCollectionView (I have done this successfully in the past, but for some reason it fails this time). I have a model class called "TestModel", and it has an NSString property that just returns a string (just for testing purposes right now). I then have an NSMutableArray property declaration in my main app delegate class, and to this array I add instances of the TestModel object. I then have an Array Controller that has its Content Array bound the app delegate's NSMutableArray. I can confirm that everything up to here is working fine; NSLogging: [[[arrayController arrangedObjects] objectAtIndex:0] teststring] worked fine. I then have all the appropriate bindings for the collection view set up, (itemPrototype and content), and for the Collection View Item (view). I then have a text field in the collection item view that is bound to Collection View Item.representedObject.teststring. However NOTHING displays in the collection view when I start the app, just a blank white screen. What am I missing? UPDATE: Here is the code I use (requested by wil shipley): // App delegate class @interface AppController : NSObject { NSMutableArray *objectArray; } @property (readwrite, retain) NSMutableArray *objectArray; @end @implementation AppController @synthesize objectArray; - (id)init { if (self = [super init]) { objectArray = [[NSMutableArray alloc] init]; } return self; } - (void)applicationDidFinishLaunching:(NSNotification *)aNotification { TestModel *test = [[[TestModel alloc] initWithString:@"somerandomstring"] autorelease]; if (test) [objectArray addObject:test]; } @end // The model class (TestModel) @interface TestModel : NSObject { NSString *teststring; } @property (readwrite, retain) NSString *teststring; - (id)initWithString:(NSString*)customString; @end @implementation TestModel @synthesize teststring; - (id)initWithString:(NSString*)customString { [self setTeststring:customString]; } - (void)dealloc { [teststring release]; } @end And then like I said the content array of the Array Controller is bound to this "objectArray", and the Content of the NSCollectionView is bound to Array Controller.arrangedObjects. I can verify that the Array Controller has the objects in it by NSLogging [arrayController arrangedObjects], and it returns the correct object. Its just that nothing displays in the NSCollectionView. UPDATE 2: If I log [collectionView content] I get nothing: 2009-10-21 08:02:42.385 CollViewTest[743:a0f] ( ) The problem is probably there. UPDATE 3: As requested here is the Xcode project: http://www.mediafire.com/?mjgdzgjjfzw Its a menubar app, so it has no window. When you build and run the app you'll see a menubar item that says "test", this opens the view that contains the NSCollectionView. Thanks

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  • TVirtualStringTree - resetting non-visual nodes and memory comsumption

    - by Remy Lebeau - TeamB
    I have an app that loads records from a binary log file and displays them in a virtual TListView. There are potentially millions of records in a file, and the display can be filtered by the user, so I do not load all of the records in memory at one time, and the ListView item indexes are not a 1-to-1 relation with the file record offsets (List item 1 may be file record 100, for instance). I use the ListView's OnDataHint event to load records for just the items the ListView is actually interested in. As the user scrolls around, the range specified by OnDataHint changes, allowing me to free records that are not in the new range, and allocate new records as needed. This works fine, speed is tolerable, and the memory footprint is very low. I am currently evaluating TVirtualStringTree as a replacement for the TListView, mainly because I want to add the ability to expand/collapse records that span multiple lines (I can fudge it with the TListView by incrementing/decrementing the item count dynamically, but this is not as straight forward as using a real tree). For the most part, I have been able to port the TListView logic and have everything work as I need. I notice that TVirtualStringTree's virtual paridigm is vastly different, though. It does not have the same kind of OnDataHint functionality that TListView does (I can use the OnScroll event to fake it, which allows my memory buffer logic to continue working), and I can use the OnInitializeNode event to associate nodes with records that are allocated. However, once a tree node is initialized, it sees that it remains initialized for the lifetime of the tree. That is not good for me. As the user scrolls around and I remove records from memory, I need to reset those non-visual nodes without removing them from the tree completely, or losing their expand/collapse states. When the user scrolls them back into view, I can re-allocate the records and re-initialize the nodes. Basically, I want to make TVirtualStringTree act as much like TListView as possible, as far as its virtualization is concerned. I have seen that TVirtualStringTree has a ResetNode() method, but I encounter various errors whenever I try to use it. I must be using it wrong. I also thought of just storing a data pointer inside each node to my record buffers, and I allocate and free memory, update those pointers accordingly. The end effect does not work so well, either. Worse, my largest test log file has ~5 million records in it. If I initialize the TVirtualStringTree with that many nodes at one time (when the log display is unfiltered), the tree's internal overhead for its nodes takes up a whopping 260MB of memory (without any records being allocated yet). Whereas with the TListView, loading the same log file and all the memory logic behind it, I can get away with using just a few MBs. Any ideas?

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  • How can the DataView object reference not be set?

    - by dboarman-FissureStudios
    I have the following sample where the SourceData class would represent a DataView resulting from an Sql query: class MainClass { private static SourceData Source; private static DataView View; private static DataView Destination; public static void Main (string[] args) { Source = new SourceData(); View = new DataView(Source.Table); Destination = new DataView(); Source.AddRowData("Table1", 100); Source.AddRowData("Table2", 1500); Source.AddRowData("Table3", 1300324); Source.AddRowData("Table4", 1122494); Source.AddRowData("Table5", 132545); Console.WriteLine(String.Format("Data View Records: {0}", View.Count)); foreach(DataRowView drvRow in View) { Console.WriteLine(String.Format("Source {0} has {1} records.", drvRow["table"], drvRow["records"])); DataRowView newRow = Destination.AddNew(); newRow["table"] = drvRow["table"]; newRow["records"] = drvRow["records"]; } Console.WriteLine(); Console.WriteLine(String.Format("Destination View Records: {0}", Destination.Count)); foreach(DataRowView drvRow in Destination) { Console.WriteLine(String.Format("Destination {0} has {1} records.", drvRow["table"], drvRow["records"])); } } } class SourceData { public DataTable Table { get{return dataTable;} } private DataTable dataTable; public SourceData() { dataTable = new DataTable("TestTable"); dataTable.Columns.Add("table", typeof(string)); dataTable.Columns.Add("records", typeof(int)); } public void AddRowData(string tableName, int tableRows) { dataTable.Rows.Add(tableName, tableRows); } } My output is: Data View Records: 5 Source Table1 has 100 records. Unhandled Exception: System.NullReferenceException: Object reference not set to an instance of an object at System.Data.DataView.AddNew () [0x0003e] in /usr/src/packages/BUILD/mono-2.4.2.3 /mcs/class/System.Data/System.Data/DataView.cs:344 at DataViewTest.MainClass.Main (System.String[] args) [0x000e8] in /home/david/Projects/DataViewTest/SourceData.cs:29 I did some reading here: DataView:AddNew Method... ...and it would appear that I am doing this the right way. How come I am getting the Object reference not set?

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  • Have problems designing input and output for a calculator app

    - by zoul
    Hello! I am writing a button calculator. I have the code split into model, view and a controller. The model knows nothing about formatting, it is only concerned with numbers. All formatting is done in the view. The model gets its input as keypresses, each keypress is a part of an enum: typedef enum { kButtonUnknown = 0, kButtonMemoryClear = 100, kButtonMemoryPlus = 112, kButtonMemoryMinus = 109, kButtonMemoryRecall = 114, kButtonClear = 99, … }; When the user presses a button (say 1), the model receives a button code (kButtonNum1), adds the corresponding number to a string input buffer ("1") and updates the numeric output value (1.0). The controller then passes the numeric output value to the view that formats it (1). This is all plain, simple and clean, but does not really work. The problem is that when user enters a part of a number (say 0.00, going to enter 0.001), the input does not survive the way through model to view and the display says 0 instead of 0.00. I know why this happens ("0.00"::string parses to 0::double and that gets formatted as 0). What I don’t know is how to design the calculator so that the code stays clean and simple and the numbers will show up on screen exactly as the user types them. I’ve already come with some kind of solution, but that’s essentially a hack and breaks the beautiful and simple flow from the calculator model to the display. Ideas? Current solution keeps track of the calculator state. If the calculator is building a number, I take the calculator input buffer (a string) and directly set the display contents (also a string). Otherwise I take the proper path, ie. take the numeric calculator output, pass it to the view as a double and the view uses its internal formatter to create a string for the display. Example input: input | display | mode ------+---------+------------ 0 | 0 | from string 0. | 0. | from string 0.0 | 0.0 | from string 0.0+ | 0 | from number This is ugly. (1) The calculator has to expose its input buffer and state. (2) The view has to expose its display and allow setting its contents directly using a string. (3) I have to duplicate some of the formatting code to format the string I got from the calculator input buffer. If user enters 12345.000, I have to display 12,345.000 and therefore I’ve got to have a commification code for strings. Yuck.

