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  • Whether to put method code in a VB.Net data storage class, or put it in a separate class?

    - by Alan K
    TLDR summary: (a) Should I include (lengthy) method code in classes which may spawn multiple objects at runtime, (b) does doing so cause memory usage bloat, (c) if so should I "outsource" the code to a class that is loaded only once and have the class methods call that, or alternatively (d) does the code get loaded only once with the object definition anyway and I'm worrying about nothing? ........ I don't know whether there's a good answer to this but if there is I haven't found it yet by searching in the usual places. In my VB.Net (2010 if it matters) WinForms project I have about a dozen or so class objects in an object model. Some of these are pretty simple and do little more than act as data storage repositories. The ones further up the object model, however, have an increasing number of methods. There can be a significant number of higher level objects in use though the exact number will be runtime dependent so I can't be more precise than that. As I was writing the method code for one of the top level ones I noticed that it was starting to get quite lengthy. Memory optimisation is something of a lost art given how much memory the average PC has these days but I don't want to make my application a resource hog. So my questions for anyone who knows .Net way better than I do (of which there will be many) are: Is the code loaded into memory with each instance of the class that's created? Alternatively is it loaded only once with the definition of the class, and all derived objects just refer to that definition? (I'm not really sure how that could be possible given that, for example, event handlers can be assigned dynamically, but no harm asking.) If the answer to the first one is yes, would it be more efficient to write the code in a "utility" object which is loaded only once and called from the real class' methods? Any thoughts appreciated.

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  • Using sortable_element in Rails on a list generated by a find()

    - by Eli B.
    Hey all, I'm trying to use the scriptaculous helper method sortable_element to implement a drag-and-drop sortable list in my Rails application. While the code for the view looks pretty simple, I'm really not quite sure what to write in the controller to update the "position" column. Here's what I've got in my view, "_show_related_pgs.erb": <ul id = "interest_<%=@related_interest.id.to_s%>_siblings_list"> <%= render :partial => "/interests/peer_group_map", :collection => @maps, :as => :related_pg %> </ul> <%= sortable_element("interest_"+@related_interest.id.to_s+"_siblings_list", :url => {:action => :resort_related_pgs}, :handle => "drag" ) %> <br/> And here's the relevant line from the partial, "interests/peer_group_map.erb" <li class = "interest_<%=@related_interest.id.to_s%>_siblings_list" id = "interest_<%=related_pg.interest_id.to_s%>_siblings_list_<%=related_pg.id.to_s%>"> The Scriptaculous UI magic works fine with these, but I am unsure as to how to change the "position" column in the db to reflect this. Should I be passing the collection @maps back to the controller and tell it to iterate through that and increment/decrement the attribute "position" in each? If so, how can I tell which item was moved up, and which down? I couldn't find anything specific using Chrome dev-tools in the generated html. After each reordering, I also need to re-render the collection @maps since the position is being printed out next to the name of each interest (I'm using it as the "handle" specified in my call to sortable_element() above) - though this should be trivial. Any thoughts? Thanks, -e

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  • Passing.getText() String to another class

    - by DanMc
    I'm currently working on a first year university project and I have a problem, although I doubt it's a very complicated one, but I've been searching and I just can't find a suitable answer to it. The problem concerns two classes. A gui class (class1) and another class (class2). I have a JTextField in class1 and am trying to pass through the .getText() value to class2 and store it in a String type variable. The current code I'm trying to achieve this with is the following: (Class1) private JTextField textField = new JTextField("Something"); ... public String getTextFieldString() { return textField.getText(); } (Class2) private c1 Class1 = new Class1(); private String s = new String(); ... s = c1.getTextFieldString(); I'm pretty new to coding, I've read that maybe I need to pass through an argument somewhere and I assume that's because textField is not static in itself, it changes when somebody enters a new value. (sorry for stating the obvious there.) Anyway, help is appreciated. Thanks a lot!

