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  • Does it make a difference in performance if I use self.fooBar instead of fooBar?

    - by mystify
    Note: I know exactly what a property is. This question is about performance. Using self.fooBar for READ access seems a waste of time for me. Unnecessary Objective-C messaging is going on. The getters typically simply pass along the ivar, so as long as it's pretty sure there will be no reasonable getter method written, I think it's perfectly fine to bypass this heavy guy. Objective-C messaging is about 20 times slower than direct calls. So if there is some high-performance-high-frequency code with hundreds of properties in use, maybe it does help a lot to avoid unnessessary objective-c messaging? Or am I wasting my time thinking about this?

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  • UISearchbar issue

    - by hmthur
    I am trying to add a UISearchbar to table header view. I have the icon in nib and have connected the outlets. Now in viewDidLoad, I am writing self.tableView.tableHeaderView = searchbar If i create a local var inside viewDidLoad, it shows up. But not the outlet or ivar one. But for some reason, the UISearchbar does not get displayed in the table. I am not sure what the issue is. Can a UISearchbar not be set in viewDidLoad OR is it something else? Please help.

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  • Objective-C NSString Assignment Problem

    - by golfromeo
    In my Cocoa application, in the header file, I declare a NSString ivar: NSString *gSdkPath; Then, in awakeFromNib, I assign it to a value: gSdkPath = @"hello"; Later, it's value is changed in the code: gSdkPath = [NSString stringWithString:[folderNames objectAtIndex:0]]; (the object returned from objectAtIndex is an NSString) However, after this point, in another method when I try to NSLog() (or do anything with) the gSdkPath variable, the app crashes. I'm sure this has something to do with memory management, but I'm beginning with Cocoa and not sure exactly how this all works. Thanks for any help in advance.

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  • Ruby on Rails- :symbols, @iVars and "strings" - oh my!

    - by Meltemi
    New to Rails and trying to get my head around when/why to use :symbols, @ivars , "strings" within the framework. I think I understand the differences between them conceptually only one :symbol instance per project one @ivar per instance multiple "strings" - as they are created whenever referenced (?) Feel free to correct me! The main confusion comes from understanding the rules & conventions of what Rails expects - where and WHY? I'm sure there's an "Ah ha!" moment coming but I haven't had it yet...as it seems pretty arbitrary to me (coming from C/Obj-C). -thx

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  • Casting Class into String and Vice Versa in JAVA

    - by topgun_ivard
    I have a program in which I need to store a Class object into memory by casting it into String. Is it possible to convert the String back into the original Class so that I can use that class variables? I am doing this in JAVA. Example: test.java class hello{ public String h1; public String h2; } public class test { public static void main(String[] args) { hello h = new hello(); h.h1 = "hello"; h.h2 = "world"; String s = h.toString(); System.out.println("Print s : "+s); // Now I need to convert String s into type hello so that // I can do this: // (hello)s.h1; // (hello)s.h2; } } NOTE: this is not a homework, this is a personal project and I would be grateful if anyone can help! Thanks! Ivar

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  • EXC_BAD_ACCESS when returning a CGRect in iPhone

    - by pabloruiz55
    I have a class which must return a CGRect from one of its methods: -(CGRect)myRect { CGRect rect = CGRectMake(self.mySprite.position.x,self.mySprite.position.y,self.mySprite.textureRect.size.width, self.mySprite.textureRect.size.height); return rect; } I get an exc_bad_access as soon as i try to access the mySprite ivar. Thing is if i call it, the instance variable mySprite is full of garbage. BUT if i change the function to return void, self.mySprite does contain the correct data. -(void)myRect { CGRect rect = CGRectMake(self.mySprite.position.x,self.mySprite.position.y,self.mySprite.textureRect.size.width, self.mySprite.textureRect.size.height); return rect; } that does not crash when accessing mySprite...

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  • A few questions about integrating AudioKinetic Wwise and Unity

