Animate UIView height from bottom to top

Question

I'm doing a simple animation of UIView height so that it reveals.

By default it seems to be revealing from top to bottom, and I want it to reveal bottom to top.

I have the UIView anchored to the bottom of the screen.

I'm sure it something simple i'm missing..... any tips?

Thanks

Answer 1

Instead you could try putting it in a view with clipsToBounds = YES and then animate it from the bottom to the middle of the view, like so:

viewToAnimate.frame = CGRectMake(viewToAnimate.frame.origin.x,
                                 viewToAnimate.superview.frame.size.height,
                                 viewToAnimate.frame.size.width,
                                 viewToAnimate.frame.size.height);

[UIView animateWithDuration:0.5 animations:^{
     viewToAnimate.center = viewToAnimate.superview.center;
}];

This way, you don't have to set the height to 0, and it solves any problems with autoresizing within the view.

Answer 2

I really think the simplest way to accomplish this would be to animate BOTH the height and the y properties of the view. If they happen along the same curve, it should look completely seamless to the user. As you are animating the height to 0, also animate the y component to the original y + the original height.

UIView *view = ...;
float originalY = view.frame.origin.y;
float originalH = view.bounds.size.height;

[UIView animateWithDuration:1.2f delay:1.0f options:UIViewAnimationCurveEaseInOut animations:^{
    view.frame = CGRectMake(view.frame.origin.x, (originalY + originalH), view.bounds.size.width, 0);

}completion:^(BOOL finished) {
    NSLog(@"Animation is complete");
}];

I believe this would give the look and feel of a collapsing view. I haven't tried this out in code, but I see no reason why it wouldn't be possible like this.

Answer 3

hide under bottom

[self animateViewHeight:myView withAnimationType:kCATransitionFromBottom];

for reverse animation

[self animateViewHeight:myView withAnimationType:kCATransitionFromTop];

...

- (void)animateViewHeight:(UIView*)animateView withAnimationType:(NSString*)animType {  
    CATransition *animation = [CATransition animation];
    [animation setType:kCATransitionPush];
    [animation setSubtype:animType];

    [animation setDuration:0.5];
    [animation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
    [[animateView layer] addAnimation:animation forKey:kCATransition];
    animateView.hidden = !animateView.hidden;
}