uiview animatewithduration completion continues after view is dismissed - objective-c

Question

I have a modelViewController that contains a UIView animation. When the animation block finishes it calls itself, thus looping.
When I dismiss the modelViewController (dismissInfo) which calls [_starView removeFromSuperview], the function gets called over and over very rapidly with the NSLog line being printed multiple times a second.
#implementation InfoVC
{
NSArray *imgs;
NSString *currentImg;
}
- (void)viewDidLoad
{
[super viewDidLoad];
_imageview.contentMode = UIViewContentModeLeft;
_imageviewUnder.contentMode = UIViewContentModeLeft;
imgs = [NSArray arrayWithObjects:
#"01.jpg",
#"02.jpg",
#"03.jpg",
#"04.jpg",
#"05.jpg",
#"06.jpg",
nil];
_imgInt = (arc4random()%6);
[self initialImage];
}
- (void)viewWillAppear:(BOOL)animated{
}
- (void)viewDidAppear:(BOOL)animated{
NSLog(#"viewDidAppear");
}
- (void)initialImage
{
_starView.contentMode = UIViewContentModeLeft;
_imageviewUnder.contentMode = UIViewContentModeLeft;
currentImg = [imgs objectAtIndex:_imgInt];
UIImage *image = [UIImage imageNamed:currentImg];
_starView = [[UIImageView alloc] initWithImage:image];
// Size the image view to the image (it's bigger)
_starView.bounds = CGRectMake(0.0, 44.0, 416.0, 416.0);
NSLog(#"tarView.center %#", NSStringFromCGPoint(_starView.center) );
_starView.alpha=1;
int nextImgInt = _imgInt + 1 ;
if (nextImgInt>5)
{
nextImgInt=0;
}
NSString *nextImg = [imgs objectAtIndex:nextImgInt];
UIImage *nextImage = [UIImage imageNamed:nextImg];
[_imageviewUnder setImage:nextImage];
[self.view sendSubviewToBack:_imageviewUnder];
_imgInt++;
if (_imgInt>5) {
_imgInt=0;
}
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView animateWithDuration:7.6f
delay:0.1f
options:UIViewAnimationCurveLinear
animations:^{
[_starView setCenter:CGPointMake(112, 208)];
[_starView setAlpha:0.0f];
}
completion:^(BOOL finished){
[_starView removeFromSuperview];
[self initialImage];
}];
[self.view insertSubview:_starView atIndex:1];
}
- (void)visitTwitter
{
NSURL *URL = [NSURL URLWithString:#"http://twitter.com/"];
SVWebViewController *webViewController = [[SVWebViewController alloc] initWithURL:URL];
[self.navigationController pushViewController:webViewController animated:YES];
}
- (IBAction)dismissInfo:(id)sender
{
[self cleanup];
[self dismissModalViewControllerAnimated:YES];
}
- (void)cleanup
{
[_starView.layer removeAllAnimations];
[self.view.layer removeAllAnimations];
[_starView removeFromSuperview];
}
- (void)viewDidUnload
{
[self cleanup];
[super viewDidUnload];
}
#end

Answer 1

Make yourself an animating flag, set true in viewDidLoad, and false in cleanup. Then check it in your initialImage method:
if ( ! animating )
return;

Answer 2

This is the second time I've come across this. One possible cause is the method being initialised in viewDidLoad but the subview and image not being ready in time (it seems the first pass of the animation loop doesn't work adding a ghost to the machine).
I moved the call to ViewDidAppear, making sure to display an initialisation image to stop the white flash. At last an infinite animation in a modal window
- (void)viewDidLoad
{
[super viewDidLoad];
_imageview.contentMode = UIViewContentModeLeft;
_imageviewUnder.contentMode = UIViewContentModeLeft;
imgs = [NSArray arrayWithObjects:
#"01.jpg",
#"02.jpg",
#"03.jpg",
#"04.jpg",
#"05.jpg",
#"06.jpg",
nil];
_imgInt = (arc4random()%6);
currentImg = [imgs objectAtIndex:_imgInt];
UIImage *image = [UIImage imageNamed:currentImg];
[_imageviewUnder setImage:image];
}
- (void)viewDidAppear:(BOOL)animated{
[self initialImage];
}
- (void)initialImage
{
currentImg = [imgs objectAtIndex:_imgInt];
UIImage *image = [UIImage imageNamed:currentImg];
_starView = [[UIImageView alloc] initWithImage:image];
// Size the image view to the image (it's bigger)
_starView.bounds = CGRectMake(0.0, 44.0, 416.0, 416.0);
NSLog(#"initialImage");
_starView.alpha=1;
[self.view insertSubview:_starView atIndex:1];
int nextImgInt = _imgInt + 1 ;
if (nextImgInt>5)
{
nextImgInt=0;
}
NSString *nextImg = [imgs objectAtIndex:nextImgInt];
UIImage *nextImage = [UIImage imageNamed:nextImg];
[_imageviewUnder setImage:nextImage];
[self.view sendSubviewToBack:_imageviewUnder];
_imgInt++;
if (_imgInt>5) {
_imgInt=0;
}
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:7.6];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
//[UIView setAnimationDidStopSelector:#selector(initialImage) ];
[_starView setCenter:CGPointMake(112, 208)];
[_starView setAlpha:0.0f];
[UIView commitAnimations];
[self performSelector:#selector(initialImage) withObject:nil afterDelay:7.6];
}
- (IBAction)dismissInfo:(id)sender
{
[self cleanup];
[self dismissModalViewControllerAnimated:YES];
}
- (void)cleanup
{
[NSObject cancelPreviousPerformRequestsWithTarget:self];
[_starView.layer removeAllAnimations];
[self.view.layer removeAllAnimations];
[_starView removeFromSuperview];
}

Answer 3

If you just want to create a looping animation, the best thing to do is use the option: 'UIViewAnimationOptionRepeat'. For example:
[UIView animateWithDuration:2.0
delay:0.0f
options:UIViewAnimationOptionRepeat
animations:^{
[myUIViewThing setCenter:CGPointMake(myUIViewThing.center.x - 100, myUIViewThing.center.y)];
}
completion:nil];