    - by SaldaVonSchwartz
    I'm new to Wwise and to using it with Unity, and though I have gotten the integration to work, I'm still dealing with some loose ends and have a few questions: (I'm on Unity 4.3 as of now but I think it shouldn't make any difference) The base path: The Wwise documentation implies you set this in the AkGlobalSoundEngineInitializer basePath public ivar, which is exposed to the editor. However, I found that this variable is not really used. Instead, the path is hardcoded to /Audio/GeneratedSoundBanks in AkBankPath. I had to modify both scripts to actually look in the path that I set in the editor property. What's the deal with this? Just sloppyness or am I missing something? Also about paths: since I'm on Mac, I'm using Unity natively under OS X and in tadem, the Wwise authoring tool via VMWare and I share the OS X Unity project folder so I can generate the soundbanks into the assets folder. However, the authoring tool (downloaded the latest one for Windows) doesn't automatically generate any "platform-specific" subfolders for my wwise files. That is, again, the Unity integration scripts assume the path to be /Audio/GeneratedSoundBanks/<my-platform>/ which in my case would be Mac (I set the authoring tool to generate for Mac). The documentation says wwise will automatically generate the platform-specific folders but it just dumps all the stuff in GeneratedSoundBanks. Am I missing some setting? cause right now I just manually create the /Mac folder. The C# methods AkSoundEngine.PostEvent and AkSoundEngine.LoadBank for instance, have a few overloads, including ones where I can refer to the soundbanks or events by their ID. However, if I try to use these, for instance: AkSoundEngine.LoadBank(, AkSoundEngine.AK_DEFAULT_POOL_ID) where the int I got from the .h header, I get Ak_Fail. If I use the overloads that reference the objects by string name then it works. What gives? Converting the ID header to C#: The integration comes with a C# script that seems to fork a process to call Python in turn to covert the C++ header into a C# script. This always fails unless I manually execute the Python script myself from outside Unity. Might be a permissions thing, but has anyone experienced this? The Profiler: I set up the Unity player to run in the background and am using the "Profile" version of the plugin. However, when I start the Unity OS X standalone app, the profiler in VMWare does not see it. This I'm thinking might just be that I'm trying to see a running instance of the sound engine inside an OS X binary from a Windows virtual machine. But I'm just wondering if anyone has gotten the Windows profiler to see an OS X Unity binary. Different versions of the integration plugin: It's not clear to me from the documentation whether I have to manually (or write a script to do it) remove the "Profile" version and install the "Release" version when I'm going to do a Release build or if I should install both version in Unity and it'll select the right one. Thanks!

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  • Debugging NSoperation BAD ACCESS within graphics context

    - by Joe
    I tried everything to debug this one but I can't get to the bottom of it. This code lives in a subclass of NSOperation which is processed from a queue: (borders is an ivar NSArray containing 5 UIimage objects) NSMutableArray *images = [[NSMutableArray alloc] init]; for (unsigned i = 0; i < 5; i++) { CGSize size = CGSizeMake(60, 60); UIGraphicsBeginImageContext(size); CGPoint thumbPoint = CGPointMake(6, 6); [controller.image drawAtPoint:thumbPoint]; CGPoint borderPoint = CGPointMake(0, 0); [[borders objectAtIndex:i] drawAtPoint:borderPoint]; [images addObject:UIGraphicsGetImageFromCurrentImageContext()]; UIGraphicsEndImageContext(); } [images release]; The code works fine most of the time but when I push the iphone by access subviews and pressing lots of buttons on the UI I either get this exception which is trapped by the operation: Exception Load view: *** -[NSCFArray insertObject:atIndex:]: attempt to insert nil or I get this: Program received signal: “EXC_BAD_ACCESS”. The exception is caused because UIGraphicsGetImageFromCurrentImageContext() return nil. I don't know how to debug the EXC_BAD_ACCESS but I'm guessing that this error (in fact both of these errors) is caused by low memory. The debugger stops at the line: [controller.image drawAtPoint:thumbPoint]; As I mentioned I've trapped the exception so I can live with that but the EXC_BAD_ACCESS is more serious. IF this is memory related how can I tell and is it possible to increase the memory available to NSOperation?

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  • how to extend a protocol for a delegate in objective C, then subclass an object to require a conform

    - by fess .
    I want to subclass UITextView, and send a new message to the delegate. So, I want to extend the delegate protocol, What's the correct way to do this? I started out with this: interface: #import <Foundation/Foundation.h> @class MySubClass; @protocol MySubClassDelegate <UITextViewDelegate> - (void) MySubClassMessage: (MySubClass *) subclass; @end @interface MySubClass : UITextView { } @end implementation: #import "MySubClass.h" @implementation MySubClass - (void) SomeMethod; { if ([self.delegate respondsToSelector: @selector (MySubClassMessage:)]) { [self.delegate MySubClassMessage: self]; } } @end however with that I get the warning: '-MySubClassMessage:' not found in protocol(s). I had one way working where I created my own ivar to store the delegate, then also stored the delegate using [super setDelegate] but that seemed wrong. perhaps it's not. I know I can just pass id's around and get by, but My goal is to make sure that the compiler checks that any delegate supplied to MySubClass conforms to MySubClassDelegate protocol. To further clairfy: @interface MySubClassTester : NSObject { } @implementation MySubClassTester - (void) one { MySubClass *subclass = [[MySubClass alloc] init]; subclass.delegate = self; } @end will produce the warning: class 'MySubClassTester' does not implement the 'UITextViewDelegate' protocol I want it to produce the warning about not implementing 'MySubClassDelegate' protocol instead. Thanks, a bunch. (thanks brad)

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  • OpenGL behaving strangely