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  • What's the best way to do base36 arithmetic in perl?

    - by DVK
    What's the best way to do base36 arithmetic in Perl? To be more specific, I need to be able to do the following: Operate on positive N-digit numbers in base 36 (e.g. digits are 0-9 A-Z) N is finite, say 9 Provide basic arithmetic, at the very least the following 3: Addition (A+B) Subtraction (A-B) Whole division, e.g. floor(A/B). Strictly speaking, I don't really need a base10 conversion ability - the numbers will 100% of time be in base36. So I'm quite OK if the solution does NOT implement conversion from base36 back to base10 and vice versa. I don't much care whether the solution is brute-force "convert to base 10 and back" or converting to binary, or some more elegant approach "natively" performing baseN operations (as stated above, to/from base10 conversion is not a requirement). My only 3 considerations are: It fits the minimum specifications above It's "standard". Currently we're using and old homegrown module based on base10 conversion done by hand that is buggy and sucks. I'd much rather replace that with some commonly used CPAN solution instead of re-writing my own bicycle from scratch, but I'm perfectly capable of building it if no better standard possibility exists. It must be fast-ish (though not lightning fast). Something that takes 1 second to sum up 2 9-digit base36 numbers is worse than anything I can roll on my own :) P.S. Just to provide some context in case people decide to solve my XY problem for me in addition to answering the technical question above :) We have a fairly large tree (stored in DB as a bunch of edges), and we need to superimpose order on a subset of that tree. The tree dimentions are big both depth- and breadth- wise. The tree is VERY actively updated (inserts and deletes and branch moves). This is currently done by having a second table with 3 columns: parent_vertex, child_vertex, local_order, where local_order is an 9-character string built of A-Z0-9 (e.g. base 36 number). Additional considerations: It is required that the local order is unique per child (and obviously unique per parent), Any complete re-ordering of a parent is somewhat expensive, and thus the implementation is to try and assign - for a parent with X children - the orders which are somewhat evenly distributed between 0 and 36**10-1, so that almost no tree inserts result in a full re-ordering.

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  • How to add Listview in tab activity?

    - by sandip armal
    I have one "SubjectTabActivity" and i need to show listview on this activity. But when i want to implement ListActivity it doesn't show listActivity. I have two(addchapter,addsubject) xml file with "SubjectTabActivity". and i need to show my database item il list view in respective xml file. but i don't understand how to do that? How to add Listactivity in TabActivity?. Please give me any reference or code. Thanks in advance.. Here is my reference code. public class MasterMainActivity extends TabActivity { LayoutInflater layoutInflater = null; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.master); Intent intent=getIntent(); setResult(RESULT_OK, intent); layoutInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); TabHost tabHost = getTabHost(); TabHost.TabSpec tab1spec = tabHost.newTabSpec("tabOneSpec"); ImageView imgView = new ImageView(this); imgView.setBackgroundResource(R.drawable.subject); tab1spec.setIndicator("Subject", imgView.getBackground()); tab1spec.setContent(new TabContentLayout()); TabHost.TabSpec tab2spec = tabHost.newTabSpec("tabTwoSpec"); tab2spec.setContent(new TabContentLayout()); ImageView imgView1 = new ImageView(this); imgView1.setBackgroundResource(R.drawable.chapter); tab2spec.setIndicator("Chapter", imgView1.getBackground()); tabHost.addTab(tab1spec); tabHost.addTab(tab2spec); } private class TabContentLayout implements TabHost.TabContentFactory { @Override public View createTabContent(String tag) { View view = null; if(tag.equals("tabOneSpec")) { try { //static final String[] FRUITS = new String[] { "Apple", "Avocado", "Banana", // "Blueberry", "Coconut", "Durian", "Guava", "Kiwifruit", //"Jackfruit", "Mango", "Olive", "Pear", "Sugar-apple" }; view = (LinearLayout) layoutInflater.inflate(R.layout.subjecttabview, null); //setListAdapter(new ArrayAdapter<String>(this, R.layout.subjecttabview,FRUITS)); } catch(Exception e) { e.printStackTrace(); } } if(tag.equals("tabTwoSpec")) { try { view = (LinearLayout) layoutInflater.inflate(R.layout.chaptertabview, null); } catch(Exception e) { e.printStackTrace(); } } return view; } } How to add ListActivity in this TabActivity

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  • How to generate and encode (for use in GA), random, strict, binary rooted trees with N leaves?

    - by Peter Simon
    First, I am an engineer, not a computer scientist, so I apologize in advance for any misuse of nomenclature and general ignorance of CS background. Here is the motivational background for my question: I am contemplating writing a genetic algorithm optimizer to aid in designing a power divider network (also called a beam forming network, or BFN for short). The BFN is intended to distribute power to each of N radiating elements in an array of antennas. The fraction of the total input power to be delivered to each radiating element has been specified. Topologically speaking, a BFN is a strictly binary, rooted tree. Each of the (N-1) interior nodes of the tree represents the input port of an unequal, binary power splitter. The N leaves of the tree are the power divider outputs. Given a particular power divider topology, one is still free to map the power divider outputs to the array inputs in an arbitrary order. There are N! such permutations of the outputs. There are several considerations in choosing the desired ordering: 1) The power ratio for each binary coupler should be within a specified range of values. 2) The ordering should be chosen to simplify the mechanical routing of the transmission lines connecting the power divider. The number of ouputs N of the BFN may range from, say, 6 to 22. I have already written a genetic algorithm optimizer that, given a particular BFN topology and desired array input power distribution, will search through the N! permutations of the BFN outputs to generate a design with compliant power ratios and good mechanical routing. I would now like to generalize my program to automatically generate and search through the space of possible BFN topologies. As I understand it, for N outputs (leaves of the binary tree), there are $C_{N-1}$ different topologies that can be constructed, where $C_N$ is the Catalan number. I would like to know how to encode an arbitrary tree having N leaves in a way that is consistent with a chromosomal description for use in a genetic algorithm. Also associated with this is the need to generate random instances for filling the initial population, and to implement crossover and mutations operators for this type of chromosome. Any suggestions will be welcome. Please minimize the amount of CS lingo in your reply, since I am not likely to be acquainted with it. Thanks in advance, Peter

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  • MVC pattern implementation. What is the n-relation between its components

    - by Srodriguez
    Dear all, I'm working in a C# project and we are , in order to get some unity across the different parts of our UI, trying to use the MVC pattern. The client is windows form based and I'm trying to create a simple MVC pattern implementation. It's been more challenging than expected, but I still have some questions regarding the MVC pattern. The problem comes mostly from the n-n relationships between its components: Here is what I've understood, but I'm not sure at all of it. Maybe someone can correct me? Model: can be shared among different Views. 1-n relationship between Model-View View: shows the state of the model. only one controller (can be shared among different views?). 1-1 relationship with the Model, 1-1 relationship with the controller Controller: handles the user actions on the view and updates the model. One controller can be shared among different views, a controller interacts only with one model? I'm not sure about the two last ones: Can a view have several controller? Or can a view share a controller with another view? Or is it only a 1:1 relationship? Can a controller handle several views? can it interact with several models? Also, I take advantage of this question to ask another MVC related question. I've suppressed all the synchronous calls between the different members of the MVC, making use of the events and delegates. One last call is still synchronous and is actually the most important one: The call between the view and the controller is still synchronous, as I need to know rather the controller has been able to handle the user's action or not. This is very bad as it means that I could block the UI thread (hence the client itself) while the controller is processing or doing some work. How can I avoid this? I can make use of the callback but then how do i know to which event the callback comes from? PS: I can't change the pattern at this stage, so please avoid answers of type "use MVP or MVVC, etc ;) Thanks!

