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POUIView and NSTimer not releasing memory
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  1. POUIView and NSTimer not releasing memory
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    copied!<p>I have a line of UILabel text in a UIView which is regularly updated via NSTimer. This code is supposed to write a status item near the bottom of the screen every so often. The data comes from outside of its control.</p> <p>My app runs out of memory really fast because it seems the UILabel is not being released. It seems that dealloc is never called.</p> <p>Here is a very compressed version of my code (error checking etc removed for clarity.):</p> <p>File:SbarLeakAppDelegate.h</p> <pre><code>#import &lt;UIKit/UIKit.h&gt; #import "Status.h" @interface SbarLeakAppDelegate : NSObject { UIWindow *window; Model *model; } @end </code></pre> <p>File:SbarLeakAppDelegate.m</p> <pre><code>#import "SbarLeakAppDelegate.h" @implementation SbarLeakAppDelegate - (void)applicationDidFinishLaunching:(UIApplication *)application { model=[Model sharedModel]; Status * st=[[Status alloc] initWithFrame:CGRectMake(0.0, 420.0, 320.0, 12.0)]; [window addSubview:st]; [st release]; [window makeKeyAndVisible]; } - (void)dealloc { [window release]; [super dealloc]; } @end </code></pre> <p>File:Status.h</p> <pre><code>#import &lt;UIKit/UIKit.h&gt; #import "Model.h" @interface Status : UIView { Model *model; UILabel * title; } @end </code></pre> <p>File:Status.m This is the where the problem lies. UILabel just does not seem to be released, and quite possible the string as well.</p> <pre><code>#import "Status.h" @implementation Status - (id)initWithFrame:(CGRect)frame { self=[super initWithFrame:frame]; model=[Model sharedModel]; [NSTimer scheduledTimerWithTimeInterval:.200 target:self selector:@selector(setNeedsDisplay) userInfo:nil repeats:YES]; return self; } - (void)drawRect:(CGRect)rect { title =[[UILabel alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, 12.0f)]; title.text = [NSString stringWithFormat:@"Tick %d", [model n]] ; [self addSubview:title]; [title release]; } - (void)dealloc { [super dealloc]; } @end </code></pre> <p>File: Model.h (this and the next are the data sources, so included only for completeness.) All it does is update a counter every second.</p> <pre><code>#import &lt;Foundation/Foundation.h&gt; @interface Model : NSObject { int n; } @property int n; +(Model *) sharedModel; -(void) inc; @end </code></pre> <p>File: Model.m</p> <pre><code>#import "Model.h" @implementation Model static Model * sharedModel = nil; + (Model *) sharedModel { if (sharedModel == nil) sharedModel = [[self alloc] init]; return sharedModel; } @synthesize n; -(id) init { self=[super init]; [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(inc) userInfo:nil repeats:YES]; return self; } -(void) inc { n++; } @end </code></pre>
 

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