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  • .NET 4 ... Parallel.ForEach() question

    - by CirrusFlyer
    I understand that the new TPL (Task Parallel Library) has implemented the Parallel.ForEach() such that it works with "expressed parallelism." Meaning, it does not guarantee that your delegates will run in multiple threads, but rather it checks to see if the host platform has multiple cores, and if true, only then does it distribute the work across the cores (essentially 1 thread per core). If the host system does not have multiple cores (getting harder and harder to find such a computer) then it will run your code sequenceally like a "regular" foreach loop would. Pretty cool stuff, frankly. Normally I would do something like the following to place my long running operation on a background thread from the ThreadPool: ThreadPool.QueueUserWorkItem( new WaitCallback(targetMethod), new Object2PassIn() ); In a situation whereby the host computer only has a single core does the TPL's Parallel.ForEach() automatically place the invocation on a background thread? Or, should I manaully invoke any TPL calls from a background thead so that if I am executing from a single core computer at least that logic will be off of the GUI's dispatching thread? My concern is if I leave the TPL in charge of all this I want to ensure if it determines it's a single core box that it still marshalls the code that's inside of the Parallel.ForEach() loop on to a background thread like I would have done, so as to not block my GUI. Thanks for any thoughts or advice you may have ...

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  • Events + Adapter Pattern

    - by Stretto
    I have an adapter pattern on a generic class that essentially adapts between types: class A<T> { event EventHandler e; } class Aadapter<T1, T2> : A<T1> { A<T2> a; Aadapter(A<T2> _a) { a = _a; } } The problem is that A contains an event. I effectively want all event handlers assigned to Adapter to fall through to a. It would be awesome if I could assign the a's event handler to adapter's event handler but this is impossible? The idea here is that A is almost really just A but we need a way to adapt the them. Because of the way event's work I can't how to efficiently do it except manually add two event handlers and when they are called they "relay" the to the other event. This isn't pretty though and it would seem much nicer if I could have something like class A<T> { event EventHandler e; } class Aadapter<T1, T2> : A<T1> { event *e; A<T2> a; Aadapter(A<T2> _a) { a = _a; e = a.e; } } in a sense we have a pointer to the event that we can assign a2's event to. I doubt there is any simple way but maybe someone has some idea to make it work. (BTW, I realize this is possible with virtual events but I'd like to avoid this if at all possible)

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  • What techniques do you use for emitting data from the server that will solely be used in client side scripts?

    - by chuck
    Hi all, I never found an optimal solution for this problem so I am hoping that some of you out there have a few solutions. Let's say I need to render out a list of checkboxes and each checkbox has a set of additional data that goes with it. This data will be used purely in the context of javascript and jquery. My usual strategy is to render this data in hidden fields that are grouped in the same container as the checkbox. My rendered HTML will look something like this: <div> <input type="checkbox" /> <input type="hidden" class="genreId" /> <input type="hidden" class="titleId" /> </div> My only problem with this is that the data in the hidden fields get posted to the server when the form is submitted. For small amounts of data, this is fine. However, I frequently work with large datasets and a large amount of data is needlessly transferred. UPDATE: Before submitting this post, I just saw that I can add a "DISABLED" attribute to my input element to suppress the submission of data. Is this pretty much the best approach that I can take? Thanks

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  • When asked "How do I make a website?" how do you answer?

    - by Luke CK
    A (non-technical) friend of mine has asked me how to make a website. I get this question all the time. After a few questions I found out that she has an idea that could turn into a commercial site. I described three options to her: a) Get a book/enroll in a class/follow some online tutorials and learn how to do it. She's pretty smart and her personality seems like a good match for this sort of thing so I'm sure she could learn but she doesn't have a lot of time spare. Maybe if she started with one of those WYSIWYG editors at first? I stressed that this would take a longer than a couple of weekends of playing around. b) Hire someone to build it. Ranges from ultra cheap to ultra expensive, crappy to good and everything in between. I didn't mention sites like Rentacoder because she hasn't worked on a project like this before and doesn't know what to ask for. At this stage she'd likely ask for a Youtube-MySpace-Google for a few hundred bucks because she doesn't yet understand just how much is involved. c) Find someone technical and partner up with them. I explained that this can either work really well or be a disaster because she'd have to give up some of her ownership of the idea. How do you respond in these situations?

