Question

I simply can’t get this to work, I would think it was simple, but no luck.

- (void) animate {

    UIView *viewA = [[UIView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 300.0f, 100.0f)];
    [viewA setBackgroundColor:[UIColor blueColor]];
    UIView *viewB = [[UIView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 300.0f, 100.0f)];
    [viewB setBackgroundColor:[UIColor brownColor]];

    UIView *container = [[UIView alloc] initWithFrame:CGRectMake(10.0f, 10.0f, 300.0f, 100.0f)];
    [container addSubview:viewA];

    [self.view addSubview:container];

    [UIView transitionWithView:container
                      duration:0.4
                       options:UIViewAnimationOptionTransitionFlipFromLeft
                    animations:^{
                        [[[container subviews] objectAtIndex:0] removeFromSuperview];
                        [container addSubview:viewB];
                    }
                    completion:^(BOOL finished){

                    }];


}

This is how the documentation recommends you do it, make a container, add/remove the two subviews you want to flip between.

I can’t get it to work. It will just display viewA, then viewB, as if the animation part is skipped, but the block is carried out?

If I switch the container in the [UIView transitionWithView:container with self.view it flips the entire view (As suspected) but I can not get it to do this with 2 subviews of self.view.

Is there no way around this?

I am looking to do something like the iPad Photos app, where a picture will flip and scale to full screen.

I really hope someone could help me out here, thank you in advance.

Answer 1

You can’t put semicolons inside the block. If you want two things done in there, divide them with a “,”.
Also CurveEase would probably be nice., if you want it.

This should work.

[UIView transitionWithView:container
                  duration:0.4
                   options:UIViewAnimationOptionTransitionFlipFromLeft | UIViewAnimationOptionCurveEaseInOut
                animations:^{
                    [[[container subviews] objectAtIndex:0] removeFromSuperview],
                    [container addSubview:viewB];
                }
                completion:^(BOOL finished){

                }];

If it does not, consider making the views instance variables and make sure they’re allocated before you try to animate them. If you want to animate on a button push, you can do it directly with sender too, if the whole view is a UIButton.

I hope it helps.