problem with uiimageView animation - iphone

Question

here is my code :
-(void) createNewImage {
UIImage * image = [UIImage imageNamed:#"boutonplay_03.png"];
imageView = [[UIImageView alloc] initWithImage:image];
[imageView setCenter:[self randomPointSquare]];
[[self view] addSubview:imageView];
ix=imageView.center.x;
iy=imageView.center.y;
X=(240-ix)/230;
Y=(160-iy)/230;
}
-(void)Animation{
imageView.center = CGPointMake(imageView.center.x + X, imageView.center.y + Y);
}
"CreateNewImage" is alled every 2 seconds, and there is a CADisplayLink on "Animation".
My problem is that the animation of "imageView" stops every 2 seconds because a new "imageView" is created and this last start moving and it stops again after 2 seconds, and again and again and again ... What I would like is to make "imageView" continue his animation in spite of the creation of new "imageView".How can I do this please ? sorry for my english I'm french:/

Answer 1

Check to see if imageView == nil or not.
if (imageView == nil) {
imageView = [[UIImageView alloc] initWithImage:image];
}
//rest of code

Answer 2

You are creating a new UIImageView every time you call CreateNewImage
instead, check to see if it has already been created.
-(void) createNewImage {
if(imageView == nil) {
UIImage * image = [UIImage imageNamed:#"boutonplay_03.png"];
imageView = [[UIImageView alloc] initWithImage:image];
}
[imageView setCenter:[self randomPointSquare]];
[[self view] addSubview:imageView];
ix=imageView.center.x;
iy=imageView.center.y;
X=(240-ix)/230;
Y=(160-iy)/230;
}

Answer 3

If I understand correctly your case, what happens is this:
you create a new image in createNewImage;
this image is animated through the method:
-(void)Animation{
imageView.center = CGPointMake(imageView.center.x + X, imageView.center.y + Y);
}
which animates your imageView ivar;
when you create a new image, after 2 seconds, you reassign it to the imageView ivar, so that the Animation method can animate it when it is called;
at the same time, you have lost the reference to your previous image that you were animating before, so Animation will not animate it anymore.
Now what I suggest is trying to change Animation in this way:
-(void)Animation{
for (UIView* imgView in self.view.subviews) {
imgView.center = CGPointMake(imgView.center.x + X, imgView.center.y + Y);
}
}
So, this will simply animate any subview of your main view. If your only subviews are the images you want to animate, it should be fine.
EDIT:
From your description in the comments, it seems to me that what happens is that addSubview has the effect of stopping shortly all animations. I don't know if this is related to loading the images from disk, but I remember I also experienced a similar problem time ago. The only approach I see is pre-creating and pre-adding all the UIImageViews you need (or a maximum number of allowed images), make them all hidden and then making them visible again one by one. This would make the logic of your program more complex, but it would work.
Another approach could be using CALayers instead of UIVIews. Best thing would be using a CABasicAnimation to animate your images.
If you want to use UIImageView, you could get [imageView layer] and add this one instead of the view, like this:
[[self.view layer] addSublayer:[imageView layer]];
but I am not sure that this approach would work.
Hope that his helps.