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  • MVC pattern implementation. What is the n-relation between its components

    - by Srodriguez
    Dear all, I'm working in a C# project and we are , in order to get some unity across the different parts of our UI, trying to use the MVC pattern. The client is windows form based and I'm trying to create a simple MVC pattern implementation. It's been more challenging than expected, but I still have some questions regarding the MVC pattern. The problem comes mostly from the n-n relationships between its components: Here is what I've understood, but I'm not sure at all of it. Maybe someone can correct me? Model: can be shared among different Views. 1-n relationship between Model-View View: shows the state of the model. only one controller (can be shared among different views?). 1-1 relationship with the Model, 1-1 relationship with the controller Controller: handles the user actions on the view and updates the model. One controller can be shared among different views, a controller interacts only with one model? I'm not sure about the two last ones: Can a view have several controller? Or can a view share a controller with another view? Or is it only a 1:1 relationship? Can a controller handle several views? can it interact with several models? Also, I take advantage of this question to ask another MVC related question. I've suppressed all the synchronous calls between the different members of the MVC, making use of the events and delegates. One last call is still synchronous and is actually the most important one: The call between the view and the controller is still synchronous, as I need to know rather the controller has been able to handle the user's action or not. This is very bad as it means that I could block the UI thread (hence the client itself) while the controller is processing or doing some work. How can I avoid this? I can make use of the callback but then how do i know to which event the callback comes from? PS: I can't change the pattern at this stage, so please avoid answers of type "use MVP or MVVC, etc ;) Thanks!

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  • Idiomatic use of auto_ptr to transfer ownership to a container

    - by heycam
    I'm refreshing my C++ knowledge after not having used it in anger for a number of years. In writing some code to implement some data structure for practice, I wanted to make sure that my code was exception safe. So I've tried to use std::auto_ptrs in what I think is an appropriate way. Simplifying somewhat, this is what I have: class Tree { public: ~Tree() { /* delete all Node*s in the tree */ } void insert(const string& to_insert); ... private: struct Node { ... vector<Node*> m_children; }; Node* m_root; }; template<T> void push_back(vector<T*>& v, auto_ptr<T> x) { v.push_back(x.get()); x.release(); } void Tree::insert(const string& to_insert) { Node* n = ...; // find where to insert the new node ... push_back(n->m_children, auto_ptr<Node>(new Node(to_insert)); ... } So I'm wrapping the function that would put the pointer into the container, vector::push_back, and relying on the by-value auto_ptr argument to ensure that the Node* is deleted if the vector resize fails. Is this an idiomatic use of auto_ptr to save a bit of boilerplate in my Tree::insert? Any improvements you can suggest? Otherwise I'd have to have something like: Node* n = ...; // find where to insert the new node auto_ptr<Node> new_node(new Node(to_insert)); n->m_children.push_back(new_node.get()); new_node.release(); which kind of clutters up what would have been a single line of code if I wasn't worrying about exception safety and a memory leak. (Actually I was wondering if I could post my whole code sample (about 300 lines) and ask people to critique it for idiomatic C++ usage in general, but I'm not sure whether that kind of question is appropriate on stackoverflow.)

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  • iPhone: Can't animate contentInset while animating Nav Bar show/hide

    - by Cuzog
    In my app, I have a table view. When the user clicks a button, a UIView overlays part of that table view. It's essentially a partial modal. That table view is intentionally still scrollable while that modal is active. To allow the user to scroll to the bottom of the table view, I change the contentInset and scrollIndicatorInsets values to adjust for the smaller area above the modal. When the modal is taken away, I reset those inset values. The problem is that when the user has scrolled to the bottom of the newly adjusted inset and then dismisses the modal, the table view jumps abruptly to a new scroll position because the inset is changed instantly. I would like to animate it so there is a transition, but the beginAnimation/commitAnimations methods aren't affecting it for some reason. Edit: More info. I found the conflict. When presenting the modal, I also hide the navigation bar. The navigation bar natively animates the table view up and down as it shows and hides. When I stop animating the navigation bar, the inset animation works fine. Does anyone know what I can do to work around this conflict? Do I have to wait for the navigation bar animation to finish before adjusting the inset? If so, how to I hook onto that? Any help is greatly appreciated! The relevant code from the table view controller is here: - (void)viewDidLoad { [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(modalOpened) name:@"ModalStartedOpening" object:nil]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(modalDismissed) name:@"ModalStartedClosing" object:nil]; [super viewDidLoad]; } - (void)modalOpened { [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:0.5]; [UIView setAnimationDelegate:self]; self.tableView.contentInset = UIEdgeInsetsMake(0, 0, 201, 0); self.tableView.scrollIndicatorInsets = UIEdgeInsetsMake(0, 0, 201, 0); [UIView commitAnimations]; } - (void)modalDismissed { [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:0.5]; [UIView setAnimationDelegate:self]; self.tableView.contentInset = UIEdgeInsetsMake(0, 0, 0, 0); self.tableView.scrollIndicatorInsets = UIEdgeInsetsMake(0, 0, 0, 0); [UIView commitAnimations]; }

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  • How do I stack images to simulate depth using Core Animation?

    - by Jeffrey Berthiaume
    I have a series of UIImages with which I need to simulate depth. I can't use scaling because I need to be able to rotate the parent view, and the images should look like they're stacked visibly in front of each other, not on the same plane. I made a new ViewController-based project and put this in the viewDidLoad (as well as attached three 120x120 pixel images named 1.png, 2.png, and 3.png): - (void)viewDidLoad { // display image 3 UIImageView *three = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"3.png"]]; three.center = CGPointMake(160 + 60, 240 - 60); [self.view addSubview:three]; // rotate image 3 around the z axis // THIS IS INCORRECT CATransform3D theTransform = three.layer.transform; theTransform.m34 = 1.0 / -1000; three.layer.transform = theTransform; // display image 2 UIImageView *two = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"2.png"]]; two.center = CGPointMake(160, 240); [self.view addSubview:two]; // display image 1 UIImageView *one = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"1.png"]]; one.center = CGPointMake(160 - 60, 240 + 60); [self.view addSubview:one]; // rotate image 3 around the z axis // THIS IS INCORRECT theTransform = one.layer.transform; theTransform.m34 = 1.0 / 1000; one.layer.transform = theTransform; // release the images [one release]; [two release]; [three release]; // rotate the parent view around the y axis theTransform = self.view.layer.transform; theTransform.m14 = 1.0 / -500; self.view.layer.transform = theTransform; [super viewDidLoad]; } I have very specific reasons why I'm not using an EAGLView and why I'm not loading the images as CALayers (i.e. why I'm using UIImageViews for each one). This is just a quick demo that I can use to work out exactly what I need in my parent application. Is there some matrix way to translate these 2d images along the z-axis so they will look like what I'm trying to represent? I've gone through the other StackOverflow articles as well as the Wikipedia references, and have not found what I'm looking for -- although I might not necessarily be using the right terms for what I'm trying to do.

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  • Problem setting row backgrounds in Android Listview

    - by zchtodd
    I have an application in which I'd like one row at a time to have a certain color. This seems to work about 95% of the time, but sometimes instead of having just one row with this color, it will allow multiple rows to have the color. Specifically, a row is set to have the "special" color when it is tapped. In rare instances, the last row tapped will retain the color despite a call to setBackgroundColor attempting to make it otherwise. private OnItemClickListener mDirectoryListener = new OnItemClickListener(){ public void onItemClick(AdapterView parent, View view, int pos, long id){ if (stdir.getStationCount() == pos) { stdir.moreStations(); return; } if (playingView != null) playingView.setBackgroundColor(Color.DKGRAY); view.setBackgroundColor(Color.MAGENTA); playingView = view; playStation(pos); } }; I have confirmed with print statements that the code setting the row to gray is always called. Can anyone imagine a reason why this code might intermittently fail? If there is a pattern or condition that causes it, I can't tell. I thought it might have something to do with the activity lifecycle setting the "playingView" variable back to null, but I can't reliably reproduce the problem by switching activities or locking the phone. private class DirectoryAdapter extends ArrayAdapter { private ArrayList<Station> items; public DirectoryAdapter(Context c, int resLayoutId, ArrayList<Station> stations){ super(c, resLayoutId, stations); this.items = stations; } public int getCount(){ return items.size() + 1; } public View getView(int position, View convertView, ViewGroup parent){ View v = convertView; LayoutInflater vi = (LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); if (position == this.items.size()) { v = vi.inflate(R.layout.morerow, null); return v; } Station station = this.items.get(position); v = vi.inflate(R.layout.songrow, null); if (station.playing) v.setBackgroundColor(Color.MAGENTA); else if (station.visited) v.setBackgroundColor(Color.DKGRAY); else v.setBackgroundColor(Color.BLACK); TextView title = (TextView)v.findViewById(R.id.title); title.setText(station.name); return v; } };