    - by Mk12
    OpenGL is acting very strangely for some reason. In my subclass of NSOpenGLView, I have the following code in -prepareOpenGL: - (void)prepareOpenGL { GLfloat lightAmbient[] = { 0.5f, 0.5f, 0.5f, 1.0f }; GLfloat lightDiffuse[] = { 1.0f, 1.0f, 1.0f, 1.0f }; GLfloat lightPosition[] = { 0.0f, 0.0f, 2.0f }; quality = 0; zCoord = -6; [self loadTextures]; glEnable(GL_LIGHTING); glEnable(GL_TEXTURE_2D); glShadeModel(GL_SMOOTH); glClearColor(0.2f, 0.2f, 0.2f, 0.0f); glClearDepth(1.0f); glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LEQUAL); glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); glLightfv(GL_LIGHT1, GL_AMBIENT, lightAmbient); glLightfv(GL_LIGHT1, GL_DIFFUSE, lightDiffuse); glLightfv(GL_LIGHT1, GL_POSITION, lightPosition); glEnable(GL_LIGHT1); gameState = kGameStateRunning; int i = 0; // HERE ******** [NSTimer scheduledTimerWithTimeInterval:0.03f target:self selector:@selector(processKeys) userInfo:nil repeats:YES]; // Synchronize buffer swaps with vertical refresh rate GLint swapInt = 1; [[self openGLContext] setValues:&swapInt forParameter:NSOpenGLCPSwapInterval]; // Setup and start displayLink [self setupDisplayLink]; } I wanted to assign the timer that processes key input to an ivar so that I could invalidate it when the game is paused (and reinstantiate it on resume), however when I did that (as apposed to leaving it at [NSTimer scheduledTimer…), OpenGL doesn't display the cube I draw. When I take it away, it's fine. So i tried just adding a harmless statement, int i = 0; (maked // HERE *******), and that makes the lighting not work! When I take it away, everything is fine, but when I put it back, everything is dark. Can someone come up with a rational explanation for this? Thanks.

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  • CGContext problems

    - by Peyman
    Hi I have a CALayer tree hierarchy A B C D where A is the view's root layer (and I create and add B,C and D layers. I am using the same delegate method `- (void) drawLayer:(CALayer *) theLayer inContext:(CGContextRef)context to provide content to each of these layers (implemented through a switch statement in the above method). At initiation A's content is drawn (A.contents) sequentially through these methods `- (void) drawLayer:(CALayer *) theLayer inContext:(CGContextRef)context -(void) drawCircle:(CALayer *) theLayer inContext:(CGContextRef)context where drawCircle does CGContextSaveGState(context); / draws circle and other paths here / CGContextRestoreGState(context); CGImageRef contentImage = CGBitmapContextCreateImage(context); theLayer.contents = (id) contentImage; CGImageRelease(contentImage); (i.e I save the Context, do the drawing, restore the context, make a bitmap of the context, update the layer's contents, in this case A's, then release the contentimage). When the user then clicks somewhere in the circle at touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event delegate method I then try to paint the content of B by (still in touchesEnded:) CGContextRef context = UIGraphicsGetCurrentContext(); [self drawLayer:self.B inContext:context]; [self.B setNeedsDisplay]; the setNeedsDisplay call the delegate - drawLayer:(CALayer *) theLayer inContext:(CGContextRef)context again but this time the switch statement (using a layer flag) calls [self drawCircle:theLayer inContext:context]; with color red. The problem I am facing is that when -drawCircle: inContext: is called I get a long list of CGContext errors, starting with <Error>: CGContextSaveGState: invalid context and ending with CGBitmapContextCreateImage: invalid context I played around with making context the view's ivar and it worked so i am sure the context is the problem but I don't know what. I've tried CGContextFlush but it didn't help. Any help would be appreciated thank you

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  • How to create a CGBitmapContext which works for Retina display and not wasting space for regular display?

    - by ????
    Is it true that if it is in UIKit, including drawRect, the HD aspect of Retina display is automatically handled? So does that mean in drawRect, the current graphics context for a 1024 x 768 view is actually a 2048 x 1536 pixel Bitmap context? (is there a way to print this size out to verify it). We actually enjoy the luxury of 1 point = 4 pixels automatically handled for us. However, if we use CGBitmapContextCreate, then those will really be pixels, not points? (at least if we provide a data buffer for that bitmap, the size is not for the higher resolution, but for the standard resolution, and even if we pass NULL as the buffer so that CGBitmapContextCreate handles the buffer for us, the size probably is the same as if we pass in a data buffer, and it is just standard resolution, not Retina's resolution). We can always create 2048 x 1536 for iPad 1 and iPad 2 as well as the New iPad, but it will waste memory and processor and GPU power, as it is only needed for the New iPad. So do we have to use a if () { } else { } to create such a bitmap context and how do we actually do so? And all our code CGContextMoveToPoint has to be adjusted for Retina display to use x * 2 and y * 2 vs non-retina display of just using x, y as well? That can be quite messy for the code. (or maybe we can define a local variable scaleFactor and set it to 1 for standard resolution and 2 if it is retina, so our x and y will always be x * scaleFactor, y * scaleFactor instead of just x and y.) It seems that UIGraphicsBeginImageContextWithOptions can create one for Retina automatically if the scale of 0.0 is passed in, but I don't think it can be used if I need to create the context and keep it (and using ivar or property of UIViewController to hold it). If I don't release it using UIGraphicsEndImageContext, then it stays in the graphics context stack, so it seems like I have to use CGBitmapContextCreate instead. (or do we just let it stay at the bottom of the stack and not worry about it?)