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  • Phonegap: Will my mobile app 'feel' faster or slower once ported to phonegap?

    - by user15872
    So I'm designing everything in mobile Safari and I know that phonegap is essentially a stripped webview but... Question: Will my application will run better in phonegap? (revised below) a)I imagine my navigation and core app will load faster as the scripts and images are on the hard drive. Is this True? b)I assume since they've been working on it for 2 years now that they may have made some optimizations to make it quicker than just an average safari window. Is this true? (Assuming both html5/js/css code bases are pretty much the same and app is running on iOS.) Update: Sorry, I meant to compare apples to slightly different apples. Question 1 revised: Will my app see any performance benefits running with in a phonegap environment vs standard mobile safari? (compare mobile - to mobile) 1b) In what ways, other than loading time has phonegap optimized performance over standard mobile safari? Follow ups: 1) Are there any pitfalls, other than large libraries, that may cause phonegap to suffer a serious performance hit vs stand mobile safari? 2) Can I mix native and webview rendering? (i.e the top half of my app is rendered in with html/css/js and the bottom half native)

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  • C# specifying generic delegate type param at runtime

    - by smerlin
    following setup, i have several generic functions, and i need to choose the type and the function identified by two strings at runtime. my first try looked like this: public static class FOOBAR { public delegate void MyDelegateType(int param); public static void foo<T>(int param){...} public static void bar<T>(int param){...} public static void someMethod(string methodstr, string typestr) { MyDelegateType mydel; Type mytype; switch(typestr) { case "int": mytype = typeof(int); break; case "double": mytype = typeof(double); break; default: throw new InvalidTypeException(typestr); } switch(methodstr) { case "foo": mydel = foo<mytype>; //error break; case "bar": mydel = bar<mytype>; //error break; default: throw new InvalidTypeException(methodstr); } for(int i=0; i<1000; ++i) mydel(i); } } since this didnt work, i nested those switchs (a methodstr switch inside the typestr switch or viceversa), but that solution is really ugly and unmaintainable. The number of types is pretty much fixed, but the number of functions like foo or bar will increase by high numbers, so i dont want nested switchs. So how can i make this working without using nested switchs ?

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  • sql queries slower than expected

    - by neubert
    Before I show the query here are the relevant table definitions: CREATE TABLE phpbb_posts ( topic_id mediumint(8) UNSIGNED DEFAULT '0' NOT NULL, poster_id mediumint(8) UNSIGNED DEFAULT '0' NOT NULL, KEY topic_id (topic_id), KEY poster_id (poster_id), ); CREATE TABLE phpbb_topics ( topic_id mediumint(8) UNSIGNED NOT NULL auto_increment ); Here's the query I'm trying to do: SELECT p.topic_id, p.poster_id FROM phpbb_topics AS t LEFT JOIN phpbb_posts AS p ON p.topic_id = t.topic_id AND p.poster_id <> ... WHERE p.poster_id IS NULL; Basically, the query is an attempt to find all topics where the number of times someone other than the target user has posted in is zero. In other words, the topics where the only person who has posted is the target user. Problem is that query is taking a super long time. My general assumption when it comes to SQL is that JOINs of any are super fast and can be done in no time at all assuming all relevant columns are primary or foreign keys (which in this case they are). I tried out a few other queries: SELECT COUNT(1) FROM phpbb_topics AS t JOIN phpbb_posts AS p ON p.topic_id = t.topic_id; That returns 353340 pretty quickly. I then do these: SELECT COUNT(1) FROM phpbb_topics AS t JOIN phpbb_posts AS p ON p.topic_id = t.topic_id AND p.poster_id <> 77198; SELECT COUNT(1) FROM phpbb_topics AS t JOIN phpbb_posts AS p ON p.topic_id = t.topic_id WHERE p.poster_id <> 77198; And both of those take quite a while (between 15-30 seconds). If I change the < to a = it takes no time at all. Am I making some incorrect assumptions? Maybe my DB is just foobar'd?

