My modal keeps eating memory - ios

Question

I am experiencing a rather serious issue with my iPhone app using ARC.
I have a viewcontroller (lets call this A). This viewcontroller opens a navigationcontroller as a modal which runs through 3 different viewcontrollers (lets call these 1, 2 and 3). After viewing number 3 the navigationcontroller closes and we're back to A again.
So the flow is: A opens navigationcontroller and goes through 1->2->3 and then it closes again.
Every time I go through this flow i lose memory. I've searched through all my files looking for any retain og strong properties, un-invalidated timers or similar in order to solve this problem.
I have one idea, which might be the problem. At viewcontroller 1 i present a animation using coreanimation and a sprite. I'm using a implementation made by someone else. It seems like if i disable the animations the memory used seems quite constant (and thereby no memory loss). I have modified the implementation a bit to use ARC. This is the implementation I use for my sprite animations:
MCSpriteLayer.h
//
// MCSpriteLayer.h
//
// Created by Miguel Angel Friginal on 8/20/10.
// Copyright 2010 Mystery Coconut Games. All rights reserved.
//
#import <Foundation/Foundation.h>
#import <QuartzCore/QuartzCore.h>
#interface MCSpriteLayer : CALayer {
unsigned int sampleIndex;
}
// SampleIndex needs to be > 0
#property (nonatomic) unsigned int sampleIndex;
// For use with sample rects set by the delegate
+ (id)layerWithImage:(CGImageRef)img;
- (id)initWithImage:(CGImageRef)img;
// If all samples are the same size
+ (id)layerWithImage:(CGImageRef)img sampleSize:(CGSize)size :(int)useRetina;
- (id)initWithImage:(CGImageRef)img sampleSize:(CGSize)size;
// Use this method instead of sprite.sampleIndex to obtain the index currently displayed on screen
- (unsigned int)currentSampleIndex;
#end
MCSpriteLayer.m
//
// MCSpriteLayer.m
//
// Created by Miguel Angel Friginal on 8/20/10.
// Copyright 2010 Mystery Coconut Games. All rights reserved.
//
#import "MCSpriteLayer.h"
#implementation MCSpriteLayer
#synthesize sampleIndex;
#pragma mark -
#pragma mark Initialization, variable sample size
- (id)initWithImage:(CGImageRef)img;
{
self = [super init];
if (self != nil)
{
self.contents = (__bridge id)img;
sampleIndex = 1;
}
return self;
}
+ (id)layerWithImage:(CGImageRef)img;
{
MCSpriteLayer *layer = [(MCSpriteLayer*)[self alloc] initWithImage:img];
return layer;
}
#pragma mark -
#pragma mark Initialization, fixed sample size
- (id)initWithImage:(CGImageRef)img sampleSize:(CGSize)size;
{
self = [self initWithImage:img];
if (self != nil)
{
CGSize sampleSizeNormalized = CGSizeMake(size.width/CGImageGetWidth(img), size.height/CGImageGetHeight(img));
self.bounds = CGRectMake( 0, 0, size.width, size.height );
self.contentsRect = CGRectMake( 0, 0, sampleSizeNormalized.width, sampleSizeNormalized.height );
}
return self;
}
+ (id)layerWithImage:(CGImageRef)img sampleSize:(CGSize)size :(int)useRetina;
{
CGSize newSampleSize;
if(useRetina == 1) {
// Supporting retina displays
if ([[UIScreen mainScreen] respondsToSelector:#selector(displayLinkWithTarget:selector:)] &&
([UIScreen mainScreen].scale == 2.0)) {
newSampleSize = CGSizeMake(size.width*2, size.height*2);
} else {
newSampleSize = size;
}
} else
newSampleSize = size;
MCSpriteLayer *layer = [[self alloc] initWithImage:img sampleSize:newSampleSize];
return layer;
}
#pragma mark -
#pragma mark Frame by frame animation
+ (BOOL)needsDisplayForKey:(NSString *)key;
{
return [key isEqualToString:#"sampleIndex"];
}
// contentsRect or bounds changes are not animated
+ (id < CAAction >)defaultActionForKey:(NSString *)aKey;
{
if ([aKey isEqualToString:#"contentsRect"] || [aKey isEqualToString:#"bounds"])
return (id < CAAction >)[NSNull null];
return [super defaultActionForKey:aKey];
}
- (unsigned int)currentSampleIndex;
{
return ((MCSpriteLayer*)[self presentationLayer]).sampleIndex;
}
// Implement displayLayer: on the delegate to override how sample rectangles are calculated; remember to use currentSampleIndex, ignore sampleIndex == 0, and set the layer's bounds
- (void)display;
{
if ([self.delegate respondsToSelector:#selector(displayLayer:)])
{
[self.delegate displayLayer:self];
return;
}
unsigned int currentSampleIndex = [self currentSampleIndex];
if (!currentSampleIndex)
return;
CGSize sampleSize = self.contentsRect.size;
self.contentsRect = CGRectMake(
((currentSampleIndex - 1) % (int)(1/sampleSize.width)) * sampleSize.width,
((currentSampleIndex - 1) / (int)(1/sampleSize.width)) * sampleSize.height,
sampleSize.width, sampleSize.height
);
}
#end
Is this implementation somehow not realeasing correctly or retaining anything? Thanks in advance.
Update
- I am using Instruments to measure the memory. I am using the Memory Monitor where I keep an eye on the Physical Memory Free
- The image is created like this:
NSString *path = [[NSBundle mainBundle] pathForResource:#"round_start.png" ofType:nil];
CGSize fixedSize = CGSizeMake(320, 480);
mascot = [MCSpriteLayer layerWithImage:[UIImage imageWithContentsOfFile:path].CGImage sampleSize:fixedSize :0];
mascot.frame = CGRectMake(ANIMATION_X, ANIMATION_Y, ANIMATION_WIDTH, ANIMATION_HEIGHT);
[self.view.layer addSublayer:mascot2];
CABasicAnimation *anim = [CABasicAnimation animationWithKeyPath:#"sampleIndex"];
anim.delegate = self;
anim.fromValue = [NSNumber numberWithInt:1];
anim.toValue = [NSNumber numberWithInt:52];
anim.duration = ANIMATION_DURATION;
anim.repeatCount = 1;
[mascot addAnimation:anim forKey:nil];
- I've been experiencing with closing the modal with
[self dismissModalViewControllerAnimated:YES];
and
[self.navigationController dismissModalViewControllerAnimated:YES];

Answer 1

Dismissing the navigation controller does not release it, assuming you have a strong reference to it (that would need to get nil'd). In the view controllers used by it, add a log message in the dealloc method, so you know they are getting dealloced (you can do this for any subclassed item). If needed you can create a simple UINavigation subclass for the sole purpose of adding a message in dealloc). You will find that one or more of these items are not getting dealloced, and then you need to figure out if they are retained by a property/ivar or because they still have a superview.