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  • Why is there no autorelease pool when I do performSelectorInBackground: ?

    - by Thanks
    I am calling a method that goes in a background thread: [self performSelectorInBackground:@selector(loadViewControllerWithIndex:) withObject:[NSNumber numberWithInt:viewControllerIndex]]; then, I have this method implementation that gets called by the selector: - (void) loadViewControllerWithIndex:(NSNumber *)indexNumberObj { NSAutoreleasePool *arPool = [[NSAutoreleasePool alloc] init]; NSInteger vcIndex = [indexNumberObj intValue]; Class c; UIViewController *controller = [viewControllers objectAtIndex:vcIndex]; switch (vcIndex) { case 0: c = [MyFirstViewController class]; break; case 1: c = [MySecondViewController class]; break; default: NSLog(@"unknown index for loading view controller: %d", vcIndex); // error break; } if ((NSNull *)controller == [NSNull null]) { controller = [[c alloc] initWithNib]; [viewControllers replaceObjectAtIndex:vcIndex withObject:controller]; [controller release]; } if (controller.view.superview == nil) { UIView *placeholderView = [viewControllerPlaceholderViews objectAtIndex:vcIndex]; [placeholderView addSubview:controller.view]; } [arPool release]; } Althoug I do create an autorelease pool there for that thread, I always get this error: 2009-05-30 12:03:09.910 Demo[1827:3f03] *** _NSAutoreleaseNoPool(): Object 0x523e50 of class NSCFNumber autoreleased with no pool in place - just leaking Stack: (0x95c83f0f 0x95b90442 0x28d3 0x2d42 0x95b96e0d 0x95b969b4 0x93a00155 0x93a00012) If I take away the autorelease pool, I get a whole bunch of messages like these. I also tried to create an autorelease pool around the call of the performSelectorInBackground:, but that doesn't help. I suspect the parameter, but I don't know why the compiler complains about an NSCFNumber. Am I missing something? My Instance variables are all "nonatomic". Can that be a problem? UPDATE: I may also suspect that some variable has been added to an autorelease pool of the main thread (maybe an ivar), and now it trys to release that one inside the wrong autorelease pool? If so, how could I fix that? (damn, this threading stuff is complex ;) )

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  • UIViewController memory management

    - by jAmi
    Hi I have a very basic issue of memory management with my UIViewController (or any other object that I create); The problem is that in Instruments my Object allocation graph is always rising even though I am calling release on then assigning them nil. I have 2 UIViewController sub-classes each initializing with a NIB; I add the first ViewController to the main window like [window addSubView:first.view]; Then in my first ViewController nib file I have a Button which loads the second ViewController like : -(IBAction)loadSecondView{ if(second!=nil){ //second is set as an iVar and @property (nonatomic, retain)ViewController2* sceond; [second release]; second=nil; } second=[[ViewController2* second]initWithNibName:@"ViewController2" bundle:nil]; [self.view addSubView:second.view]; } In my (second) ViewController2 i have a button with an action method -(IBAction) removeSecond{ [self.view removeFromSuperView]; } Please let me know if the above scheme works in a managed way for memory...? In Instruments It does not show release of any allocation and keeps the bar status graph keeps on rising.

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  • Added CAGradientLayer, getting this in my UIView dealloc: [CALayer release]: message sent to deallocated instance

    - by developerdoug
    Here there, I have a custom UIView. This view acts as a activity indicator but as label above the UIActivityIndicatorView. In the init, I add a CAGradientLayer. I allocate and initialize it and insert it at index 0 as a sublayer of the UIView layer property. In my dealloc method was called, I received a message in the console: - [CALayer release]: message sent to deallocated instance. My code: @interface LabelActivityIndicatorView () { UILabel *_label; UIActivityIndicatorView *_activityIndicatorView; CAGradientLayer *_gradientLayer; } @end @implementation LabelActivityIndicatorView //dealloc - (void) dealloc { [_label release]; [_activityIndicatorView release]; //even tried to remove the layer [_gradientLayer removeFromSuperLayer]; [_gradientLayer release]; [super dealloc]; } // init - (id) initWithFrame:(CGRect)frame { if ( (self = [super initWithFrame:frame]) ) { // init the label // init the gradient layer _gradientLayer = [[CAGradientLayer alloc] init]; [_gradientLayer setBounds:[self bounds]]; [_gradientLayer setPosition:CGPointMake(frame.size.width/2, frame.size.height/2)]; [[self layer] insertSublayer:_gradientLayer atIndex:0]; [[self layer] setNeedsDisplay]; } return self; } @end Anyone have any ideas. Since I'm allocating and initializing the gradient layer I'm responsible for releasing it. I should be able to alloc and init and assign to some ivar. Perhaps I should create a property with retain on it. Thanks,

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  • How to hadle a tags inside another tags in NSXMLParser

    - by SimpleMan
    I have a file: <xml> <component>something <system>somethingDeeper <value>somethingDeepest</value> </system> </component> <component>somethinfDifferent <value>somethingDifferentDeeper</value> </component> <value>somethingNew</value> </xml> So i want to distinguish what is inside another tag (ex. <system>) what is not. How to do this with NSXMLParser ? I currently use BOOL ivar's but this is a lot of tags and this is not as elegant as i want it to be. I know that NSXMLParser is a SAX parser and i understand that. In above example I will be enter to didEndElement method three times with: elementName equal value Is there a more elegant way to distinguish what entry was from <component> tag above what not?