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  • Implementations details of drag and drop of file path in cocoa.

    - by foo
    Hi, I'm trying to get a part of my window to react to drag and drop. In this case to copy the file path to the file being dropped on the view. I have looked over some documentation but I still have some problems to see exactly where I should implement my methods for drag and drop. I have seen some examples but almost all of them assumes that I want to drop an image on the view. I'm pretty new to cocoa and Xcode so, I have some problems with seeing the exact relation between interface builder and the generated code. I have created a subclass to NSView, called drop zone like this: #import <Cocoa/Cocoa.h> @interface dropZone : NSView { } @end I then use an NSRect to color it grey like this: #import "dropZone.h" @implementation dropZone - (void)drawRect:(NSRect)rect { NSRect bounds = [self bounds]; [[NSColor grayColor] set]; [NSBezierPath fillRect:bounds]; } @end I then drag this class to my window in interface builder. But I will need to implement the registerForDraggingTypes method, but where? I have also seen a convenience method in the Apple docs for file paths like this: dragFile:fromRect:slideBack:event: that might work.

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  • Change class of parent div if radio input checked

    - by xxstevenxo
    I've been searching and searching google for answers to my question but have been unsuccessful so far. I'm hoping one of you guys could give me some assistance. I have 10 divs with the class name "dividend" holding a table with the classname/id of "container" then two smaller tables inside that. Within the container table at the bottom is a hidden radio button with the name "page1". I wrote an onClcick for the container table so the user can select the whole table instead of the radio button, but not I'm trying to change the style of the selected container so the users know they have selected it. I have tried a few different methods and I'm able to change the style to the new class by just writing document.getElementById('container').className = 'selected'; But because all 10 divs share the same name it will only change the style of the first element it finds. So I tried writing this loop to check if there are any selected radios in the document then to change the else name the style as the default. I'm sure its something stupid but I'm pretty stumped atm.. Any help would be appreciated. Thanks. selected = function () { var divs = document.getElementByTagName('DIV'), div, tbl, rad, stat, i; for (i = 0; i < divs.length; i++) { div = divs.id; if (div == 'dividend') { tbl = div.getElementById('container'); rad = tbl.getElementByTagName('INPUT'); if (rad.checked = true) { tbl.className = 'selected'; } } } };

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  • Using a Data Management Singleton

    - by Dan Ray
    Here's my singleton code (pretty much boilerplate): @interface DataManager : NSObject { NSMutableArray *eventList; } @property (nonatomic, retain) NSMutableArray *eventList; +(DataManager*)sharedDataManager; @end And then the .m: #import "DataManager.h" static DataManager *singletonDataManager = nil; @implementation DataManager @synthesize eventList; +(DataManager*)sharedDataManager { @synchronized(self) { if (!singletonDataManager) { singletonDataManager = [[DataManager alloc] init]; } } NSLog(@"Pulling a copy of shared manager."); return singletonDataManager; } So then in my AppDelegate, I load some stuff before launching my first view: NSMutableArray *eventList = [DataManager sharedDataManager].eventList; .... NSLog(@"Adding event %@ to eventList", event.title); [eventList addObject:event]; NSLog(@"eventList now has %d members", [eventList count]); [event release]; As you can see, I've peppered the code with NSLog love notes to myself. The output to the Log reads like: 2010-05-10 09:08:53.355 MyApp[2037:207] Adding event Woofstock Music Festival to eventList 2010-05-10 09:08:53.355 MyApp[2037:207] eventList now has 0 members 2010-05-10 09:08:53.411 MyApp[2037:207] Adding event Test Event for Staging to eventList 2010-05-10 09:08:53.411 MyApp[2037:207] eventList now has 0 members 2010-05-10 09:08:53.467 MyApp[2037:207] Adding event Montgomery Event to eventList 2010-05-10 09:08:53.467 MyApp[2037:207] eventList now has 0 members 2010-05-10 09:08:53.524 MyApp[2037:207] Adding event Alamance County Event For June to eventList 2010-05-10 09:08:53.524 MyApp[2037:207] eventList now has 0 members ... What gives? I have no errors getting to my eventList NSMutableArray. But I addObject: fails silently?

