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  • Workflow for academic research projects, one-step builds, and the Joel Test

    - by Steve
    Working alone on academic research sometimes breeds bad habits. With no one else reading my code, I would write a lot of throw-away code, and I would lose track of intermediate results which, weeks or months later, I wish I had retained. My recent attempts to make my personal workflow conform to the Joel Test raised interesting questions. Academic research has inherently different goals than industrial software development, and therefore some aspects of the Joel Test become less valid. Nevertheless, I find these steps to be still valuable for academic research: Do you use source control? Can you make a build in one step? Do you have an up-to-date schedule? Do you have a spec? Of particular use is the one-step build. I find myself more organized now that I have implemented the following "one-step build": In other words, I have a single script, build.py, that accepts Python code, data, and TeX as inputs. The outputs are results, figures, and a paper with all the results filled in. (Yes, I know "build" is probably not accurate in this context, but you get the idea.) By consolidating many small steps into one, I am not backtracking as much as I used to. ...but I'm sure there is still room for improvement. Question: For research projects, which steps of the Joel Test do you still value? Do you have a one-step build? If so, what does yours consist of, i.e., what inputs does it accept, and what output does it generate?

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  • Simple iPhone drawing app with Quartz 2D

    - by Mr guy 4
    I am making a simple iPhone drawing program as a personal side-project. I capture touches event in a subclassed UIView and render the actual stuff to a seperate CGLayer. After each render, I call [self setNeedsLayout] and in the drawRect: method I draw the CGLayer to the screen context. This all works great and performs decently for drawing rectangles. However, I just want a simple "freehand" mode like a lot of other iPhone applications have. The way I thought to do this was to create a CGMutablePath, and simply: CGMutablePathRef path; -(void)touchBegan { path = CGMutablePathCreate(); } -(void)touchMoved { CGPathMoveToPoint(path,NULL,x,y); CGPathAddLineToPoint(path,NULL,x,y); } -(void)drawRect:(CGContextRef)context { CGContextBeginPath(context); CGContextAddPath(context,path); CGContextStrokePath(context); } However, after drawing for more than 1 second, performance degrades miserably. I would just draw each line into the off-screen CGLayer, if it were not for variable opacity! The less-than-100% opacity causes dots to be left on the screen connecting the lines. I have looked at CGContextSetBlendingMode() but alas I cannot find an answer. Can anyone point me in the right direction? Other iPhone apps are able to do this with very good efficiency.

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  • Best ways to teach a beginner to program?

    - by Justin Standard
    Original Question I am currently engaged in teaching my brother to program. He is a total beginner, but very smart. (And he actually wants to learn). I've noticed that some of our sessions have gotten bogged down in minor details, and I don't feel I've been very organized. (But the answers to this post have helped a lot.) What can I do better to teach him effectively? Is there a logical order that I can use to run through concept by concept? Are there complexities I should avoid till later? The language we are working with is Python, but advice in any language is welcome. How to Help If you have good ones please add the following in your answer: Beginner Exercises and Project Ideas Resources for teaching beginners Screencasts / blog posts / free e-books Print books that are good for beginners Please describe the resource with a link to it so I can take a look. I want everyone to know that I have definitely been using some of these ideas. Your submissions will be aggregated in this post. Online Resources for teaching beginners: A Gentle Introduction to Programming Using Python How to Think Like a Computer Scientist Alice: a 3d program for beginners Scratch (A system to develop programming skills) How To Design Programs Structure and Interpretation of Computer Programs Learn To Program Robert Read's How To Be a Programmer Microsoft XNA Spawning the Next Generation of Hackers COMP1917 Higher Computing lectures by Richard Buckland (requires iTunes) Dive into Python Python Wikibook Project Euler - sample problems (mostly mathematical) pygame - an easy python library for creating games Create Your Own Games With Python ebook Foundations of Programming for a next step beyond basics. Squeak by Example Recommended Print Books for teaching beginners Accelerated C++ Python Programming for the Absolute Beginner Code by Charles Petzold

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  • jsf datatable lazy load filter and sorting

