iPhone UIView Animation Best Practice

Question

What is considered best practice for animating view transitions on the iPhone?

For example, the ViewTransitions sample project from apple uses code like:

CATransition *applicationLoadViewIn = [CATransition animation];
[applicationLoadViewIn setDuration:1];
[applicationLoadViewIn setType:kCATransitionReveal];
[applicationLoadViewIn setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn]];
[[myview layer] addAnimation:applicationLoadViewIn forKey:kCATransitionReveal];

but there are also code snippets floating around the net that look like this:

[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.75];
[UIView setAnimationDelegate:self];
[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:myview cache:YES];
[myview removeFromSuperview];
[UIView commitAnimations];

What is the best approach? If you could provide a snippet as well it'd be much appreciated.

NOTE: I've been unable to get the second approach to work correctly.

Answer 1

Anyway the "Block" method is preffered now-a-days. I will explain the simple block below.

Consider the snipped below. bug2 and bug 3 are imageViews. The below animation describes an animation with 1 second duration after a delay of 1 second. The bug3 is moved from its center to bug2's center. Once the animation is completed it will be logged "Center Animation Done!".

-(void)centerAnimation:(id)sender
{
NSLog(@"Center animation triggered!");
CGPoint bug2Center = bug2.center;

[UIView animateWithDuration:1
                      delay:1.0
                    options: UIViewAnimationCurveEaseOut
                 animations:^{
                     bug3.center = bug2Center;
                 } 
                 completion:^(BOOL finished){
                     NSLog(@"Center Animation Done!");
                 }];
}

Hope that's clean!!!

Answer 2

I found a good tutorial in this link. Hope this will be helpful for some one.

uiview-animation-tutorial

Answer 3

I have been using the latter for a lot of nice lightweight animations. You can use it crossfade two views, or fade one in in front of another, or fade it out. You can shoot a view over another like a banner, you can make a view stretch or shrink... I'm getting a lot of mileage out of beginAnimation/commitAnimations.

Don't think that all you can do is:

[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:myview cache:YES];

Here is a sample:

[UIView beginAnimations:nil context:NULL]; {
    [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
    [UIView setAnimationDuration:1.0];
    [UIView setAnimationDelegate:self];
    if (movingViewIn) {
// after the animation is over, call afterAnimationProceedWithGame
//  to start the game
        [UIView setAnimationDidStopSelector:@selector(afterAnimationProceedWithGame)];

//      [UIView setAnimationRepeatCount:5.0]; // don't forget you can repeat an animation
//      [UIView setAnimationDelay:0.50];
//      [UIView setAnimationRepeatAutoreverses:YES];

        gameView.alpha = 1.0;
        topGameView.alpha = 1.0;
        viewrect1.origin.y = selfrect.size.height - (viewrect1.size.height);
        viewrect2.origin.y = -20;

        topGameView.alpha = 1.0;
    }
    else {
    // call putBackStatusBar after animation to restore the state after this animation
        [UIView setAnimationDidStopSelector:@selector(putBackStatusBar)];
        gameView.alpha = 0.0;
        topGameView.alpha = 0.0;
    }
    [gameView setFrame:viewrect1];
    [topGameView setFrame:viewrect2];

} [UIView commitAnimations];

As you can see, you can play with alpha, frames, and even sizes of a view. Play around. You may be surprised with its capabilities.

Answer 4

We can animate images in ios 5 using this simple code.

CGRect imageFrame = imageView.frame;
imageFrame.origin.y = self.view.bounds.size.height;

[UIView animateWithDuration:0.5
    delay:1.0
    options: UIViewAnimationCurveEaseOut
    animations:^{
        imageView.frame = imageFrame;
    } 
    completion:^(BOOL finished){
        NSLog(@"Done!");
    }];

Answer 5

In the UIView docs, have a read about this function for ios4+

+ (void)transitionFromView:(UIView *)fromView toView:(UIView *)toView duration:(NSTimeInterval)duration options:(UIViewAnimationOptions)options completion:(void (^)(BOOL finished))completion

Answer 6

From the UIView reference's section about the beginAnimations:context: method:

Use of this method is discouraged in iPhone OS 4.0 and later. You should use the block-based animation methods instead.

Eg of Block-based Animation based on Tom's Comment

[UIView transitionWithView:mysuperview 
                  duration:0.75
                   options:UIViewAnimationTransitionFlipFromRight
                animations:^{ 
                    [myview removeFromSuperview]; 
                } 
                completion:nil];