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  • Spring MVC, REST, and HATEOAS

    - by SingleShot
    I'm struggling with the correct way to implement Spring MVC 3.x RESTful services with HATEOAS. Consider the following constraints: I don't want my domain entities polluted with web/rest constructs. I don't want my controllers polluted with view constructs. I want to support multiple views. Currently I have a nicely put together MVC app without HATEOAS. Domain entities are pure POJOs without any view or web/rest concepts embedded. For example: class User { public String getName() {...} public String setName(String name) {...} ... } My controllers are also simple. They provide routing and status, and delegate to Spring's view resolution framework. Note my application supports JSON, XML, and HTML, yet no domain entities or controllers have embedded view information: @Controller @RequestMapping("/users") class UserController { @RequestMapping public ModelAndView getAllUsers() { List<User> users = userRepository.findAll(); return new ModelAndView("users/index", "users", users); } @RequestMapping("/{id}") public ModelAndView getUser(@PathVariable Long id) { User user = userRepository.findById(id); return new ModelAndView("users/show", "user", user); } } So, now my issue - I'm not sure of a clean way to support HATEOAS. Here's an example. Let's say when the client asks for a User in JSON format, it comes out like this: { firstName: "John", lastName: "Smith" } Let's also say that when I support HATEOAS, I want the JSON to contain a simple "self" link that the client can then use to refresh the object, delete it, or something else. It might also have a "friends" link indicating how to get the user's list of friends: { firstName: "John", lastName: "Smith", links: [ { rel: "self", ref: "http://myserver/users/1" }, { rel: "friends", ref: "http://myserver/users/1/friends" } ] } Somehow I want to attach links to my object. I feel the right place to do this is in the controller layer as the controllers all know the correct URLs. Additionally, since I support multiple views, I feel like the right thing to do is somehow decorate my domain entities in the controller before they are converted to JSON/XML/whatever in Spring's view resolution framework. One way to do this might be to wrap the POJO in question with a generic Resource class that contains a list of links. Some view tweaking would be required to crunch it into the format I want, but its doable. Unfortunately nested resources could not be wrapped in this way. Other things that come to mind include adding links to the ModelAndView, and then customizing each of Spring's out-of-the-box view resolvers to stuff links into the generated JSON/XML/etc. What I don't want is to be constantly hand-crafting JSON/XML/etc. to accommodate various links as they come and go during the course of development. Thoughts?

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  • proper fill an image larger than screen

    - by madcat
    what I wanted to achieve here is simply fit the image width to the screen on both orientations and use UIScrollView to just allow scroll vertically to see the whole image. both viewController and view are created pragmatically. the image loaded is larger than screen on both width and height. here is the related code in my viewController: - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { return YES; } - (void)loadView { UIScreen *screen = [UIScreen mainScreen]; CGRect rect = [screen applicationFrame]; self.view = [[UIView alloc] initWithFrame:rect]; self.view.contentMode = UIViewContentModeScaleAspectFill; self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight; UIImage *img=[[UIImage alloc] initWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"image" ofType:@"png"]]; UIImageView *imgView =[[UIImageView alloc] initWithImage:img]; [img release]; imgView.contentMode = UIViewContentModeScaleAspectFill; imgView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight; [self.view addSubview:imgView]; [imgView release]; } tried all combinations for both contentMode above, did not give me correct result. the most close I am getting now: I manually resize imgView in loadView, portrait mode would display correctly since app always starts with portrait mode, but in landscape mode, the width fits correctly, but image is centered vertically rather than top aligned. if I add the imgView to a scrollView, in landscape mode it looks like contentSize is not set to full image size. but when I scroll bounce I can see the image is there in full size. question: why I need to resize it manually? in landscape mode how and where I can 'move' the imgView, so imgView.frame.origin is (0,0) and works correctly with a scroll view? Thanks! UPDATE: I added: imgView.clipsToBounds = YES; and find out in landscape mode the image bounds is smaller than screen in height. so the question becomes how to have the image view keeps original ratio (thus shows the full image always) when rotated to landscape? do I need to manually resize it after rotation again?

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  • Rendering problem with UITableview

    - by Spider-Paddy
    I have a very strange problem with a UITableview within a navigation controller on the iPhone simulator. Of the cells displayed, only some are correctly rendered. They are all supposed to look the same but the majority are missing the accessory I've set, scrolling the view changes which cell has the accessory so I suspect it's some sort of cell caching happening, although the contents are correct for each cell. I also set an image as the background and that was also only displaying sporadically but I fixed that by changing cell.backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"yellow-bar_short.png"]]; (which also only rendered a random cell with the background) to cell.backgroundColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:@"yellow-bar_short.png"]]; I now need to fix the problem with the accessory only showing on a random cell. I tried moving the code from cellForRowAtIndex to willDisplayCell but it made no difference. I put in a log command to confirm that it is running through each frame. Basically it's a table view (UITableViewCellStyleSubtitle) that gets its info from a server & is then updated by a delegate method calling reload. Code is: -(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath { NSLog(@"%@", [NSString stringWithFormat:@"Setting colours for cell %i", indexPath.row]); // Set cell background // cell.backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"yellow-bar_short.png"]]; cell.backgroundColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:@"yellow-bar_short.png"]]; cell.textLabel.backgroundColor = [UIColor clearColor]; cell.detailTextLabel.backgroundColor = [UIColor clearColor]; // detailTableViewAccessory is a view containing an imageview in this view's nib // i.e. nib <- view <- imageview <- image cell.accessoryView = detailTableViewAccessory; } // Called by data fetching object when done -(void)listDataTransferComplete:(ArticleListParser *)articleListParserObject { NSLog(@"Data parsed, reloading detail table"); self.currentTotalResultPages = (((articleListParserObject.currentArticleCount - 1) / 10) + 1); self.detailTableDataSource = [articleListParserObject.returnedArray copy]; // make a local copy of the returned array // Render table again with returned array data (neither of these 2 fixed it) [self.detailTableView performSelectorOnMainThread:@selector(reloadData) withObject:nil waitUntilDone:NO]; // [self.detailTableView reloadData]; // Re-enable necessary buttons (including table cells) letUserSelectRow = TRUE; [btnByName setEnabled:TRUE]; [btnByPrice setEnabled:TRUE]; // Remove please wait message NSLog(@"Removing please wait view"); [pleaseWaitViewControllerObject.view removeFromSuperview]; } I only included code that I thought was relevant, can supply more if needed. I can't test it on an iPhone yet so I don't know if it's maybe just a simulator anomaly or a bug in my code. I've always gotten good feedback from questions, any ideas?

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  • Zend Framework AjaxContext filters the results and Decorators not removable

    - by Janis Peisenieks
    Ok, since this problem has 2 parts, it will be easier to explain them together. So here goes: I am trying to remove the default decorators from these elements, since I am using a little different way of styling them. But no matter what i do, the DtDDWrapper still shows up. If I try to remove all of the decorators, all of the fields below disappear. public function newfieldAction() { $ajaxContext = $this->_helper->getHelper('AjaxContext'); $ajaxContext->addActionContext('newfield', 'html')->initContext(); $id = $this->_getParam('id', null); $id1=$id+1; $id2=$id+2; $element = new Zend_Form_Element_Text("newTitle$id1"); $element->setOptions(array('escape'=>false)); $element->setRequired(true)->setLabel('Vertiba')->removeDecorator('label'); $tinyelement=new Zend_Form_Element_Text("newName$id"); $tinyelement->setRequired(true)->setOptions(array('escape'=>false))->setLabel('Vertiba')->removeDecorator('label'); $textarea_element = new Zend_Form_Element_Textarea("newText$id2"); $textarea_element->setRequired(true)->setOptions(array('escape'=>false))->setLabel('Vertiba')->removeDecorator('label'); $this->view->descriptionField = "<td>".$textarea_element->__toString()."</td>"; $this->view->titleField = $element->__toString(); $this->view->field = $tinyelement->__toString(); $this->view->id=$id; } The context view script seams to trim my code in one way or another. When I try to put a <td> or a <table> tag in the view script, it just skips the tags. Is there a way to stop this escaping from happening? My view script: id; ?" asdfasdfasdfasd field ? titleField ? descriptionField ? id ?"remove P.S. the code formatting system is barfing at me, could someone please help me with the formatting of the code?