    - by darko petreski
    Hi, I have worked on several projects with a lot of data tables. The tables had sorting, filtering and paging of course on server side and with help of the db (all databases has implemented sording, filtering -where and limit the returned results). When workig on real application there are a thousands of even a millions rows. But I have seen several JSF dagatable components. They implement pagination, sorting and filtering on client side!! According to me this is very silly. This technology is called enterprise and they sort the data on the client side with java script! I have not seen any good JSF data grid that has build in features for sorting, filtering and lazy loading on the server side. Why is that? Am I looking in wrong direction or really there in no build support for this. Lately I am testing primefaces and lazy loading datatable. It really works fine, but the table i can only lazy load. If you add sort and filter then the problems begin. Conclusion: Is there any datatable JSF component than can perform lazy load pagination, and filtering and sorting on server side. If I need to implement my own solution thanks to the teams that made client side sorting and filtering, they are useless. Regards

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  • Nhibernate Guid with PK MySQL

    - by Andrew Kalashnikov
    Hello colleagues. I've got a question. I use NHibernate with MySql. At my entities I use Id(PK) for my business-logic usage and Guid(for replication). So my BaseDomain: public class BaseDomain { public virtual int Id { get; set; } public virtual Guid Guid { get; set; } public class Properties { public const string Id = "Id"; public const string Guid = "Guid"; } public BaseDomain() { } } My usage domain: public class ActivityCategory : BaseDomain { public ActivityCategory() { } public virtual string Name { get; set; } public new class Properties { public const string Id = "Id"; public const string Guid = "Guid"; public const string Name = "Name"; private Properties() { } } } Mapping: <class name="ActivityCategory, Clients.Core" table='Activity_category'> <id name="Id" unsaved-value="0" type="int"> <column name="Id" not-null="true"/> <generator class="native"/> </id> <property name="Guid"/> <property name="Name"/> </class> But when I insert my entity: [Test] public void Test() { ActivityCategory ac = new ActivityCategory(); ac.Name = "Test"; using (var repo = new Repository<ActivityCategory>()) repo.Save(ac); } I always get '00000000-0000-0000-0000-000000000000' at my Guid field. What should I do for generate right Guid. May be mapping? Thanks a lot!

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  • Activity Indicator display in Table View whilst row data is being fetched

    - by Tofrizer
    Hi All, I am navigating from tableview1.row to a tableview2 which has a LOT of rows being fetched. Given the load time is around 3 seconds, I want the navigation to slide into tableview2 as soon as the tableview1.row is selected, and then display a UIActivityIndicatorView above tableview2 whilst the data is fetched and then rendered in its underlying table view. Note, tableview2 is actually a subview of the parent UIView (as opposed to the parent being a UITableView). I've seen this post: http://stackoverflow.com/questions/2153653/activity-indicator-shold-be-displayed-when-navigating-from-uitableview1-to-uitabl ... which gives instructions to add the activity indicator start and stopAnimating calls around the data fetch into viewDidLoad of tableview2. Thing is, I'm not sure how the above solution could work as viewDidLoad runs and completes before tableview2 visibly slides into view. Separately, I also tried adding an activity indicator over tableview2 in IB and added the IBOutlet indicator's start/stop animating code into viewDidAppear. What happens is the data fetch runs and I can see the indicator spinning but at the end of the fetch, the table view is empty. Seems like viewDidAppear is too late to add data to the table view as cellForRowAtIndexPath etc has already fired. Can anyone please suggest any pointers? I could very well be missing something obvious here (its nearly 5am where I am and think my brain is mush). Should I re-trigger cellForRowAtIndexPath etc from viewDidAppear? Is the issue that my table view is a subview and not the parent view? Thanks

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  • How to insert inline content from one FlowDocument into another?