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  • Trouble with go tour crawler exercise

    - by David Mason
    I'm going through the go tour and I feel like I have a pretty good understanding of the language except for concurrency. On slide 71 there is an exercise that asks the reader to parallelize a web crawler (and to make it not cover repeats but I haven't gotten there yet.) Here is what I have so far: func Crawl(url string, depth int, fetcher Fetcher, ch chan string) { if depth <= 0 { return } body, urls, err := fetcher.Fetch(url) if err != nil { ch <- fmt.Sprintln(err) return } ch <- fmt.Sprintf("found: %s %q\n", url, body) for _, u := range urls { go Crawl(u, depth-1, fetcher, ch) } } func main() { ch := make(chan string, 100) go Crawl("http://golang.org/", 4, fetcher, ch) for i := range ch { fmt.Println(i) } } The issue I have is where to put the close(ch) call. If I put a defer close(ch) somewhere in the Crawl method, then I end up writing to a closed channel in one of the spawned goroutines, since the method will finish execution before the spawned goroutines do. If I omit the call to close(ch), as is shown in my example code, the program deadlocks after all the goroutines finish executing but the main thread is still waiting on the channel in the for loop since the channel was never closed.

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  • Implementing IEnumeralbe on Non-Listed Items

    - by Stacey
    I have a class that contains a static number of objects. This class needs to be frequently 'compared' to other classes that will be simple List objects. public partial class Sheet { public Item X{ get; set; } public Item Y{ get; set; } public Item Z{ get; set; } } the items are obviously not going to be "X" "Y" "Z", those are just generic names for example. The problem is that due to the nature of what needs to be done, a List won't work; even though everything in here is going to be of type Item. It is like a checklist of very specific things that has to be tested against in both code and runtime. This works all fine and well; it isn't my issue. My issue is iterating it. For instance I want to do the following... List<Item> UncheckedItems = // Repository Logic Here. UncheckedItems contains all available items; and the CheckedItems is the Sheet class instance. CheckedItems will contain items that were moved from Unchecked to Checked; however due to the nature of the storage system, items moved to Checked CANNOT be REMOVED from Unchecked. I simply want to iterate through "Checked" and remove anything from the list in Unchecked that is already in "Checked". So naturally, that would go like this with a normal list. foreach(Item item in Unchecked) { if( Checked.Contains(item) ) Unchecked.Remove( item ); } But since "Sheet" is not a 'List', I cannot do that. So I wanted to implement IEnumerable so that I could. Any suggestions? I've never implemented IEnumerable directly before and I'm pretty confused as to where to begin.

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  • Error: undefined method `contact' for nil:NilClass

    - by user275801
    I have a ruby/rails/hobo system that someone wrote a couple years ago, that I need to port to the latest version of ruby/rails/hobo. It seems that ruby doesn't care about backward compatibility, so code that used to work in the old app doesn't work anymore: In the observation.rb model file, the old app has this: belongs_to :survey has_one :site, :through => :survey def create_permitted? acting_user == self.survey.contact or acting_user.administrator? end survey.rb model file has this: belongs_to :contact, :class_name => 'User', :creator => true Unfortunately the code in observation.rb doesn't work under the new ruby/rails/hobo, and it gives me the error: NoMethodError in Observations#index Showing controller: observations; dryml-tag: index-page where line #1 raised: undefined method `contact' for nil:NilClass Extracted source (around line #1): 0 Rails.root: /home/simon/ruby/frogwatch2 Application Trace | Framework Trace | Full Trace app/models/observation.rb:48:in `create_permitted?' How should the "create_permitted" method be changed? I'm finding that the documentation for ruby/rails/hobo is pretty atrocious (which is fair enough as it is free software). Also I don't even know how to begin searching for this on google (i've been trying for days). Please help! :)

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  • Why is my view controllers view not quadratic?