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  • objective C underscore property vs self

    - by user1216838
    I'm was playing around with the standard sample split view that gets created when you select a split view application in Xcode, and after adding a few fields i needed to add a few fields to display them in the detail view. and something interesting happend in the original sample, the master view sets a "detailItem" property in the detail view and the detail view displays it. - (void)setDetailItem:(id) newDetailItem { if (_detailItem != newDetailItem) { _detailItem = newDetailItem; // Update the view. [self configureView]; } i understand what that does and all, so while i was playing around with it. i thought it would be the same if instead of _detailItem i used self.detailItem, since it's a property of the class. however, when i used self.detailItem != newDetailItem i actually got stuck in a loop where this method is constantly called and i cant do anything else in the simulator. my question is, whats the actual difference between the underscore variables(ivar?) and the properties? i read some posts here it seems to be just some objective C convention, but it actually made some difference.

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  • Deleting from 2 arrays of dictionaries

    - by Matt Winters
    I have an array of dictionaries loaded from a plist (below) called arrayHistory. <plist version="1.0"> <array> <dict> <key>item</key> <string>1</string> <key>result</key> <string>8.1</string> <key>date</key> <date>2009-12-15T19:36:59Z</date> </dict> ... </array> </plist> I filter this array based on 'item' so that a second array, arrayHistoryDetail has the same structure as arrayHistory but only contains e.g. 'item's equal to '1'. These detail items are successfully displayed in a tableView. I then want to select an item from the tableView, and delete it from the tableView data source, arrayHistoryDetail (line 2 in the code below) - works, then I want to delete the item from the tableView itself (line 3 in the code below) - also works. My problem is that I also need to delete it from the original arrayHistory, so I tried the following: created a temporary dictionary as an ivar: NSMutableDictionary *tempDict; @property (nonatomic, retain) NSMutableDictionary *tempDict; Then my thinking was to make a copy in line 1 and remove it from the original array in line 4. 1 tempDict = [arrayHistoryDetail objectAtIndex: indexPath.row]; 2 [arrayHistoryDetail removeObjectAtIndex: indexPath.row]; 3 [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade]; 4 [arrayHistory removeObject:tempDict]; Didn't work. Could someone please guide me in the right direction. I'm thinking that tempDict is a pointer and that removeObject needs a copy? I don't know. Thanks.

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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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  • iPhone: value of selectedIndex for tab should be consistent, but isn't

    - by Janine
    This should be so simple... but something screwy is happening. My setup looks like this: MainViewController Tab Bar Controller 4 tabs, each of which loads WebViewController My AppDelegate contains an ivar, tabBarController, which is connected to the tab bar controller (this was all set up in Interface Builder). The leftmost tab is marked "selected" in IB. Within the viewWillAppear method in WebViewController, I need to know which tab was just selected so I can load the correct URL. I do this by switching on appDelegate.tabBarController.selectedIndex. When the app first runs and the leftmost tab is selected, selectedIndex is a large garbage value. After that, I get values from 0 to 3, which is as it should be, but they are in random order. Not only that, but each tab I touch reports a different value each time. This app is extremely simple right now and I can't imagine what I could have done to make things go this wrong. Has anyone seen (and hopefully solved) this behavior? Update: we have a request for code. There's not much to see. The tab bar controller gets loaded in applicationDidFinishLaunching: [self.mainViewController view]; //force nib to load [self.window addSubview:self.mainViewController.tabBarController.view] There is currently no code whatsoever in MainViewController.m other than the synthesize and release for tabBarController. From WebVewController.m: - (void)viewWillAppear:(BOOL)_animation { [super viewWillAppear:_animation]; NSURL *url; switch([S_UIDelegate mainViewController].tabBarController.selectedIndex) { case 0: url = [NSURL URLWithString:@"http://www.cnn.com"]; break; case 1: url = [NSURL URLWithString:@"http://www.facebook.com"]; break; case 2: url = [NSURL URLWithString:@"http://www.twitter.com"]; break; case 3: url = [NSURL URLWithString:@"http://www.google.com"]; break; default: url = [NSURL URLWithString:@"http://www.msnbc.com"]; } NSURLRequest *request = [NSURLRequest requestWithURL:url]; [webView loadRequest:request]; } This is where I'm seeing the random values.

