Question

I have an animation that bounces a view slightly along the x axis. The problem is that is is using the old animation mechanism and as the documentation states use of block based animations are recommended for iOS4+. I’m wondering how I can turn this simple animation into a block based animation:

[UIView beginAnimations:@"bounce" context:nil];
[UIView setAnimationRepeatCount:2];
[UIView setAnimationRepeatAutoreverses:YES];
self.view.center = CGPointMake(self.view.center.x + 10, self.view.center.y);
[UIView commitAnimations];

Also I want the view to return to its starting position after the animation ends, the method above bounces the view and increments its x value by 10 pixels.

Thanks for any help.

Answer 1

Block-base animation’s format is like this:

[UIView animateWithDuration:<#(NSTimeInterval)#>
                      delay:<#(NSTimeInterval)#>
                    options:<#(UIViewAnimationOptions)#>
                 animations:<#^(void)animations#>
                 completion:<#^(BOOL finished)completion#>];

And the code below bounces the view twice and go back to origin position, maybe there exists a better way:

[UIView animateWithDuration:0.2f
                      delay:0.0f
                    options:UIViewAnimationOptionAutoreverse | UIViewAnimationOptionCurveEaseInOut
                 animations:^{
                     self.view.center = CGPointMake(self.view.center.x + 10, self.view.center.y);
                 }
                 completion:^(BOOL finished) {
                     self.view.center = CGPointMake(self.view.center.x - 10, self.view.center.y);
                     [UIView animateWithDuration:0.2f
                                           delay:0.0f
                                         options:UIViewAnimationOptionAutoreverse | UIViewAnimationOptionCurveEaseInOut
                                      animations:^{
                                          self.view.center = CGPointMake(self.view.center.x + 10, self.view.center.y);
                                      }
                                      completion:^(BOOL finished) {
                                          self.view.center = CGPointMake(self.view.center.x - 10, self.view.center.y);
                                      }];
                 }];

And this one is similar, but go back to origin position not smoothly.

[UIView animateWithDuration:0.2f
                      delay:0.0f
                    options:UIViewAnimationOptionAutoreverse | UIViewAnimationOptionCurveEaseInOut
                 animations:^{
                     self.view.center = CGPointMake(self.view.center.x + 10, self.view.center.y);
                     self.view.center = CGPointMake(self.view.center.x - 10, self.view.center.y);
                 }
                 completion:nil];