    - by mystify
    I created an UIViewController subclass, and figured out that the default implementation of -loadView in UIViewController will ignore my frame size settings in a strange way. To simplify it and to make sure it's really not the fault of my code, I did a clean test with a plain instance of UIViewController directly, rather than making a subclass. The result is the same. I try to make an exactly quadratic view of 320 x 320, but the view appears like 320 x 200. iPhone OS 3.0, please check this out: UIViewController *ts = [[UIViewController alloc] initWithNibName:nil bundle:nil]; ts.view.frame = CGRectMake(0.0f, 0.0f, 320.0f, 320.0f); ts.view.backgroundColor = [UIColor cyanColor]; [self.view addSubview:ts.view]; like you can see, I do this: 1) Create a UIViewController instance 2) Set the frame of the view to a quadratic dimension of 320 x 320 3) Give it a color, so I can see it 4) Added it as a subview. Now the part, that's even more strange: When I make my own implementation of -loadView, i.e. if I put this code in there like this: - (void)loadView { UIView *v = [[UIView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, 320.0f)]; v.backgroundColor = [UIColor cyanColor]; self.view = v; [v release]; } then it looks right. Now lets think about that: In the first example, I do pretty much exactly the same, just that I let UIViewController create the view on it's own, and then take it over in order to change it's frame. Right? So why do I get this strange error? Right now I see no other way of messing around like that to correct this wrong behavior. I did not activate anything like clipsToBounds and there's no other code touching this.

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  • Preview of code-only WPF controls in VS2010 - how?

    - by Christian
    Hi, I hope I am able to illustrate the problem using a lot of images. First of all, I was no real fan of XAML (Silverlight issues, crashes in Preview, and so on...) Now, with VS2010 the situation has become better. There are still a lot of things I like better in code, but I also want a preview in my VS. So, take a look at the following control: It is really simple, a todo details list. The first screenshot shows the code of the control, pretty straighforward: There is no XAML, so obviously no preview. Of course, I could encapsulate it in another control, like shown in the next screenshot: But, in that case I have an additional file I do not want or need. So I had the idea to move the init stuff inside the contructor of a XAML control. For simplicity, I used simple elements. But they do not show up in the preview... Finally, I know I could use the controls in other parts of my app when creating UIs. But I am using layout manager, PRISM and a lot of other stuff, so I just want an easy preview of some specific control I created (without having to have a XAML wrapper file for each control) Thanks for help, and sorry for the post structure, but I though with images it is better to understand... Chris

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  • How do I select column(s) by their "numeric" position in a table?

    - by DulcimerDude
    I am trying to select columns by their "x" position in the table. DBI my $example = $hookup->prepare(qq{SELECT This,That,Condition,"I also want COLUMN-10" FROM tbl LIMIT ? ?}); ###column_number=10 ordinal_position?? $example->execute('2','10') or die "Did not execute"; Is this possible or do I need to run another single select to just that column? One problem I encountered was with a col named "Condition". For some reason, when I tried to select Condition the execute would die. I never attempted but, What if the column name was SELECT? Another note is the table is 75 cols wide and I only need 50 of them. The Col names are pretty verbose so, I would like to just call them by their "position". This would also allow the col names to be changed in the future without having to change the select statement. I am quite the newbie so please explain any answers down to my level. Thanks for any assistance..