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  • iPhone OS: KVO: Why is my Observer only getting notified at applicationDidfinishLaunching

    - by nickthedude
    I am basically trying to implement an achievement tracking setup in my app. I have a managedObjectModel class called StatTracker to keep track of all sorts of stats and I want my Achievement tracking class to be notified when those stats change so I can check them against a value and see if the user has earned an achievement. I've tried to impliment KVO and I think I'm pretty close to making it happen but the problem I'm running into is this: So in the appDelegate i have an Ivar for my Achievement tracker class, I attach it as an observer to a property value of my statTracker core data entity in the applicationDidFinishLaunching method. I know its making the connection because I've been able to trigger a UIAlert in my AchievementTracker instance, and I've put several log statements that should be triggered whenever the value on the StatTracker's property changes. the log statement appears only once at the application launch. I'm wondering if I'm missing something in the whole object lifecycle scheme of things, I just don't understand why the observer stops getting notified of changes after the applicationDidFinishLaunching method has run. Does it have something to do with the scope of the AchievementTracker reference or more likely the reference to my core data StatTracker is going away once that method finishes up. I guess I'm not sure the right place to place these if that is the case. Would love some help. Here is the code where I add the observer in my appDidFinishLaunching method: [[CoreDataSingleton sharedCoreDataSingleton] incrementStatTrackerStat:@"timesLaunched"]; achievementsObserver = [[AchievementTracker alloc] init]; StatTracker *object = nil; object = [[[CoreDataSingleton sharedCoreDataSingleton] getStatTracker] objectAtIndex:0]; NSLog(@"%@",[object description]); [[CoreDataSingleton sharedCoreDataSingleton] addObserver:achievementsObserver toStat:@"refreshCount"]; here is the code in my core data singleton: -(void) addObserver:(id)observer toStat:(NSString *) statToObserve { NSLog(@"observer added"); NSArray *array = [[NSArray alloc] init]; array = [self getStatTracker]; [[array objectAtIndex:0] addObserver:observer forKeyPath:statToObserve options:NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld context:NULL]; } and my AchievementTracker: - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context { NSLog(@"achievemnt hit"); //NSLog("%@", [change description]); if ([keyPath isEqual:@"refreshCount"] && ((NSInteger)[change valueForKey:@"NSKeyValueObservingOptionOld"] == 60) ) { NSLog(@"achievemnt hit inside"); UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"title" message:@"achievement unlocked" delegate:self cancelButtonTitle:@"cancel" otherButtonTitles:nil]; [alert show]; } }

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  • OpenGL ES functions not accepting values originating outside of it's view

    - by Josh Elsasser
    I've been unable to figure this out on my own. I currently have an Open GLES setup where a view controller both updates a game world (with a dt), fetches the data I need to render, passes it off to an EAGLView through two structures (built of Apple's ES1Renderer), and draws the scene. Whenever a value originates outside of the Open GL view, it can't be used to either translate objects using glTranslatef, or set up the scene using glOrthof. If I assign a new value to something, it will work - even if it is the exact same number. The two structures I have each contain a variety of floating-point numbers and booleans, along with two arrays. I can log the values from within my renderer - they make it there - but I receive errors from OpenGL if I try to do anything with them. No crashes result, but the glOrthof call doesn't work if I don't set the camera values to anything different. Code used to set up scene: [EAGLContext setCurrentContext:context]; glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer); //clears the color buffer bit glClear(GL_COLOR_BUFFER_BIT); glMatrixMode(GL_PROJECTION); //sets up the scene w/ ortho projection glViewport(0, 0, 320, 480); glLoadIdentity(); glOrthof(320, 0, dynamicData.cam_x2, dynamicData.cam_x1, 1.0, -1.0); glClearColor(1.0, 1.0, 1.0, 1.0); /*error checking code here*/ "dynamicData" (which is replaced every frame) is created within my game simulation. From within my controller, I call a method (w/in my simulation) that returns it, and pass the result on to the EAGLView, which passes it on to the renderer. I haven't been able to come up with a better solution for this - suggestions in this regard would be greatly appreciated as well. Also, this function doesn't work as well (values originate in the same place): glTranslatef(dynamicData.ship_x, dynamicData.ship_y, 0.0); Thanks in advance. Additional Definitions: Structure (declared in a separate header): typedef struct { float ship_x, ship_y; float cam_x1, cam_x2; } dynamicRenderData; Render data getter (and builder) (every frame) - (dynamicData)getDynRenderData { //d_rd is an ivar, zeroed on initialization d_rd.ship_x = mainShip.position.x; d_rd.ship_y = mainShip.position.y; d_rd.cam_x1 = d_rd.ship_x - 30.0f; d_rd.cam_x2 = d_rd.cam_x1 + 480.0f; return d_rd; } Zeroed at start. (d_rd.ship_x = 0;, etc…) Setting up the view. Prototype (GLView): - (void)draw: (dynamicRenderData)dynamicData Prototype (Renderer): - (void)drawView: (dynamicRenderData)dynamicData How it's called w/in the controller: //controller [glview draw: [world getDynRenderData]]; //glview (within draw) [renderer drawView: dynamicData];

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  • Restrict sprite movement to vertical and horizontal