    - by Robert Rossney
    I'm building an application that needs to allow a user to insert text from one RichTextBox at the current caret position in another one. I spent a lot of time screwing around with the FlowDocument's object model before running across this technique - source and target are both FlowDocuments: using (MemoryStream ms = new MemoryStream()) { TextRange tr = new TextRange(source.ContentStart, source.ContentEnd); tr.Save(ms, DataFormats.Xaml); ms.Seek(0, SeekOrigin.Begin); tr = new TextRange(target.CaretPosition, target.CaretPosition); tr.Load(ms, DataFormats.Xaml); } This works remarkably well. The only problem I'm having with it now is that it always inserts the source as a new paragraph. It breaks the current run (or whatever) at the caret, inserts the source, and ends the paragraph. That's appropriate if the source actually is a paragraph (or more than one paragraph), but not if it's just (say) a line of text. I think it's likely that the answer to this is going to end up being checking the target to see if it consists entirely of a single block, and if it does, setting the TextRange to point at the beginning and end of the block's content before saving it to the stream. The entire world of the FlowDocument is a roiling sea of dark mysteries to me. I can become an expert at it if I have to (per Dostoevsky: "Man is the animal who can get used to anything."), but if someone has already figured this out and can tell me how to do this it would make my life far easier.

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  • InvalidCastException for two Objects of the same type

    - by LLEA
    hi, I have this weird problem that I cannot handle myself. A class in the model of my mvp-project designed as singleton causes an InvalidCastException. The source of error is found in this code line where the deserialised object is assigned to the instance variable of the class: engineObject = (ENGINE)xSerializer.Deserialize(str); It occurs whenever I try to add one of my UserControls to a Form or to a different UC. All of my UCs have a special presenter that access the above mentioned instance variable of the singleton class. This is what I get when trying to add a UC somewhere: 'System.TypeInitializationException: The type initializer for 'MVP.Model.EngineData' threw an exception. ---- System.InvalidCastException: [A]Engine cannot be cast to [B]Engine. Type A originates from 'MVP.Model, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' in the context 'LoadNeither' at location '[...]\AppData\Roaming\Microsoft\VisualStudio\9.0\ProjectAssemblies\uankw1hh01\MVP.Model.dll'. Type B originates from 'MVP.Model, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' in the context 'LoadNeither' at location '[...]\AppData\Roaming\Microsoft\VisualStudio\9.0\ProjectAssemblies\u_hge2de01\MVP.Model.dll'... So I somehow have two assemblies and they are not accessed from my project folder, but from a VS temp folder? I googled a lot and only found this: IronPython Exception: [A]Person cannot be cast to [B]Person. There is a solution offered, but first it concerns IronPhyton and second I don't know where to use it within my project? It would be just great, if u could help me out here :-) thx

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  • Instantiating a list of parameterized types, making beter use of Generics and Linq

    - by DanO
    I'm hashing a file with one or more hash algorithms. When I tried to parametrize which hash types I want, it got a lot messier than I was hoping. I think I'm missing a chance to make better use of generics or LINQ. I also don't like that I have to use a Type[] as the parameter instead of limiting it to a more specific set of type (HashAlgorithm descendants), I'd like to specify types as the parameter and let this method do the constructing, but maybe this would look better if I had the caller new-up instances of HashAlgorithm to pass in? public List<string> ComputeMultipleHashesOnFile(string filename, Type[] hashClassTypes) { var hashClassInstances = new List<HashAlgorithm>(); var cryptoStreams = new List<CryptoStream>(); FileStream fs = File.OpenRead(filename); Stream cryptoStream = fs; foreach (var hashClassType in hashClassTypes) { object obj = Activator.CreateInstance(hashClassType); var cs = new CryptoStream(cryptoStream, (HashAlgorithm)obj, CryptoStreamMode.Read); hashClassInstances.Add((HashAlgorithm)obj); cryptoStreams.Add(cs); cryptoStream = cs; } CryptoStream cs1 = cryptoStreams.Last(); byte[] scratch = new byte[1 << 16]; int bytesRead; do { bytesRead = cs1.Read(scratch, 0, scratch.Length); } while (bytesRead > 0); foreach (var stream in cryptoStreams) { stream.Close(); } foreach (var hashClassInstance in hashClassInstances) { Console.WriteLine("{0} hash = {1}", hashClassInstance.ToString(), HexStr(hashClassInstance.Hash).ToLower()); } }

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  • What algorithms do "the big ones" use to cluster news?