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  • RequestFactoryEditorDriver getting edited data after flush

    - by Deanna
    Let me start with I have a solution, but I don't really think it is elegant. So, I am looking for a cleaner way to do this. I have an EntityProxy displayed in a view panel. The view panel is a RequestFactoryEditorDriver only using display mode. The user clicks on a data element and opens a popup editor to edit a data element of the EntityProxy with a few more bits of data than is displayed in the view panel. When the user saves the element I need the view panel to update the display. I ran into a problem because the RequestFactoryEditorDriver of the popup editor flow doesn't let you get to the edited data. The driver uses the passed in context and sends it to the server. The context returned out of flush only allows a Receiver even if you cast it to the type of context you stored in the editor driver in the edit() call. It doesn't appear to send and EntityProxyChanged event either, so I couldn't listen for that and update the display view. The solution I found was to change my domain object persist to return the newly saved entity. Then create the popup editor like this editor.getSaveButtonClickHandler().addClickHandler(createSaveHandler(driver, editor)); // initialize the Driver and edit the given text. driver.initialize(rf, editor); PlayerProfileCtx ctx = rf.playerProfile(); ctx.persist().using(playerProfile).with(driver.getPaths()) .to(new Receiver<PlayerProfileProxy>(){ @Override public void onSuccess(PlayerProfileProxy profile) { editor.hide(); playerProfile = profile; viewDriver.display(playerProfile); } }); driver.edit(playerProfile, ctx); editor.centerAndShow(); Then in the save handler I just fire the context I get from the flush. While this approach works, it doesn't seem right. It would seem I should subscribe to the entitychanged event in the display view and update the entity and the view from there. Also this approach saves the complete entity, not just the changed bits, which will increase bandwidth usage. What I would think should happen, is when you flush the entity it should 'optimistically' update the rf managed version of the entity and fire the entity proxy changed event. Only reverting the entity if something went wrong in the save. The actual save should only send the changed bits. In this way there isn't a need to refetch the whole entity and send that complete data over the wire twice. Is there a better solution?

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  • IPhone iOs 5, need help getting my tab bar at the top to work

    - by Patrick
    I wanted to have the tab bar at the top. So i created a new project in XCode. Added a view and then inside that view i added (scrollbar, text and another view). See picture. What i wanted was to have my tab bar at the top. Then in the middle would be the contents from the tab bar and below it a small copyright text. See picture. No idea how to make this correctly. I have tried to create the UITabBarController on the fly and then assign it into the view at the top. (Top white space on the picture dedicated for the tab bar). Here is my code to init the MainWindow. MainWindow.h #import <UIKit/UIKit.h> @class Intro; @interface MainWindow : UIViewController @property (strong, nonatomic) IBOutlet UIScrollView *mainContentFrame; @property (strong, nonatomic) IBOutlet UIView *mainTabBarView; @property (strong, nonatomic) UITabBarController *mainTabBar; @property (nonatomic, strong) Intro *intro; // Trying to get this tab to show in the tab bar @end MainWindow.m #import "MainWindow.h" #import "Intro.h" @interface MainWindow () @end @implementation MainWindow @synthesize mainContentFrame = _mainContentFrame; @synthesize mainTabBarView = _mainTabBarView; @synthesize mainTabBar = _mainTabBar; @synthesize intro = _intro; - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil { self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; if (self) { // Custom initialization } return self; } - (void)viewDidLoad { _intro = [[Intro alloc] init]; NSArray *allViews = [[NSArray alloc] initWithObjects:_intro, nil]; [super viewDidLoad]; // Do any additional setup after loading the view. _mainTabBar = [[UITabBarController alloc] init]; [_mainTabBar setViewControllers:allViews]; [_mainTabBarView.window addSubview:_mainTabBar.tabBarController.view]; } - (void)viewDidUnload { [self setMainTabBar:nil]; [self setMainContentFrame:nil]; [self setMainContentFrame:nil]; [super viewDidUnload]; // Release any retained subviews of the main view. } - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation { return (interfaceOrientation == UIInterfaceOrientationPortrait); } @end What am i missing to get this to work? Wanted the content to end up in the scrollview so that all tabs are scrollable.

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  • UIButton does not respond to touch events after changing its position using setFrame

    - by Pranathi
    I have a view controller class (child) which extends from view controller class (parent). In the parent class's loadView() method I create a sub-view (named myButtonView) with two buttons (buttons are horizontally laid out in the subview) and add it to the main view. In the subclass I need to shift these two buttons up by 50pixels. So, I am shifting the buttonView by calling the setFrame method. This makes the buttons shift and render properly but they do not respond to touch events after this. Buttons work properly in the views of Parent class type. In the child class type view also, if I comment out the setFrame() call the buttons work properly. How can I shift the buttons and still make them respond to touch events? Any help is appreciated. Following is snippets of the code. In the parent class: - (void)loadView { // Some code... CGRect buttonFrameRect = CGRectMake(0,yOffset+1,screenRect.size.width,KButtonViewHeight); myButtonView = [[UIView alloc]initWithFrame:buttonFrameRect]; myButtonView.backgroundColor = [UIColor clearColor]; [self.view addSubview:myButtonView]; // some code... CGRect nxtButtonRect = CGRectMake(screenRect.size.width - 110, 5, 100, 40); myNxtButton = [UIButton buttonWithType:UIButtonTypeCustom]; [myNxtButton setTitle:@"Submit" forState:UIControlStateNormal]; myNxtButton.frame = nxtButtonRect; myNxtButton.backgroundColor = [UIColor clearColor]; [myNxtButton addTarget:self action:@selector(nextButtonPressed:) forControlEvents:UIControlEventTouchUpInside]; [myButtonView addSubview:myNxtButton]; CGRect backButtonRect = CGRectMake(10, 5, 100, 40); myBackButton = [UIButton buttonWithType:UIButtonTypeCustom]; [myBackButton setTitle:@"Back" forState:UIControlStateNormal]; myBackButton.frame = backButtonRect; myBackButton.backgroundColor = [UIColor clearColor]; [myBackButton addTarget:self action:@selector(backButtonPressed:) forControlEvents:UIControlEventTouchUpInside]; [myButtonView addSubview:myBackButton]; // Some code... } In the child class: - (void)loadView { [super loadView]; //Some code .. CGRect buttonViewRect = myButtonView.frame; buttonViewRect.origin.y = yOffset; // This is basically original yOffset + 50 [myButtonView setFrame:buttonViewRect]; yOffset += KButtonViewHeight; // Add some other view below myButtonView .. }

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  • ANTS CLR and Memory Profiler In Depth Review (Part 1 of 2 &ndash; CLR Profiler)

