After Animation, View position resets

carlos picture carlos · Oct 22, 2008 · Viewed 12.5k times · Source

I am trying to make a view slide from top to bottom. This is not a big deal, I used CABasicAnimation for this. The problem is when I want to remove the view. I use this animation.

CABasicAnimation *animation;
animation = [CABasicAnimation animationWithKeyPath:@"position"];
[animation setDelegate:self];
animation.toValue = [NSValue valueWithCGPoint:CGPointMake(self.view.layer.position.x, 0 - self.view.bounds.size.height / 2)];
animation.fromValue = [NSValue valueWithCGPoint:self.view.layer.position];
animation.autoreverses = NO;
animation.repeatCount = 0;
animation.duration = 0.25;
animation.timingFunction = [CAMediaTimingFunction functionWithName: kCAMediaTimingFunctionEaseInEaseOut];
[self.view.layer  addAnimation:animation forKey:@"moveX"];

Which animates the view perfectly. But, after the animation finishes, my view appears again. So I added this line :

[self.view removeFromSuperview];

Which removes the view, but with no animation. So I decided to add the remove code to this delegate:

-(void) animationDidStop:(CAAnimation *) animation finished:(bool) flag

So now, the animation works, the view disappears, but sometimes, I can see the view appear and disappear faster, is like after the animation, the view appears, then the animationDidStop delegate is called, and the view disappears, obviously this is awful. What am I doing wrong?

Answer

Ian Baird picture Ian Baird · Oct 30, 2008

Might want to set these properties. They cause the presentation to be preserved at the end of the animation.

animation.fillMode = kCAFillModeForwards;
animation.removedOnCompletion = NO;

Then the "animationDidStop:" method can be used to remove the view at the end of the animation:

-(void) animationDidStop:(CAAnimation *) animation finished:(bool) flag {
    if (animation == [containerView.layer animationForKey:@"moveX"]) {
        // remove view here, add another view and/or start another transition
    }
}