    - by marco92w
    I want to cluster texts for a news website. At the moment I use this algorithm to find the related articles. But I found out that PHP's similar_text() gives very good results, too. What sort of algorithms do "the big ones", Google News, Topix, Techmeme, Wikio, Megite etc., use? Of course, you don't know exactly how the algorithms work. It's secret. But maybe someone knows approximately the way they work? The algorithm I use at the moment is very slow. It only compares two articles. So for having the relations between 5,000 articles you need about 12,500,000 comparisons. This is quite a lot. Are there alternatives to reduce the number of necessary comparisons? [I don't look for improvements for my algorithm.] What do "the big ones" do? I'm sure they don't always compare one article to another and this 12,500,000 times for 5,000 news. It would be great if somebody can say something about this topic.

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  • When good programmers go bad!

    - by Ed Bloom
    Hi, I'm a team lead/dev who manages a team of 10 programmers. Most of them are hard working talented guys. But of late, I've got this one person who while highly talented and has delivered great work for me in the past, has just become completely unreliable. It's not his ability - that is not in question - he's proven that many times. He just looks bored now. Is blatantly not doing much work (despite a LOT of pressure being put on the team to meet tight deadlines etc.) He just doesn't seem to care and looks bored. I'm partially guilty for not having addressed this before now - I was afraid to have to lose a talented guy given the workload I've got on. But at this stage it's becoming a problem and affecting those around him. Can anyone spare their thoughts or words of wisdom on how I should go about dealing this. I want the talented AND motivated guy back. Otherwise he's gonna have to go. Thanks, Ed

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  • Exchanging strings (PChar) between a Freepascal compiled DLL and a Delphi compiled EXE

    - by John Riche
    After a lot of experimentations, I found a way to exchange PChar from a FreePascal compiled DLL with a Delphi compiled EXE. I'm in charge of both the DLL and EXE source code but one MUST BE in FreePascal and the other one in Delphi. My solution involves the following methods in the DLL: function GetAString(): PChar; var aString: string; begin aString := 'My String'; result := StrAlloc(length(aString) + 1); StrPCopy(result, aString); end; procedure FreeString(aString: PChar); begin StrDispose(aString); end; And from the Delphi EXE, to call the GetAString method, I need to Call the GetAString method, save the PChar to an actual Delphi String and call the FreeString method. Is this the best way of exchanging a string from a FreePascal DLL with a Delphi EXE ? Can I avoid the call to FreeString from Delphi ? And finally, if that's the correct solution, how will it behave with Delphi 2010 and the WideString by default: do I need to force WidePChar in FreePascal too ?

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  • Editing a UITextField inside a UITableViewCell fails

    - by Stephen Darlington
    In my application I have a UITextField inside a UITableViewCell. If I click inside the text field and add some text I find that if try to move the insertion point it works the first time but fails on subsequent attempts. I am completely unable to move the selection; no "magnifying glass" appears. Even more curious, this "setting" seems to be permanent until I restart the application. And it affects all UITextFields on that screen and not just the one that I originally tried to edit. If you want to see it yourself, try the "UICatalog" sample that comes with the iPhone SDK. Click "text fields" and then "edit" and play around with the text boxes. I've done a lot of digging on this but it's pretty hard to Google for! The best references I've found are on Apple's support board and MacRumors formum (both reference a solution that apparently used to work on iPhone 2.0 but does work not with contemporary versions -- I did try). My feeling that is that this is a bug in the OS, but I thought I'd throw this out to the SO crowd for a second opinion and to see if there are any workarounds. Any ideas? Following benzado's suggestion, I tried building my application using the 2.0, 2.1 and 2.2 SDKs. I got the same behaviour in all versions. (Actually, something related but not the same broke in 2.2 but that's probably another question!)