    - by Daniel Granger
    I have been battling with this for some time and my noob brain can't quite work it out. I have a standard tile map and currently use the following code to move my enemy sprite around the map -(void) movePlayer:(ccTime)deltaTime { if (CGPointEqualToPoint(self.position, requestedPosition)) return; float step = kPlayerSpeed * deltaTime; float dist = ccpDistance(self.position, requestedPosition); CGPoint vectorBetweenAB = ccpSub(self.position, requestedPosition); if (dist <= step) { self.position = requestedPosition; [self popPosition]; } else { CGPoint normVectorBetweenAB = ccpNormalize(vectorBetweenAB); CGPoint movementVectorForThisFrame = ccpMult(normVectorBetweenAB, step); if (abs(vectorBetweenAB.x) > abs(vectorBetweenAB.y)) { if (vectorBetweenAB.x > 0) { [self runAnimation:walkLeft]; } else { [self runAnimation:walkRight]; } } else { if (vectorBetweenAB.y > 0) { [self runAnimation:walkDown]; } else { [self runAnimation:walkUp]; } } if (self.position.x > movementVectorForThisFrame.x) { movementVectorForThisFrame.x = -movementVectorForThisFrame.x; } if (self.position.y > movementVectorForThisFrame.y) { movementVectorForThisFrame.y = -movementVectorForThisFrame.y; } self.position = ccpAdd(self.position, movementVectorForThisFrame); } } movePlayer: is called by the classes updateWithDeltaTime: method. the ivar requestedPosition is set in the updateWithDeltaTime method as well, it basically gets the next point out of a queue to move to. These points can be anywhere on the map, so if they are in a diagonal direction from the enemy the enemy sprite will move directly to that point. But how do I change the above code to restrict the movement to vertical and horizontal movement only so that the enemies movement 'staircases' its way along a diagonal path, taking the manhattan distance (I think its called). As shown by my crude drawing below... S being the start point F being the finish and the numbers being each intermediate point along its path to create a staircase type diagonal movement. Finally I intend to be able to toggle this behaviour on and off, so that I can choose whether or not I want the enemy to move free around the map or be restricted to this horizontal / vertical movement only. | | | | | | | | | | | | | | | | | | | | | |F| | | | | | | | | |5|4| | | | | | | | | |3|2| | | | | | | | | |1|S| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

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  • Marking multi-level nested forms as "dirty" in Rails

    - by Charles Kihe
    I have a three-level multi-nested form in Rails. The setup is like this: Projects have many Milestones, and Milestones have many Notes. The goal is to have everything editable within the page with JavaScript, where we can add multiple new Milestones to a Project within the page, and add new Notes to new and existing Milestones. Everything works as expected, except that when I add new notes to an existing Milestone (new Milestones work fine when adding notes to them), the new notes won't save unless I edit any of the fields that actually belong to the Milestone to mark the form "dirty"/edited. Is there a way to flag the Milestone so that the new Notes that have been added will save? Edit: sorry, it's hard to paste in all of the code because there's so many parts, but here goes: Models class Project < ActiveRecord::Base has_many :notes, :dependent => :destroy has_many :milestones, :dependent => :destroy accepts_nested_attributes_for :milestones, :allow_destroy => true accepts_nested_attributes_for :notes, :allow_destroy => true, :reject_if => proc { |attributes| attributes['content'].blank? } end class Milestone < ActiveRecord::Base belongs_to :project has_many :notes, :dependent => :destroy accepts_nested_attributes_for :notes, :allow_destroy => true, :allow_destroy => true, :reject_if => proc { |attributes| attributes['content'].blank? } end class Note < ActiveRecord::Base belongs_to :milestone belongs_to :project scope :newest, lambda { |*args| order('created_at DESC').limit(*args.first || 3) } end I'm using an jQuery-based, unobtrusive version of Ryan Bates' combo helper/JS code to get this done. Application Helper def add_fields_for_association(f, association, partial) new_object = f.object.class.reflect_on_association(association).klass.new fields = f.fields_for(association, new_object, :child_index => "new_#{association}") do |builder| render(partial, :f => builder) end end I render the form for the association in a hidden div, and then use the following JavaScript to find it and add it as needed. JavaScript function addFields(link, association, content, func) { var newID = new Date().getTime(); var regexp = new RegExp("new_" + association, "g"); var form = content.replace(regexp, newID); var link = $(link).parent().next().before(form).prev(); if (func) { func.call(); } return link; } I'm guessing the only other relevant piece of code that I can think of would be the create method in the NotesController: def create respond_with(@note = @owner.notes.create(params[:note])) do |format| format.js { render :json => @owner.notes.newest(3).all.to_json } format.html { redirect_to((@milestone ? [@project, @milestone, @note] : [@project, @note]), :notice => 'Note was successfully created.') } end end The @owner ivar is created in the following before filter: def load_milestone @milestone = @project.milestones.find(params[:milestone_id]) if params[:milestone_id] end def determine_owner @owner = load_milestone @owner ||= @project end Thing is, all this seems to work fine, except when I'm adding new notes to existing milestones. The milestone has to be "touched" in order for new notes to save, or else Rails won't pay attention.

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  • How to implement Cocoa copyWithZone on derived object in MonoMac C#?

