IOS: How to detect animation is in progress - ios

Question

This has been asked before but none of the answers are straightforward enough to help little old me.
What exactly does .isAnimating in an UIIimage view do? And how to properly use it?
I am emulating the tap to focus animation in the iPhone camera (yellowish square that pops up and then shrinks when you tap on the preview). That works fine, but I want it to not happen multiple times if it is already animating. This code does the animation but multiple taps gives multiple animationed squares. I suspect it is not just .isAnimating but I'm also doing something else wrong because I tried it with my own boolean too and that fails.
-(void)focusSquarePopUp:(CGPoint)touchPoint;
{
UIImage *focusSquareImage = [UIImage imageNamed:#"yellowFocusSquare"];
UIImageView *tmpView = [[UIImageView alloc] initWithImage:focusSquareImage];
if (!(tmpView.isAnimating))
{
tmpView.center = touchPoint;
tmpView.opaque = YES;
tmpView.alpha = 1.0f;
[self.view addSubview:tmpView];
tmpView.hidden = NO;
// shrink to half size in .3 second
[UIView animateWithDuration:0.3 delay:0 options:0 animations:^{
tmpView.transform = CGAffineTransformMakeScale(.5, .5);
NSLog(#"in animation isAnimating %hhd", tmpView.isAnimating);
} completion:^(BOOL finished) {
// Once the animation is completed hide the view for good
tmpView.hidden = YES;
}];
}
NSLog(#"done animating isAnimating %hhd", tmpView.isAnimating);
[tmpView release];
}
If there is question where this has a solid answer, that would be great.
EDIT - here is the working code.
-(void)focusSquarePopUp:(CGPoint)touchPoint;
{
if (animationInProgress)
return;
animationInProgress = true;
UIImageView *tmpView = [[UIImageView alloc] initWithImage:sp_ui->focus_square];
tmpView.center = touchPoint;
tmpView.opaque = YES;
tmpView.alpha = 1.0f;
[self.view addSubview:tmpView];
tmpView.hidden = NO;
// shrink to half size in .3 second
[UIView animateWithDuration:0.3 delay:0 options:0 animations:^{
tmpView.transform = CGAffineTransformMakeScale(.5, .5);
} completion:^(BOOL finished) {
// Once the animation is completed hide the view for good
tmpView.hidden = YES;
animationInProgress = false;
}];
[tmpView release];
}

Answer 1

I suspect on your code. On your tapping on method focusSquarePopUp: you create new instances of tmpView and focusSquareImage and it adding on self view. That why you found number of animated square equal to number of tap. When you create new instance of those variable then sure isAnimating is firstly you got NO value and it enter animation block code.
Why not you create instance of tmpView and focusSquareImage in .h file of class?? In fact its problem of variable declarations and scope of variables.
Your code should be like this,
Declare instance in animation class (i.e. self.view) .h file
UIImage *focusSquareImage;
UIImageView *tmpView;
Now in .m file viewDidLoad method,
in viewDidLoad
focusSquareImage = [UIImage imageNamed:#"yellowFocusSquare"];
tmpView = [[UIImageView alloc] initWithImage:focusSquareImage];
Your animation method implementation should be,
-(void)focusSquarePopUp:(CGPoint)touchPoint;
{
if (!(tmpView.isAnimating))
{
tmpView.center = touchPoint;
tmpView.opaque = YES;
tmpView.alpha = 1.0f;
[self.view addSubview:tmpView];
tmpView.hidden = NO;
// shrink to half size in .3 second
[UIView animateWithDuration:0.3 delay:0 options:0 animations:^{
tmpView.transform = CGAffineTransformMakeScale(.5, .5);
NSLog(#"in animation isAnimating %hhd", tmpView.isAnimating);
} completion:^(BOOL finished) {
// Once the animation is completed hide the view for good
tmpView.hidden = YES;
[tmpView release];
}];
}
}
Another option of method implementation,
-(void)focusSquarePopUp:(CGPoint)touchPoint;
{
if(!tmpView){
focusSquareImage = [UIImage imageNamed:#"yellowFocusSquare"];
tmpView = [[UIImageView alloc] initWithImage:focusSquareImage];
if (!(tmpView.isAnimating))
{
tmpView.center = touchPoint;
tmpView.opaque = YES;
tmpView.alpha = 1.0f;
[self.view addSubview:tmpView];
tmpView.hidden = NO;
// shrink to half size in .3 second
[UIView animateWithDuration:0.3 delay:0 options:0 animations:^{
tmpView.transform = CGAffineTransformMakeScale(.5, .5);
NSLog(#"in animation isAnimating %hhd", tmpView.isAnimating);
} completion:^(BOOL finished) {
// Once the animation is completed hide the view for good
tmpView.hidden = YES;
[tmpView release];
tmpView = nil;
}];
}
}
}

Answer 2

isAnimating is UIImageView property and it has nothing to do with UIView animation methods
isAnimating is used when you want a UIImageView to alternate between multiple images. For example in the following code the UIImageView display 3 images and alternate between them
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 40, 40)];
UIImage *image1 = [UIImage imageNamed:#"image1.png"];
UIImage *image2 = [UIImage imageNamed:#"image2.png"];
UIImage *image3 = [UIImage imageNamed:#"image3.png"];
imageView.animationImages = #[image1, image2, image3];
imageView.animationDuration = 1;
NSLog(#"isAnimating %d",imageView.isAnimating); // isAnimating 0
[imageView startAnimating];
NSLog(#"isAnimating %d",imageView.isAnimating); // isAnimating 1
[self.view addSubview:imageView];
Your case is completely different you are using UIView animation blocks and to know if the animation in its block is finished or not you will need to add a Boolean flag instance variable animationFinished and set it to YES in the completion block of the animation