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  • jQuery slideToggle() Internet Explorer problem and jumpy animation

    - by UtothaX
    Hey yaa! I have a big problem with my jquery. I finally made it that my slidetoggle runs in firefox. The animation is a little bit jumpy in the end of the animation. I read a lot of workarounds, but somehow nothing helped me really. Perhaps anyone of you can rescue me out of this dilemma. The other bigger problem is that the hidden divs are unfortunately shown directly on start in internet explorer. I tested it in IE6&7. And the sliding effect is also very strange. Does anyone of you know if I have to give additional styling for IE??? Here is my site I am working on: http://www.haus-plan.de/%5F01%5FHausplan/ the red titles are slideable in the content area and the two Slide words on the right panel. I noticed that Internet Explorer runs the first Slide word on the right panel correctly. Here its div is first hidden and only shows up when we click and let it slide down. But for the other divs they are shown in the beginning which is very sh..... Please help meee....

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  • Python progression path - From apprentice to guru

    - by Morlock
    Hi all, I've been learning, working, and playing with Python for a year and a half now. As a biologist slowly making the turn to bio-informatics, this language has been a the very core of all the major contributions I have made in the lab. (bash and R scripts have helped some too. My C++ capabilities are very not functional yet). I more or less fell in love with the way Python permits me to express beautiful solutions and also with the semantics of the language that allows such a natural flow from thoughts to workable code. What I would like to know from you is your answer to a kind of question I have seldom seen in this or other forums. Let me sum up what I do NOT want to ask first ;) I don't want to know how to QUICKLY learn Python Nor do I want to find out the best way to get acquainted with the language Finally, I don't want to know a 'one trick that does it all' approach. What I do want to know your opinion about, is: What are the steps YOU would recommend to a Python journeyman, from apprenticeship to guru status (feel free to stop wherever your expertise dictates it), in order that one IMPROVES CONSTANTLY, becoming a better and better Python coder, one step at a time. The kind of answers I would enjoy (but feel free to surprise the readership :P ), is formatted more or less like this: Read this (eg: python tutorial), pay attention to that kind of details Code for so manytime/problems/lines of code Then, read this (eg: this or that book), but this time, pay attention to this Tackle a few real-life problems Then, proceed to reading Y. Be sure to grasp these concepts Code for X time Come back to such and such basics or move further to... (you get the point :) This process depicts an iterative Learn/Code cycle, and I really care about knowing your opinion on what exactly one should pay attention to, at various stages, in order to progress CONSTANTLY (with due efforts, of course). If you come from a specific field of expertise, discuss the path you see as appropriate in this field. Thanks a lot for sharing your opinions and good Python coding!

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  • Improve XPath efficiency for repeated, parameterized queries

    - by Chris Allan
    Hi, I am repeatedly performing the following XPath query (though parameterized by 'keywordText') around 40,000 times: String query = SystemGlobal.YAHOO_KEYWORDSSUBNODE + "/" + SystemGlobal.YAHOO_KEYWORDNODE + "[" + SystemGlobal.YAHOO_ATTRKEYPHRASE + "='" + keywordText + "']"; CachedXPathAPI cachedXPathAPI = new CachedXPathAPI(); NodeIterator nl = cachedXPathAPI.selectNodeIterator(doc.getElementsByTagName(SystemGlobal.YAHOO_KEYWORDSROOT).item(0), query); Node n; if ((n = nl.nextNode()) != null) { keyword.setKeywordId(Long.parseLong(cachedXPathAPI.selectSingleNode(n, SystemGlobal.YAHOO_ATTRKEYID).getTextContent())); keyword.setKeyPhrase(cachedXPathAPI.selectSingleNode(n, SystemGlobal.YAHOO_ATTRKEYPHRASE).getTextContent()); keyword.setStatus(mapStatus(cachedXPathAPI.selectSingleNode(n, SystemGlobal.YAHOO_ATTRSTATUS).getTextContent())); keyword.setCampaignId(Long.parseLong(cachedXPathAPI.selectSingleNode(n, "../../" + SystemGlobal.YAHOO_ATTRCAMPAIGNID).getTextContent())); keyword.setAdGroupId(Long.parseLong(cachedXPathAPI.selectSingleNode(n, "../" + SystemGlobal.YAHOO_ATTRADGROUPID).getTextContent())); On the first run of the script, all 40,000 runs of this piece of code will have nl.nextNode() == null, and everything runs quite quickly. However, on the following runs, when nl.nextNode() != null, then things slow down a lot - this takes around an additional 40min to run (whereas the first run takes maybe 1 minute). Oh, and the doc is constructed like so: InputSource in = new InputSource(new FileInputStream(filename)); DocumentBuilderFactory dfactory = DocumentBuilderFactory.newInstance(); dfactory.setNamespaceAware(true); doc = dfactory.newDocumentBuilder().parse(in); I tried including the following lines reportEvaluator = new XPathEvaluatorImpl(reportDoc); reportResolver = reportEvaluator.createNSResolver(reportDoc); and rather creating a NodeIterator, instead creating an XPathResult: XPathResult result = (XPathResult)reportEvaluator.evaluate(query, doc.getElementsByTagName(SystemGlobal.YAHOO_KEYWORDSROOT).item(0), reportResolver, XPathResult.UNORDERED_NODE_ITERATOR_TYPE, null); however this ran even slower Is there a way in which I can speed up the running of this script? I have seen references to precompiled queries, though I haven't seen many actual details. Also, as seen in the code, I am using CachedXPathAPI, though the benefit for this case is not so great. Any help is much appreciated! Chris Allan

