Question

I will like to know how to release the memory from the animating array, somehow in instruments the animating picture are eating up 24MB of real memory. what should i do to release the memory ? the total picture file size are about 3MB in Mac OS.

*EDIT:*Cool, i enabled the ARC setting in the build setting, no longer crashing…but memory usages still hovering around 80 – 120mb physical memory…..

this is the line that run for the image.

    -(void)defaultSetup
{

    self.imageArray = [[NSMutableArray alloc] initWithObjects:
                       [UIImage imageWithContentsOfFile:[[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"default/d7.jpg"]],
                        [UIImage imageWithContentsOfFile:[[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"default/d9.jpg"]],
                        [UIImage imageWithContentsOfFile:[[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"default/d11.jpg"]],
                        [UIImage imageWithContentsOfFile:[[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"default/d27.jpg"]],
                        [UIImage imageWithContentsOfFile:[[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"default/d6.jpg"]],                        
                        nil];
    self.defaultID = [[NSMutableArray alloc] initWithObjects:@"0",@"1",@"2",@"3",@"0",nil];
    self.defaultImageCaption = [[NSMutableArray alloc] initWithObjects:@"Ver",@"Green",@"Red",@"Cru",@"East",nil];      


    NSUInteger count = [self.defaultID count];
    NSLog(@"Count %i",[self.defaultID count]);
    NSMutableArray *randomImgName = self.imageArray;
    NSMutableArray *randomID = self.defaultID;
    NSMutableArray *randomName = self.defaultImageCaption;

    for (NSUInteger i = 0; i < count; ++i) {
        // Select a random element between i and end of array to swap with.
        int nElements = count - i;
        int n = (arc4random() % nElements) + i;
        [randomName exchangeObjectAtIndex:i withObjectAtIndex:n];
        [randomImgName exchangeObjectAtIndex:i withObjectAtIndex:n];
        [randomID exchangeObjectAtIndex:i withObjectAtIndex:n];
    }
    self.imageArray = randomImgName;
    self.defaultID=randomID;
    self.defaultImageCaption=randomName;

    NSLog(@"default filename %@",self.defaultImageCaption);
    NSLog(@"default ID %@",self.defaultID);
    self.imageViewTop.alpha = 1.0;
    self.imageViewBottom.alpha = 0.0;
    self.imageViewBottom = [[[UIImageView alloc] initWithFrame:CGRectMake(0,44,320,367)] autorelease];
    self.imageViewTop = [[[UIImageView alloc] initWithFrame:CGRectMake(0,44,320,367)] autorelease];
    [self.view addSubview:imageViewTop];
    [self.view addSubview:imageViewBottom];

    self.buttonCaption = [UIButton buttonWithType:UIButtonTypeCustom];
    //default placement
    self.buttonCaption.frame = CGRectMake(245, 365, 70, 30);
    //[buttonCaption setTitle:@"\u00A9"  forState:UIControlStateNormal];
    [self.buttonCaption addTarget:self action:@selector(buttonCheck) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:self.buttonCaption];

    [self nextAnimation:buttonCaption.frame.size.width]; 

}

-(void)nextAnimation:(float)previousWidth {

    //picture loop
    imageViewTop.image = imageViewBottom.image;
    imageViewBottom.image = [imageArray objectAtIndex:[imageArray count] - 1];

    [imageArray insertObject:imageViewBottom.image atIndex:0];
    [imageArray removeLastObject];
    imageViewTop.alpha = 1.0;
    imageViewBottom.alpha = 0.0;

    //Name Caption
    NSString * tempCaption = [defaultImageCaption objectAtIndex:[defaultImageCaption count]-1];
    self.dID = [defaultID objectAtIndex:[defaultID count]-1];

    // make the buttons content appear in the top-left
    [buttonCaption setContentHorizontalAlignment:UIControlContentHorizontalAlignmentCenter];
    [buttonCaption setContentVerticalAlignment: UIControlContentVerticalAlignmentCenter ];



    [defaultImageCaption insertObject:tempCaption atIndex:0];
    [defaultImageCaption removeLastObject];
    [defaultID insertObject:dID atIndex:0];
    [defaultID removeLastObject];

    [UIView animateWithDuration:1 delay:2 options:0       
                     animations:^{                          
                         [buttonCaption setTitle:tempCaption  forState:UIControlStateNormal];
                         //NSLog(@"Name %@",tempCaption );
                         //NSLog(@"ID %@",dID);
                     } 
                     completion:^(BOOL  completed)
     {
     }];  

Answer 1

Read up on Cocoa memory management. (I’m assuming you’re not using ARC (automatic reference counting).) Btw, I’d consider using ARC, it makes your life easier. (It’s a compile-time technology, so is backwards compatible with older iOS runtimes, but you don’t get weak reference support on older iOS runtimes.)

To summarise the memory management rules: everything that increases your retain count on an object should be balanced by something that decreases the retain count at some point.

Things that increment the retain count:

self.propertyName = anInstance, when that property is declared with retain property.

[objectInstance retain].

[Class alloc], [Class new], [objectInstance copy] or variants beginning with copy.

Adding an object to a standard collection class (e.g. NSArray).

Things that decrement the retain count:

self.propertyName = <some other object instance or nil>, when that property is declared with retain property.

[objectInstance release]

[objectInstance autorelease] (causes a release at some later time).

Removing an object from a standard collection class (e.g. NSArray).