    - by Justin Aquadro
    I'm currently porting a small Winforms-based .NET application to use a native Mac front-end with MonoMac. The application has a TreeControl with icons and text, which does not exist out of the box in Cocoa. So far, I've ported almost all of the ImageAndTextCell code in Apple's DragNDrop example: https://developer.apple.com/library/mac/#samplecode/DragNDropOutlineView/Listings/ImageAndTextCell_m.html#//apple_ref/doc/uid/DTS40008831-ImageAndTextCell_m-DontLinkElementID_6, which is assigned to an NSOutlineView as a custom cell. It seems to be working almost perfectly, except that I have not figured out how to properly port the copyWithZone method. Unfortunately, this means the internal copies that NSOutlineView is making do not have the image field, and it leads to the images briefly vanishing during expand and collapse operations. The objective-c code in question is: - (id)copyWithZone:(NSZone *)zone { ImageAndTextCell *cell = (ImageAndTextCell *)[super copyWithZone:zone]; // The image ivar will be directly copied; we need to retain or copy it. cell->image = [image retain]; return cell; } The first line is what's tripping me up, as MonoMac does not expose a copyWithZone method, and I don't know how to otherwise call it. Update Based on current answers and additional research and testing, I've come up with a variety of models for copying an object. static List<ImageAndTextCell> _refPool = new List<ImageAndTextCell>(); // Method 1 static IntPtr selRetain = Selector.GetHandle ("retain"); [Export("copyWithZone:")] public virtual NSObject CopyWithZone(IntPtr zone) { ImageAndTextCell cell = new ImageAndTextCell() { Title = Title, Image = Image, }; Messaging.void_objc_msgSend (cell.Handle, selRetain); return cell; } // Method 2 [Export("copyWithZone:")] public virtual NSObject CopyWithZone(IntPtr zone) { ImageAndTextCell cell = new ImageAndTextCell() { Title = Title, Image = Image, }; _refPool.Add(cell); return cell; } [Export("dealloc")] public void Dealloc () { _refPool.Remove(this); this.Dispose(); } // Method 3 static IntPtr selRetain = Selector.GetHandle ("retain"); [Export("copyWithZone:")] public virtual NSObject CopyWithZone(IntPtr zone) { ImageAndTextCell cell = new ImageAndTextCell() { Title = Title, Image = Image, }; _refPool.Add(cell); Messaging.void_objc_msgSend (cell.Handle, selRetain); return cell; } // Method 4 static IntPtr selRetain = Selector.GetHandle ("retain"); static IntPtr selRetainCount = Selector.GetHandle("retainCount"); [Export("copyWithZone:")] public virtual NSObject CopyWithZone (IntPtr zone) { ImageAndTextCell cell = new ImageAndTextCell () { Title = Title, Image = Image, }; _refPool.Add (cell); Messaging.void_objc_msgSend (cell.Handle, selRetain); return cell; } public void PeriodicCleanup () { List<ImageAndTextCell> markedForDelete = new List<ImageAndTextCell> (); foreach (ImageAndTextCell cell in _refPool) { uint count = Messaging.UInt32_objc_msgSend (cell.Handle, selRetainCount); if (count == 1) markedForDelete.Add (cell); } foreach (ImageAndTextCell cell in markedForDelete) { _refPool.Remove (cell); cell.Dispose (); } } // Method 5 static IntPtr selCopyWithZone = Selector.GetHandle("copyWithZone:"); [Export("copyWithZone:")] public virtual NSObject CopyWithZone(IntPtr zone) { IntPtr copyHandle = Messaging.IntPtr_objc_msgSendSuper_IntPtr(SuperHandle, selCopyWithZone, zone); ImageAndTextCell cell = new ImageAndTextCell(copyHandle) { Image = Image, }; _refPool.Add(cell); return cell; } Method 1: Increases the retain count of the unmanaged object. The unmanaged object will persist persist forever (I think? dealloc never called), and the managed object will be harvested early. Seems to be lose-lose all-around, but runs in practice. Method 2: Saves a reference of the managed object. The unmanaged object is left alone, and dealloc appears to be invoked at a reasonable time by the caller. At this point the managed object is released and disposed. This seems reasonable, but on the downside the base type's dealloc won't be run (I think?) Method 3: Increases the retain count and saves a reference. Unmanaged and managed objects leak forever. Method 4: Extends Method 3 by adding a cleanup function that is run periodically (e.g. during Init of each new ImageAndTextCell object). The cleanup function checks the retain counts of the stored objects. A retain count of 1 means the caller has released it, so we should as well. Should eliminate leaking in theory. Method 5: Attempt to invoke the copyWithZone method on the base type, and then construct a new ImageAndTextView object with the resulting handle. Seems to do the right thing (the base data is cloned). Internally, NSObject bumps the retain count on objects constructed like this, so we also use the PeriodicCleanup function to release these objects when they're no longer used. Based on the above, I believe Method 5 is the best approach since it should be the only one that results in a truly correct copy of the base type data, but I don't know if the approach is inherently dangerous (I am also making some assumptions about the underlying implementation of NSObject). So far nothing bad has happened "yet", but if anyone is able to vet my analysis then I would be more confident going forward.

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