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  • NServiceBus Testing Framework and NAnt Issue?

    - by user344775
    Hi Guys, This is my first post here, and I'm new to NService Bus world. After play around for a couple days, and found that it's really powerful framework to creat service and easy to use. :) Now, I came across a small question. I created a project which uses NServiceBus, it got normal message handlers and Saga handlers. And also I created a couple tests around these with NServiceBus.Testing framework. It all works fine when I run the tests via ReSharper Test Runner works and NUnit console, they all works fine, but when I include them into NAnt build script, it throw the following exception: System.Reflection.ReflectionTypeLoadException : Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information. at System.Reflection.Module.GetTypesInternal(StackCrawlMark& stackMark) at System.Reflection.Assembly.GetTypes() at NServiceBus.Configure.<c_DisplayClass1.b__0(Assembly a) at System.Array.ForEach[T](T[] array, Action`1 action) at NServiceBus.Configure.With(Assembly[] assemblies) at NServiceBus.Configure.With(String probeDirectory) at NServiceBus.Configure.With() at NServiceBus.Testing.Test.Initialize() Any ideas? Thanks a lot.

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  • Slow Performance -- ASP .NET ASPNET_WP.EXE and CSC.EXE Running After Clicking Redirect Link

    - by Dan7el
    I click on a link from one page that does a redirect to another page (Response.Redirect(page.aspx)). The browser churns for about 30 seconds and the page displays. I'm trying to track down why it takes so long to load the page. The page hosts two other custom controls. I have commented out the lines of code for each and both controls, and the page still takes about 30 seconds to load. I've set breakpoints on the Page_Load event for each of the controls as well as page.aspx and it also takes about 30 seconds from clicking the link with the Response.Redirect to the first break point. I loaded up task manager and clicked on the link. I notice aspnet_wp.exe and csc.exe run during this 30 second time frame. I'm wondering if there are some sort of code-behind shinanigans going on while I'm waiting for the page to load. This only occurs the first time I click on the link. Afterwards, it's not as slow. I've googled but there's not a lot of useful information about this. Anyone have any ideas? Thanks, ---Dan---

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  • Try to use Window.FEATURU_CUSTOM_TITLE but got Exception:You cannot combine custom titles with other