    - by ToStringTheory
    One of the things that people might not know about me, is my obsession to make my code as efficient as possible.  Many people might not realize how much of a task or undertaking that this might be, but it is surely a task as monumental as climbing Mount Everest, except this time it is a challenge for the mind…  In trying to make code efficient, there are many different factors that play a part – size of project or solution, tiers, language used, experience and training of the programmer, technologies used, maintainability of the code – the list can go on for quite some time. I spend quite a bit of time when developing trying to determine what is the best way to implement a feature to accomplish the efficiency that I look to achieve.  One program that I have recently come to learn about – Red Gate ANTS Performance (CLR) and Memory profiler gives me tools to accomplish that job more efficiently as well.  In this review, I am going to cover some of the features of the ANTS profiler set by compiling some hideous example code to test against. Notice As a member of the Geeks With Blogs Influencers program, one of the perks is the ability to review products, in exchange for a free license to the program.  I have not let this affect my opinions of the product in any way, and Red Gate nor Geeks With Blogs has tried to influence my opinion regarding this product in any way. Introduction The ANTS Profiler pack provided by Red Gate was something that I had not heard of before receiving an email regarding an offer to review it for a license.  Since I look to make my code efficient, it was a no brainer for me to try it out!  One thing that I have to say took me by surprise is that upon downloading the program and installing it you fill out a form for your usual contact information.  Sure enough within 2 hours, I received an email from a sales representative at Red Gate asking if she could help me to achieve the most out of my trial time so it wouldn’t go to waste.  After replying to her and explaining that I was looking to review its feature set, she put me in contact with someone that setup a demo session to give me a quick rundown of its features via an online meeting.  After having dealt with a massive ordeal with one of my utility companies and their complete lack of customer service, Red Gates friendly and helpful representatives were a breath of fresh air, and something I was thankful for. ANTS CLR Profiler The ANTS CLR profiler is the thing I want to focus on the most in this post, so I am going to dive right in now. Install was simple and took no time at all.  It installed both the profiler for the CLR and Memory, but also visual studio extensions to facilitate the usage of the profilers (click any images for full size images): The Visual Studio menu options (under ANTS menu) Starting the CLR Performance Profiler from the start menu yields this window If you follow the instructions after launching the program from the start menu (Click File > New Profiling Session to start a new project), you are given a dialog with plenty of options for profiling: The New Session dialog.  Lots of options.  One thing I noticed is that the buttons in the lower right were half-covered by the panel of the application.  If I had to guess, I would imagine that this is caused by my DPI settings being set to 125%.  This is a problem I have seen in other applications as well that don’t scale well to different dpi scales. The profiler options give you the ability to profile: .NET Executable ASP.NET web application (hosted in IIS) ASP.NET web application (hosted in IIS express) ASP.NET web application (hosted in Cassini Web Development Server) SharePoint web application (hosted in IIS) Silverlight 4+ application Windows Service COM+ server XBAP (local XAML browser application) Attach to an already running .NET 4 process Choosing each option provides a varying set of other variables/options that one can set including options such as application arguments, operating path, record I/O performance performance counters to record (43 counters in all!), etc…  All in all, they give you the ability to profile many different .Net project types, and make it simple to do so.  In most cases of my using this application, I would be using the built in Visual Studio extensions, as they automatically start a new profiling project in ANTS with the options setup, and start your program, however RedGate has made it easy enough to profile outside of Visual Studio as well. On the flip side of this, as someone who lives most of their work life in Visual Studio, one thing I do wish is that instead of opening an entirely separate application/gui to perform profiling after launching, that instead they would provide a Visual Studio panel with the information, and integrate more of the profiling project information into Visual Studio.  So, now that we have an idea of what options that the profiler gives us, its time to test its abilities and features. Horrendous Example Code – Prime Number Generator One of my interests besides development, is Physics and Math – what I went to college for.  I have especially always been interested in prime numbers, as they are something of a mystery…  So, I decided that I would go ahead and to test the abilities of the profiler, I would write a small program, website, and library to generate prime numbers in the quantity that you ask for.  I am going to start off with some terrible code, and show how I would see the profiler being used as a development tool. First off, the IPrimes interface (all code is downloadable at the end of the post): interface IPrimes { IEnumerable<int> GetPrimes(int retrieve); } Simple enough, right?  Anything that implements the interface will (hopefully) provide an IEnumerable of int, with the quantity specified in the parameter argument.  Next, I am going to implement this interface in the most basic way: public class DumbPrimes : IPrimes { public IEnumerable<int> GetPrimes(int retrieve) { //store a list of primes already found var _foundPrimes = new List<int>() { 2, 3 }; //if i ask for 1 or two primes, return what asked for if (retrieve <= _foundPrimes.Count()) return _foundPrimes.Take(retrieve); //the next number to look at int _analyzing = 4; //since I already determined I don't have enough //execute at least once, and until quantity is sufficed do { //assume prime until otherwise determined bool isPrime = true; //start dividing at 2 //divide until number is reached, or determined not prime for (int i = 2; i < _analyzing && isPrime; i++) { //if (i) goes into _analyzing without a remainder, //_analyzing is NOT prime if (_analyzing % i == 0) isPrime = false; } //if it is prime, add to found list if (isPrime) _foundPrimes.Add(_analyzing); //increment number to analyze next _analyzing++; } while (_foundPrimes.Count() < retrieve); return _foundPrimes; } } This is the simplest way to get primes in my opinion.  Checking each number by the straight definition of a prime – is it divisible by anything besides 1 and itself. I have included this code in a base class library for my solution, as I am going to use it to demonstrate a couple of features of ANTS.  This class library is consumed by a simple non-MVVM WPF application, and a simple MVC4 website.  I will not post the WPF code here inline, as it is simply an ObservableCollection<int>, a label, two textbox’s, and a button. Starting a new Profiling Session So, in Visual Studio, I have just completed my first stint developing the GUI and DumbPrimes IPrimes class, so now I want to check my codes efficiency by profiling it.  All I have to do is build the solution (surprised initiating a profiling session doesn’t do this, but I suppose I can understand it), and then click the ANTS menu, followed by Profile Performance.  I am then greeted by the profiler starting up and already monitoring my program live: You are provided with a realtime graph at the top, and a pane at the bottom giving you information on how to proceed.  I am going to start by asking my program to show me the first 15000 primes: After the program finally began responding again (I did all the work on the main UI thread – how bad!), I stopped the profiler, which did kill the process of my program too.  One important thing to note, is that the profiler by default wants to give you a lot of detail about the operation – line hit counts, time per line, percent time per line, etc…  The important thing to remember is that this itself takes a lot of time.  When running my program without the profiler attached, it can generate the 15000 primes in 5.18 seconds, compared to 74.5 seconds – almost a 1500 percent increase.  While this may seem like a lot, remember that there is a trade off.  It may be WAY more inefficient, however, I am able to drill down and make improvements to specific problem areas, and then decrease execution time all around. Analyzing the Profiling Session After clicking ‘Stop Profiling’, the process running my application stopped, and the entire execution time was automatically selected by ANTS, and the results shown below: Now there are a number of interesting things going on here, I am going to cover each in a section of its own: Real Time Performance Counter Bar (top of screen) At the top of the screen, is the real time performance bar.  As your application is running, this will constantly update with the currently selected performance counters status.  