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  • Layout question with BlackBerry IDE FieldManagers; how to emulate HTML's rowspan

    - by canadiancreed
    Hello all I'm trying to create a page where a list of items are displayed in a row where there are multiple columns on the left, but only one on the right, encased within a horizontialFieldManager. Currently I have the following code to attempt to do the following: VerticalFieldManager mainScreenManager = new VerticalFieldManager(); mainScreenManager.add(titleField); for (int i = 0; i < 10; i++) { HorizontalFieldManager itemAreaManager = new HorizontalFieldManager(); VerticalFieldManager itemTextFieldsAreaManager = new VerticalFieldManager(); itemTextFieldsAreaManager.add(new RichTextField(contentArticleTitle[i])); itemTextFieldsAreaManager.add(new RichTextField(contentArticleDate[i])); itemTextFieldsAreaManager.add(new SeparatorField()); itemAreaManager.add(itemTextFieldsAreaManager); itemAreaManager.add(new ButtonField("", 0)); mainScreenManager.add(itemAreaManager); }; add(mainScreenManager); Now the issue I'm experiencing is probably obvious to those familiar with managers; the horizontialFieldManager has the first item added to it consuming the entire width available, thereby never showing the button. What I'm wondering is how can I tell this in an extended class to only take up a certain percentage of the available width? I've tried subLayout and setting the width to be a certain amount, but it will just show the button instead of the text (pretty much same problem, just reversed)

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  • java: assigning object reference IDs for custom serialization

    - by Jason S
    For various reasons I have a custom serialization where I am dumping some fairly simple objects to a data file. There are maybe 5-10 classes, and the object graphs that result are acyclic and pretty simple (each serialized object has 1 or 2 references to another that are serialized). For example: class Foo { final private long id; public Foo(long id, /* other stuff */) { ... } } class Bar { final private long id; final private Foo foo; public Bar(long id, Foo foo, /* other stuff */) { ... } } class Baz { final private long id; final private List<Bar> barList; public Baz(long id, List<Bar> barList, /* other stuff */) { ... } } The id field is just for the serialization, so that when I am serializing to a file, I can write objects by keeping a record of which IDs have been serialized so far, then for each object checking whether its child objects have been serialized and writing the ones that haven't, finally writing the object itself by writing its data fields and the IDs corresponding to its child objects. What's puzzling me is how to assign id's. I thought about it, and it seems like there are three cases for assigning an ID: dynamically-created objects -- id is assigned from a counter that increments reading objects from disk -- id is assigned from the number stored in the disk file singleton objects -- object is created prior to any dynamically-created object, to represent a singleton object that is always present. How can I handle these properly? I feel like I'm reinventing the wheel and there must be a well-established technique for handling all the cases.

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  • C++ bughunt - High-score insertion in a vector crashes the program

    - by Francisco P.
    Hello, everyone! I have a game I'm working on. My players are stored in a vector, and, at the end of the game, the game crashes when trying to insert the high-scores in the correct positions. Here's what I have (please ignore the portuguese comments, the code is pretty straightforward :P): //TOTAL_HIGHSCORES is the max. number of hiscores that i'm willing to store. This is set as 10. bool Game::updateHiScores() { bool stopIterating; bool scoresChanged = false; //Se ainda nao existirem TOTAL_HISCORES melhores pontuacoes ou se a pontuacao for melhor que uma das existentes for (size_t i = 0; i < players.size(); ++i) { //&& !(players[i].isAI()) if (players[i].getScoreValue() > 0 && (hiScores.size() < TOTAL_HISCORES || hiScores.back() < players[i].getScore())) { scoresChanged = true; if(hiScores.empty() || hiScores.back() >= players[i].getScore()) hiScores.push_back(players[i].getScore()); else { //Ciclo que encontra e insere a pontuacao no lugar desejado stopIterating = false; for(vector<Score>::iterator it = hiScores.begin(); it < hiScores.end() && !(stopIterating); ++it) { if(*it <= players[i].getScore()) { //E inserida na posicao 'it' o Score correspondente hiScores.insert(it, players[i].getScore()); //Verifica se o comprimento do vector esta dentro do desejado, se nao estiver, este e rectificado if (hiScores.size() > TOTAL_HISCORES) hiScores.pop_back(); stopIterating = true; } } } } } if (scoresChanged) sort(hiScores.begin(), hiScores.end(), higher); return scoresChanged; } What am I doing wrong here? Thanks for your time, fellas.