    - by xueru
    I am trying to use a custom title to include an image button to the title bar. I got a lot of help form this post: http://stackoverflow.com/questions/2569753/android-adding-button-to-the-title-of-the-app, but could not get it work for my ListActivity. In a nutshell, following is what I have: I hide the titlebar in the AndroidManifest.xml The specify a relative layout for the custom title (workorder_list_titlebar.xml) My Activity Class looks like the following: public class WorkOrderListActivity extends ListActivity { String[] orders={"WO-12022009", "WO-12302009", "WO-02122010", "02152010"}; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_CUSTOM_TITLE); this.getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.workorder_list_titlebar); setContentView(R.layout.workorder_list); setListAdapter(new ArrayAdapter(this,R.layout.workorder_list, R.id.label,orders)); } } When I ran the app, I got AndroidRuntimeException: You cannot combine custom titles with other title features. Base on the stack trace, the exception was thrown by com.android.internal.policy.impl.PhoneWindow.requestFeature(PhoneWindow.java:183), that was triggered by setlistAdapter call. Does anyone have the same problem with ListActivity? Also once I manage to get this work, how do I attach listeners to the image button for it to do something? Thanks in advance.

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  • What's slowing for loops/assignment vs. C?

    - by Lee
    I have a collection of PHP scripts that are extremely CPU intensive, juggling millions of calculations across hundreds of simultaneous users. I'm trying to find a way to speed up the internals of PHP variable assignment, and looping sequences vs C. Although PHP is obviously loosely typed, is there any way/extension to specifically assign type (assign, not cast, which seems even more expensive) in a C-style fashion? Here's what I mean. This is some dummy code in C: #include <stdio.h> int main() { unsigned long add=0; for(unsigned long x=0;x<100000000;x++) { add = x*59328409238; } printf("x is %ld\n",add); } Pretty self-explanatory -- it loops 100 million times, multiples each iteration by an arbitrary number of some 59 billion, assigns it to a variable and prints it out. On my Macbook, compiling it and running it produced: lees-macbook-pro:Desktop lee$ time ./test2 x is 5932840864471590762 real 0m0.266s user 0m0.253s sys 0m0.002s Pretty darn fast! A similar script in PHP 5.3 CLI... <?php for($i=0;$i<100000000;$i++){ $a=$i*59328409238; } echo $a."\n"; ?> ... produced: lees-macbook-pro:Desktop lee$ time /Applications/XAMPP/xamppfiles/bin/php test3.php 5.93284086447E+18 real 0m22.837s user 0m22.110s sys 0m0.078s Over 22 seconds vs 0.2! I realize PHP is doing a heck of a lot more behind the scenes than this simple C program - but is there any way to make the PHP internals to behave more 'natively' on primitive types and loops?

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  • MVVM Madness: Commands

    - by JP
    I like MVVM. I don't love it, but like it. Most of it makes sense. But, I keep reading articles that encourage you to write a lot of code so that you can write XAML and don't have to write any code in the code-behind. Let me give you an example. Recently I wanted to hookup a command in my ViewModel to a ListView MouseDoubleClickEvent. I wasn't quite sure how to do this. Fortunately, Google has answers for everything. I found the following articles: http://blog.functionalfun.net/2008/09/hooking-up-commands-to-events-in-wpf.html http://joyfulwpf.blogspot.com/2009/05/mvvm-invoking-command-on-attached-event.html http://sachabarber.net/?p=514 http://geekswithblogs.net/HouseOfBilz/archive/2009/08/27/adventures-in-mvvm-ndash-binding-commands-to-any-event.aspx http://marlongrech.wordpress.com/2008/12/13/attachedcommandbehavior-v2-aka-acb/ While the solutions were helpful in my understanding of commands, there were problems. Some of the aforementioned solutions rendered the WPF designer unusable because of a common hack of appending "Internal" after a dependency property; the WPF designer can't find it, but the CLR can. Some of the solutions didn't allow multiple commands to the same control. Some of the solutions didn't allow parameters. After experimenting for a few hours I just decided to do this: private void ListView_MouseDoubleClick(object sender, MouseButtonEventArgs e) { ListView lv = sender as ListView; MyViewModel vm = this.DataContext as MyViewModel; vm.DoSomethingCommand.Execute(lv.SelectedItem); } So, MVVM purists, please tell me what's wrong with this? I can still Unit test my command. This seems very practical, but seems to violate the guideline of "ZOMG... you have code in your code-behind!!!!" Please share your thoughts. Thanks in advance.

