animation in xcode

Question

when I doing animation with the next code:

NSArray *images=[NSArray arrayWithObjects:[UIImage imageNamed:@"shavit_1.png"],[UIImage imageNamed:@"shavit_1.png"],[UIImage imageNamed:@"shavit_2.png"],[UIImage imageNamed:@"shavit_3.png"],[UIImage imageNamed:@"shavit_4.png"],[UIImage imageNamed:@"shavit_5.png"],[UIImage imageNamed:@"shavit_6.png"],[UIImage imageNamed:@"shavit_7.png"],[UIImage imageNamed:@"shavit_8.png"],[UIImage imageNamed:@"shavit_9.png"],[UIImage imageNamed:@"shavit_10.png"],[UIImage imageNamed:@"shavit_11.png"],[UIImage imageNamed:@"shavit_12.png"],[UIImage imageNamed:@"shavit_13.png"],[UIImage imageNamed:@"shavit_14.png"],[UIImage imageNamed:@"shavit_15.png"],[UIImage imageNamed:@"shavit_16.png"],[UIImage imageNamed:@"shavit_17.png"],[UIImage imageNamed:@"shavit_18.png"],[UIImage imageNamed:@"shavit_19.png"],[UIImage imageNamed:@"shavit_20.png"],[UIImage imageNamed:@"shavit_21.png"],[UIImage imageNamed:@"shavit_22.png"],[UIImage imageNamed:@"shavit_23.png"],[UIImage imageNamed:@"shavit_24.png"],[UIImage imageNamed:@"shavit_25.png"],nil];


    shavitimage.animationImages=images;
    shavitimage.animationDuration=2.0;
    shavitimage.animationRepeatCount=1;
    [shavitimage startAnimating];

    [images release]; //release the used array 

    [self performSelector:@selector(animation_ends) withObject:nil afterDelay:2.0];//after 2 seconds put astatic image

    timer=[NSTimer scheduledTimerWithTimeInterval:10.0 target:self selector:@selector(timerFireMethod:) userInfo:nil repeats:NO];
}

-(void)animation_ends{
    [shavitimage stopAnimating];//the UIImageView return to static mode
    shavitimage.image=[UIImage imageNamed:@"shavit_25.png"];
    self.view.userInteractionEnabled=YES;
}

the animation is working well,and the application working well after the end of the animation. but when I doing animation with the next code:

NSMutableArray *images=[NSMutableArray array]; //insrt the images dynamiclly
for(int i=1;i<=25;i++)
{
 NSString *file=@"shavit_"; 
 file=[file stringByAppendingFormat:@"%d",i];
 NSString *filePath = [[NSBundle mainBundle] pathForResource:file ofType:@"png"];
 [images addObject:[UIImage imageWithContentsOfFile:filePath]];
 [file release];    
 [filePath release];    
}   


shavitimage.animationImages=images;
shavitimage.animationDuration=2.0;
shavitimage.animationRepeatCount=1;
[shavitimage startAnimating];

[images release]; //release the used array 

[self performSelector:@selector(animation_ends) withObject:nil afterDelay:2.0];//after 2 seconds put astatic image

timer=[NSTimer scheduledTimerWithTimeInterval:10.0 target:self selector:@selector(timerFireMethod:) userInfo:nil repeats:NO];
}

-(void)animation_ends{
    [shavitimage stopAnimating];//the UIImageView return to static mode
    shavitimage.image=[UIImage imageNamed:@"shavit_25.png"];
    self.view.userInteractionEnabled=YES;
}

the animation is working well,but it stack after.why does it happen?

Answer 1

@synthesize myImage;

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    NSMutableArray *a = [NSMutableArray array];
    //[a addObject: [UIViewController ]];
    [a addObject:[UIImage imageNamed:@"1.gif"]];
    [a addObject:[UIImage imageNamed:@"2.gif"]];
    [a addObject:[UIImage imageNamed:@"3.gif"]];
    [a addObject:[UIImage imageNamed:@"4.gif"]];
    [a addObject:[UIImage imageNamed:@"5.gif"]];
    [a addObject:[UIImage imageNamed:@"6.gif"]];
    [a addObject:[UIImage imageNamed:@"7.gif"]];

    //[myImage initWithFrame:CGRectMake(0, 0, 131, 125)];

    myImage.animationImages = a;
    myImage.animationDuration=5;
    myImage.animationRepeatCount=0;
    myImage.startAnimating;
    [self.view addSubview:myImage];
}

Answer 2

Do not release an autoreleased object.

That's the gist of it.

Evaluation of chain of events :–

1. You create an autoreleased array. Retain Count = 1 (will diminish by 1 in near future)
2. UIImageView object retains the array when you set animationImages. Retain Count = 2
3. You release the array. Retain Count = 1
4. Autorelease kicks in. Retain Count = 0 (object is deallocated)

Now the UIImageView still thinks that it has ownership of the array. When it tries to access it then it should result in an error. If it isn't animating and then is later deallocated, it will try to send a release message to the deallocated instance which should also crash the application. All of this is fair assumption as we don't know if the framework is adding its own memory management calls in any way.

Now both the pieces of code have the same problem and are both unreliable.

Be a good memory citizen and remove the release call.