A couple of cool things to note are the fact that you can drag a selection around specific time periods to drill down the detail views in the lower 2 panels to information pertaining to only that period. After selecting a time period, you can bookmark a section and name it, so that it is easy to find later, or after reloaded at a later time.  You can also zoom in, out, or fit the graph to the space provided – useful for drilling down. It may be hard to see, but at the top of the processor time graph below the time ticks, but above the red usage graph, there is a green bar. This bar shows at what times a method that is selected in the ‘Call tree’ panel is called. Very cool to be able to click on a method and see at what times it made an impact. As I said before, ANTS provides 43 different performance counters you can hook into.  Click the arrow next to the Performance tab at the top will allow you to change between different counters if you have them selected: Method Call Tree, ADO.Net Database Calls, File IO – Detail Panel Red Gate really hit the mark here I think. When you select a section of the run with the graph, the call tree populates to fill a hierarchical tree of method calls, with information regarding each of the methods.   By default, methods are hidden where the source is not provided (framework type code), however, Red Gate has integrated Reflector into ANTS, so even if you don’t have source for something, you can select a method and get the source if you want.  Methods are also hidden where the impact is seen as insignificant – methods that are only executed for 1% of the time of the overall calling methods time; in other words, working on making them better is not where your efforts should be focused. – Smart! Source Panel – Detail Panel The source panel is where you can see line level information on your code, showing the code for the currently selected method from the Method Call Tree.  If the code is not available, Reflector takes care of it and shows the code anyways! As you can notice, there does seem to be a problem with how ANTS determines what line is the actual line that a call is completed on.  I have suspicions that this may be due to some of the inline code optimizations that the CLR applies upon compilation of the assembly.  In a method with comments, the problem is much more severe: As you can see here, apparently the most offending code in my base library was a comment – *gasp*!  Removing the comments does help quite a bit, however I hope that Red Gate works on their counter algorithm soon to improve the logic on positioning for statistics: I did a small test just to demonstrate the lines are correct without comments. For me, it isn’t a deal breaker, as I can usually determine the correct placements by looking at the application code in the region and determining what makes sense, but it is something that would probably build up some irritation with time. Feature – Suggest Method for Optimization A neat feature to really help those in need of a pointer, is the menu option under tools to automatically suggest methods to optimize/improve: Nice feature – clicking it filters the call tree and stars methods that it thinks are good candidates for optimization.  I do wish that they would have made it more visible for those of use who aren’t great on sight: Process Integration I do think that this could have a place in my process.  After experimenting with the profiler, I do think it would be a great benefit to do some development, testing, and then after all the bugs are worked out, use the profiler to check on things to make sure nothing seems like it is hogging more than its fair share.  For example, with this program, I would have developed it, ran it, tested it – it works, but slowly. After looking at the profiler, and seeing the massive amount of time spent in 1 method, I might go ahead and try to re-implement IPrimes (I actually would probably rewrite the offending code, but so that I can distribute both sets of code easily, I’m just going to make another implementation of IPrimes).  Using two pieces of knowledge about prime numbers can make this method MUCH more efficient – prime numbers fall into two buckets 6k+/-1 , and a number is prime if it is not divisible by any other primes before it: public class SmartPrimes : IPrimes { public IEnumerable<int> GetPrimes(int retrieve) { //store a list of primes already found var _foundPrimes = new List<int>() { 2, 3 }; //if i ask for 1 or two primes, return what asked for if (retrieve <= _foundPrimes.Count()) return _foundPrimes.Take(retrieve); //the next number to look at int _k = 1; //since I already determined I don't have enough //execute at least once, and until quantity is sufficed do { //assume prime until otherwise determined bool isPrime = true; int potentialPrime; //analyze 6k-1 //assign the value to potential potentialPrime = 6 * _k - 1; //if there are any primes that divise this, it is NOT a prime number //using PLINQ for quick boost isPrime = !_foundPrimes.AsParallel() .Any(prime => potentialPrime % prime == 0); //if it is prime, add to found list if (isPrime) _foundPrimes.Add(potentialPrime); if (_foundPrimes.Count() == retrieve) break; //analyze 6k+1 //assign the value to potential potentialPrime = 6 * _k + 1; //if there are any primes that divise this, it is NOT a prime number //using PLINQ for quick boost isPrime = !_foundPrimes.AsParallel() .Any(prime => potentialPrime % prime == 0); //if it is prime, add to found list if (isPrime) _foundPrimes.Add(potentialPrime); //increment k to analyze next _k++; } while (_foundPrimes.Count() < retrieve); return _foundPrimes; } } Now there are definitely more things I can do to help make this more efficient, but for the scope of this example, I think this is fine (but still hideous)! Profiling this now yields a happy surprise 27 seconds to generate the 15000 primes with the profiler attached, and only 1.43 seconds without.  One important thing I wanted to call out though was the performance graph now: Notice anything odd?  The %Processor time is above 100%.  This is because there is now more than 1 core in the operation.  A better label for the chart in my mind would have been %Core time, but to each their own. Another odd thing I noticed was that the profiler seemed to be spot on this time in my DumbPrimes class with line details in source, even with comments..  Odd. Profiling Web Applications The last thing that I wanted to cover, that means a lot to me as a web developer, is the great amount of work that Red Gate put into the profiler when profiling web applications.  In my solution, I have a simple MVC4 application setup with 1 page, a single input form, that will output prime values as my WPF app did.  Launching the profiler from Visual Studio as before, nothing is really different in the profiler window, however I did receive a UAC prompt for a Red Gate helper app to integrate with the web server without notification. After requesting 500, 1000, 2000, and 5000 primes, and looking at the profiler session, things are slightly different from before: As you can see, there are 4 spikes of activity in the processor time graph, but there is also something new in the call tree: That’s right – ANTS will actually group method calls by get/post operations, so it is easier to find out what action/page is giving the largest problems…  Pretty cool in my mind! Overview Overall, I think that Red Gate ANTS CLR Profiler has a lot to offer, however I think it also has a long ways to go.  3 Biggest Pros: Ability to easily drill down from time graph, to method calls, to source code Wide variety of counters to choose from when profiling your application Excellent integration/grouping of methods being called from web applications by request – BRILLIANT! 3 Biggest Cons: Issue regarding line details in source view Nit pick – Processor time vs. Core time Nit pick – Lack of full integration with Visual Studio Ratings Ease of Use (7/10) – I marked down here because of the problems with the line level details and the extra work that that entails, and the lack of better integration with Visual Studio. Effectiveness (10/10) – I believe that the profiler does EXACTLY what it purports to do.  Especially with its large variety of performance counters, a definite plus! Features (9/10) – Besides the real time performance monitoring, and the drill downs that I’ve shown here, ANTS also has great integration with ADO.Net, with the ability to show database queries run by your application in the profiler.  This, with the line level details, the web request grouping, reflector integration, and various options to customize your profiling session I think create a great set of features! Customer Service (10/10) – My entire experience with Red Gate personnel has been nothing but good.  their people are friendly, helpful, and happy! UI / UX (8/10) – The interface is very easy to get around, and all of the options are easy to find.  With a little bit of poking around, you’ll be optimizing Hello World in no time flat! Overall (8/10) – Overall, I am happy with the Performance Profiler and its features, as well as with the service I received when working with the Red Gate personnel.  I WOULD recommend you trying the application and seeing if it would fit into your process, BUT, remember there are still some kinks in it to hopefully be worked out. My next post will definitely be shorter (hopefully), but thank you for reading up to here, or skipping ahead!  Please, if you do try the product, drop me a message and let me know what you think!  I would love to hear any opinions you may have on the product. Code Feel free to download the code I used above – download via DropBox

