UIView animation lags on device - ios

Question

I'm using animation in my app and get confused, because animation is lagging on device, on simulator everything seems OK. First I tried to use
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.3];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
And before commit animation there were something like ~30 lines of code with "if" blocks so I thought this might cause the problem, but then I start to use
[UIView animateWithDuration:0.3
delay:0.0
options: UIViewAnimationCurveEaseIn
animations:^{
mainView.frame = CGRectMake(0, 0, 320, 420);
buttonsView.transform = CGAffineTransformMakeTranslation(0, 68);
radioBar.transform = CGAffineTransformMakeTranslation(0, -50);
vk_controller.view.frame = CGRectMake(0, 0, 320, 440);
}
completion:^(BOOL finished){
button.isHiddenDown = YES;
}];
in terms of "if" blocks, but lags seems to stay. When I press button there is delay ~0.5-1 sec (why?) and then animation starts. But when I'm on table view
[UIView animateWithDuration:0.3
delay:0.0
options: UIViewAnimationCurveEaseIn
animations:^{
mainView.frame = CGRectMake(0, 0, 320, 420);
buttonsView.transform = CGAffineTransformMakeTranslation(0, 68);
radioBar.transform = CGAffineTransformMakeTranslation(0, -50);
goha_news_controller.view.frame = CGRectMake(0, 0, 320, 420);
goha_news_controller.feed_table.frame = CGRectMake(0, 0, 320, 420);
if(goha_news_controller.backgroundView)
{
goha_news_controller.backgroundView.frame = CGRectMake(0, 0, 320, 420);
goha_news_controller.newsDetailView.frame = CGRectMake(0, 0, 320, 420);
}
}
completion:^(BOOL finished){
button.isHiddenDown = YES;
}];
in addition to the unexpected delay before the animation, there is harshness animation with bursts.
Can anyone explain why does it happen and how can I fix it?

Answer 1

Another possible cause. Are you using shadows in any of the on-screen views or layers? iOS does not handle animating with shadows very well at all.

Answer 2

You cannot use the simulator to gauge performance. It has completely different (not just better or worse) performance characteristics than a device (and the devices also differ from generation to generation).
If statements are not causing significant delay; they are very cheap.
Your performance problems probably lie elsewhere. I can't see anything in the code you've shown us that looks like an obvious performance problem.

Answer 3

If you resize images in controls while animation, this can cause lags, because image resizing is a very expensive process for CPU. You should make thumbnails of images before you run animation and change images.
Also, try to use Begin animations - commit animations instead of animating using blocks.
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.75];
// Here some more animation settings
// Here your animations
[UIView commitAnimations];