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  • How to delete a row from a typed dataset and save it to a database?

    - by Zingam
    I am doing this as a small project to learn about disconnected and connected models in .NET 4.0 and SQL Server 2008 R2. I have three tables: Companies (PK CompanyID) Addresses (PK AddressID, FK CompanyID) ContactPersons (PK ContactPersonID, FK CompanyID) CompanyID is assigned manually by the users. The other IDs are auto-generated. Companies has a one-to-many relationship with ContactPerson. I have set any changes to cascade. I display all records in Companies in a DataGridView and when a row is clicked, the corresponding records in ContactPersons are displayed in a second DataGridView. I have successfully implemented updating and inserting new records but I completely fail in my attempts to delete rows and save the changes to the database. I us a typed dataset. If I use this: DataRow[] contactPersonRows = m_SoldaCompaniesFileDataSet.ContactPersons.Select("ContactPersonID = " + this.m_CurrentContactPerson.ContactPersonID); m_SoldaCompaniesFileDataSet.ContactPersons.Rows.Remove(contactPersonRows[0]); The records are displayed properly in the DataGridView but are not saved in the database later. If I use this: DataRow row = m_SoldaCompaniesFileDataSet.ContactPersons.Rows.Find(this.m_CurrentContactPerson.ContactPersonID); row.Delete(); The records are set but I get an exeception: DeletedRowInaccessibleException, when I try to refresh the DataGridView. The exception pop-s up in the auto-generated dataset.design file. I am pretty much stuck at this point since yesterday. I cannot find anything anywhere that remotely resembles my problem. And I cannot understand actually what is going on.

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  • Add Hover display for table cell

    - by Jake
    I have a table, but it is not in a list format, meaning not a column/row format. I look for specific cells to add a hover event that displays a description of the cell. $("#TableID td").hover(function(){ //ifCellThatIWant $(this).append("<span>Message that was brought in</span>"); }, function(){ $(this).children().remove(); }); The problem is right now is that the hover displays a span(with info. inside) that I used jquery to append the span to the cell when mouseover, which expands the cell, which is an effect that I don't like or want. I'm Trying to have an out of the table look,but still be by the cell that triggered the event; because if the span has a lot of info. in it, expanding the cell dynamically will start to look pretty nasty. Also will help if I had some type of css direction on how will I make the display for the mouseover "description" span look nice. My mind thought is that a way to accomplish what I want is giver the appended span the position of my mouse cursor when hover, but not sure if its the right approach or what the syntax would look like.

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  • Recursion - Ship Battle

    - by rgorrosini
    I'm trying to write a little ship battle game in java. It is 100% academic, I made it to practice recursion, so... I want to use it instead of iteration, even if it's simpler and more efficient in most some cases. Let's get down to business. These are the rules: Ships are 1, 2 or 3 cells wide and are placed horizontally only. Water is represented with 0, non-hit ship cells are 1, hit ship cells are 2 and sunken ships have all it's cells in 3. With those rules set, I'm using the following array for testing: int[][] board = new int[][] { {0, 1, 2, 0, 1, 0}, {0, 0, 1, 1, 1, 0}, {0, 3, 0, 0, 0, 0}, {0, 0, 2, 1, 2, 0}, {0, 0, 0, 1, 1, 1}, }; It works pretty good so far, and to make it more user-friendly I would like to add a couple of reports. these are the methods I need for them: Given the matrix, return the amount of ships in it. Same as a), but separating them by state (amount of non-hit ships, hit and sunken ones). I will need a hand with those reports, and I would like to get some ideas. Remember it must be done using recursion, I want to understand this, and the only way to go is practice! Thanks a lot for your time and patience :).

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