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  • The case of the phantom ADF developer (and other yarns)

    - by Chris Muir
    A few years of ADF experience means I see common mistakes made by different developers, some I regularly make myself.  This post is designed to assist beginners to Oracle JDeveloper Application Development Framework (ADF) avoid a common ADF pitfall, the case of the phantom ADF developer [add Scooby-Doo music here]. ADF Business Components - triggers, default table values and instead of views. Oracle's JDeveloper tutorials help with the A-B-Cs of ADF development, typically built on the nice 'n safe demo schema provided by with the Oracle database such as the HR demo schema. However it's not too long until ADF beginners, having built up some confidence from learning with the tutorials and vanilla demo schemas, start building ADF Business Components based upon their own existing database schema objects.  This is where unexpected problems can sneak in. The crime Developers may encounter a surprising error at runtime when editing a record they just created or updated and committed to the database, based on their own existing tables, namely the error: JBO-25014: Another user has changed the row with primary key oracle.jbo.Key[x] ...where X is the primary key value of the row at hand.  In a production environment with multiple users this error may be legit, one of the other users has updated the row since you queried it.  Yet in a development environment this error is just plain confusing.  If developers are isolated in their own database, creating and editing records they know other users can't possibly be working with, or all the other developers have gone home for the day, how is this error possible? There are no other users?  It must be the phantom ADF developer! [insert dramatic music here] The following picture is what you'll see in the Business Component Browser, and you'll receive a similar error message via an ADF Faces page: A false conclusion What can possibly cause this issue if it isn't our phantom ADF developer?  Doesn't ADF BC implement record locking, locking database records when the row is modified in the ADF middle-tier by a user?  How can our phantom ADF developer even take out a lock if this is the case?  Maybe ADF has a bug, maybe ADF isn't implementing record locking at all?  Shouldn't we see the error "JBO-26030: Failed to lock the record, another user holds the lock" as we attempt to modify the record, why do we see JBO-25014? : Let's verify that ADF is in fact issuing the correct SQL LOCK-FOR-UPDATE statement to the database. First we need to verify ADF's locking strategy.  It is determined by the Application Module's jbo.locking.mode property.  The default (as of JDev 11.1.1.4.0 if memory serves me correct) and recommended value is optimistic, and the other valid value is pessimistic. Next we need a mechanism to check that ADF is issuing the LOCK statements to the database.  We could ask DBAs to monitor locks with OEM, but optimally we'd rather not involve overworked DBAs in this process, so instead we can use the ADF runtime setting –Djbo.debugoutput=console.  At runtime this options turns on instrumentation within the ADF BC layer, which among a lot of extra detail displayed in the log window, will show the actual SQL statement issued to the database, including the LOCK statement we're looking to confirm. Setting our locking mode to pessimistic, opening the Business Components Browser of a JSF page allowing us to edit a record, say the CHARGEABLE field within a BOOKINGS record where BOOKING_NO = 1206, upon editing the record see among others the following log entries: [421] Built select: 'SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings'[422] Executing LOCK...SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings WHERE BOOKING_NO=:1 FOR UPDATE NOWAIT[423] Where binding param 1: 1206  As can be seen on line 422, in fact a LOCK-FOR-UPDATE is indeed issued to the database.  Later when we commit the record we see: [441] OracleSQLBuilder: SAVEPOINT 'BO_SP'[442] OracleSQLBuilder Executing, Lock 1 DML on: BOOKINGS (Update)[443] UPDATE buf Bookings>#u SQLStmtBufLen: 210, actual=62[444] UPDATE BOOKINGS Bookings SET CHARGEABLE=:1 WHERE BOOKING_NO=:2[445] Update binding param 1: N[446] Where binding param 2: 1206[447] BookingsView1 notify COMMIT ... [448] _LOCAL_VIEW_USAGE_model_Bookings_ResourceTypesView1 notify COMMIT ... [449] EntityCache close prepared statement ....and as a result the changes are saved to the database, and the lock is released. Let's see what happens when we use the optimistic locking mode, this time to change the same BOOKINGS record CHARGEABLE column again.  As soon as we edit the record we see little activity in the logs, nothing to indicate any SQL statement, let alone a LOCK has been taken out on the row. However when we save our records by issuing a commit, the following is recorded in the logs: [509] OracleSQLBuilder: SAVEPOINT 'BO_SP'[510] OracleSQLBuilder Executing doEntitySelect on: BOOKINGS (true)[511] Built select: 'SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings'[512] Executing LOCK...SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings WHERE BOOKING_NO=:1 FOR UPDATE NOWAIT[513] Where binding param 1: 1205[514] OracleSQLBuilder Executing, Lock 2 DML on: BOOKINGS (Update)[515] UPDATE buf Bookings>#u SQLStmtBufLen: 210, actual=62[516] UPDATE BOOKINGS Bookings SET CHARGEABLE=:1 WHERE BOOKING_NO=:2[517] Update binding param 1: Y[518] Where binding param 2: 1205[519] BookingsView1 notify COMMIT ... [520] _LOCAL_VIEW_USAGE_model_Bookings_ResourceTypesView1 notify COMMIT ... [521] EntityCache close prepared statement Again even though we're seeing the midtier delay the LOCK statement until commit time, it is in fact occurring on line 412, and released as part of the commit issued on line 419.  Therefore with either optimistic or pessimistic locking a lock is indeed issued. Our conclusion at this point must be, unless there's the unlikely cause the LOCK statement is never really hitting the database, or the even less likely cause the database has a bug, then ADF does in fact take out a lock on the record before allowing the current user to update it.  So there's no way our phantom ADF developer could even modify the record if he tried without at least someone receiving a lock error. Hmm, we can only conclude the locking mode is a red herring and not the true cause of our problem.  Who is the phantom? At this point we'll need to conclude that the error message "JBO-25014: Another user has changed" is somehow legit, even though we don't understand yet what's causing it. This leads onto two further questions, how does ADF know another user has changed the row, and what's been changed anyway? To answer the first question, how does ADF know another user has changed the row, the Fusion Guide's section 4.10.11 How to Protect Against Losing Simultaneous Updated Data , that details the Entity Object Change-Indicator property, gives us the answer: At runtime the framework provides automatic "lost update" detection for entity objects to ensure that a user cannot unknowingly modify data that another user has updated and committed in the meantime. Typically, this check is performed by comparing the original values of each persistent entity attribute against the corresponding current column values in the database at the time the underlying row is locked. Before updating a row, the entity object verifies that the row to be updated is still consistent with the current state of the database.  The guide further suggests to make this solution more efficient: You can make the lost update detection more efficient by identifying any attributes of your entity whose values you know will be updated whenever the entity is modified. Typical candidates include a version number column or an updated date column in the row.....To detect whether the row has been modified since the user queried it in the most efficient way, select the Change Indicator option to compare only the change-indicator attribute values. We now know that ADF BC doesn't use the locking mechanism at all to protect the current user against updates, but rather it keeps a copy of the original record fetched, separate to the user changed version of the record, and it compares the original record against the one in the database when the lock is taken out.  If values don't match, be it the default compare-all-columns behaviour, or the more efficient Change Indicator mechanism, ADF BC will throw the JBO-25014 error. This leaves one last question.  Now we know the mechanism under which ADF identifies a changed row, what we don't know is what's changed and who changed it? The real culprit What's changed?  We know the record in the mid-tier has been changed by the user, however ADF doesn't use the changed record in the mid-tier to compare to the database record, but rather a copy of the original record before it was changed.  This leaves us to conclude the database record has changed, but how and by who? There are three potential causes: Database triggers The database trigger among other uses, can be configured to fire PLSQL code on a database table insert, update or delete.  In particular in an insert or update the trigger can override the value assigned to a particular column.  The trigger execution is actioned by the database on behalf of the user initiating the insert or update action. Why this causes the issue specific to our ADF use, is when we insert or update a record in the database via ADF, ADF keeps a copy of the record written to the database.  However the cached record is instantly out of date as the database triggers have modified the record that was actually written to the database.  Thus when we update the record we just inserted or updated for a second time to the database, ADF compares its original copy of the record to that in the database, and it detects the record has been changed – giving us JBO-25014. This is probably the most common cause of this problem. Default values A second reason this issue can occur is another database feature, default column values.  When creating a database table the schema designer can define default values for specific columns.  For example a CREATED_BY column could be set to SYSDATE, or a flag column to Y or N.  Default values are only used by the database when a user inserts a new record and the specific column is assigned NULL.  The database in this case will overwrite the column with the default value. As per the database trigger section, it then becomes apparent why ADF chokes on this feature, though it can only specifically occur in an insert-commit-update-commit scenario, not the update-commit-update-commit scenario. Instead of trigger views I must admit I haven't double checked this scenario but it seems plausible, that of the Oracle database's instead of trigger view (sometimes referred to as instead of views).  A view in the database is based on a query, and dependent on the queries complexity, may support insert, update and delete functionality to a limited degree.  In order to support fully insertable, updateable and deletable views, Oracle introduced the instead of view, that gives the view designer the ability to not only define the view query, but a set of programmatic PLSQL triggers where the developer can define their own logic for inserts, updates and deletes. While this provides the database programmer a very powerful feature, it can cause issues for our ADF application.  On inserting or updating a record in the instead of view, the record and it's data that goes in is not necessarily the data that comes out when ADF compares the records, as the view developer has the option to practically do anything with the incoming data, including throwing it away or pushing it to tables which aren't used by the view underlying query for fetching the data. Readers are at this point reminded that this article is specifically about how the JBO-25014 error occurs in the context of 1 developer on an isolated database.  The article is not considering how the error occurs in a production environment where there are multiple users who can cause this error in a legitimate fashion.  Assuming none of the above features are the cause of the problem, and optimistic locking is turned on (this error is not possible if pessimistic locking is the default mode *and* none of the previous causes are possible), JBO-25014 is quite feasible in a production ADF application if 2 users modify the same record. At this point under project timelines pressure, the obvious fix for developers is to drop both database triggers and default values from the underlying tables.  However we must be careful that these legacy constructs aren't used and assumed to be in place by other legacy systems.  Dropping the database triggers or default value that the existing Oracle Forms  applications assumes and requires to be in place could cause unexpected behaviour and bugs in the Forms application.  Proficient software engineers would recognize such a change may require a partial or full regression test of the existing legacy system, a potentially costly and timely exercise, not ideal. Solving the mystery once and for all Luckily ADF has built in functionality to deal with this issue, though it's not a surprise, as Oracle as the author of ADF also built the database, and are fully aware of the Oracle database's feature set.  At the Entity Object attribute level, the Refresh After Insert and Refresh After Update properties.  Simply selecting these instructs ADF BC after inserting or updating a record to the database, to expect the database to modify the said attributes, and read a copy of the changed attributes back into its cached mid-tier record.  Thus next time the developer modifies the current record, the comparison between the mid-tier record and the database record match, and JBO-25014: Another user has changed" is no longer an issue. [Post edit - as per the comment from Oracle's Steven Davelaar below, as he correctly points out the above solution will not work for instead-of-triggers views as it relies on SQL RETURNING clause which is incompatible with this type of view] Alternatively you can set the Change Indicator on one of the attributes.  This will work as long as the relating column for the attribute in the database itself isn't inadvertently updated.  In turn you're possibly just masking the issue rather than solving it, because if another developer turns the Change Indicator back on the original issue will return.

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