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  • How to speed up WPF programs?

    - by Sam
    I love programming with and for Windows Presentation Framework. Mostly I write browser-like apps using WPF and XAML. But what really annoys me is the slowness of WPF. A simple page with only a few controls loads fast enough, but as soon as a page is a teeny weeny bit more complex, like containing a lot of data entry fields, one or two tab controls, and stuff, it gets painful. Loading of such a page can take more than one second. Seconds, indeed, especially on not so fast computers (read: the customers computers) it can take ages. Same with changing values on the page. Everything about the WPF UI is somehow sluggy. This is so mean! They give me this beautiful framework, but make it so excruciatingly slow so I'll have to apologize to our customers all the time! My Question: How do you speed up WPF? How do you profile bottlenecks? How do you deal with the slowness? Since this seems to be an universal problem with WPF, I'm looking for general advice, useful for many situations and problems. Some other related questions: What tools do you use for WPF development Tools to develop WPF or Silverlight applications

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  • Metaprogramming - self explanatory code - tutorials, articles, books

    - by elena
    Hello everybody, I am looking into improving my programming skils (actually I try to do my best to suck less each year, as our Jeff Atwood put it), so I was thinking into reading stuff about metaprogramming and self explanatory code. I am looking for something like an idiot's guide to this (free books for download, online resources). Also I want more than your average wiki page and also something language agnostic or preferably with Java examples. Do you know of such resources that will allow to efficiently put all of it into practice (I know experience has a lot to say in all of this but i kind of want to build experience avoiding the flow bad decisions - experience - good decisions)? EDIT: Something of the likes of this example from the Pragmatic Programmer: ...implement a mini-language to control a simple drawing package... The language consists of single-letter commands. Some commands are followed by a single number. For example, the following input would draw a rectangle: P 2 # select pen 2 D # pen down W 2 # draw west 2cm N 1 # then north 1 E 2 # then east 2 S 1 # then back south U # pen up Thank you!

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  • WPF creating custom control - creating control like SpinBox extending TextBox

    - by veedoo
    Hi, What is the best way to extend a control? Lets choose for example SpinBox - we want to extend TextBox to SpinBox - just to add two buttons on the right side, which each one on click checks if Text property is a valid number and if it is increases or decreases the value by 1. Suposse that we have a lot of code using TextBox (Text, IsReadOnly properties and bindings etc.) so we want to replace TextBox by SpinBox without touching rest of the code. 1) we can inherit TextBox - so we have exactly the same interface, but how to add the buttons ?? 2) we can inherit from some layout control - eg. DockPanel - we can add buttons, but we lose TextBox interface. 3) after quick read about ControlTemplates I'm not sure, but I believe that we can add buttons and their logic using ControlTemplates 4) like about templates I'm not sure, but I hope we can inherit decorator class to create decorator with the buttons - we lose interface, but can add TextBox as a child I think that the best solutions is to combine 3) and 4) - create a decorator class and use it in a control template for TextBox. I would be grateful for your ideas and simple code how to implement 3 and 4, especially with code (c#), not xaml. Regards

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  • Get ListView Visible items

    - by Vincent Piel
    I have a ListView which might contains a lot of items, so it is virtualized and recycling items. It does not use sort. I need to refresh some value display, but when there are too many items, it is too slow to update everything, so I would like to refresh only the visible items. How could I get a list of all currently displayed items ? I tried to look into the ListView or in the ScrollViewer, but I still have no idea how to achieve this. The solution must NOT go through all items to test if they can be seen, because this would be too slow. I'm not sure code or xaml would be usefull, it is just a Virtualized/Recycling ListView with its ItemSource bound to an Array. Edit Answer : thanks to akjoshi, i found the way : get the ScrollViewer of the ListView (with a FindDescendant method, that you can do yourself with the VisualTreeHelper ). Then use its ScrollViewer.VerticalOffset : it is the number of the first item shown and ScrollViewer.ViewportHeight : it is the count of items shown. Rq : CanContentScroll must be true.

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