iOS5 CGAffineTransformMakeRotation doesn't work the second time I do it?

Question

I have simple rotation transformation, combined with alpha, which works perfectly on the first call, but the rotation doesn't happen the second time (the user initiates this animation by tapping the screen). Here is my basic animation function: ``` - (void) animateMe:(UIImageView *)myImage delay:(NSTimeInterval)dly { [UIView animateWithDuration:1.0 delay:dly options:UIViewAnimationOptionAutoreverse animations:^(void){ myImage.alpha = 1.0; myImage.transform = CGAffineTransformMakeRotation(180.0); } completion:^(BOOL finished) { myImage.alpha = 0.0; }]; } ```

Accepted Answer

The problem is that the second time you want to rotate the view, it is already rotated by 180 degrees and the line:

```
myImage.transform = CGAffineTransformMakeRotation(180.0);
```

is equivalent to:

```
myImage.transform = myImage.transform;
```

So you should do something like:

```
myImage.transform = CGAffineTransformRotate(myImage.transform, 180.0);
```

Note that the documentation says that the rotation angle should be in radians an not degrees. So you probably should use `M_PI` instead of `180.0`.

Also, note that the documentation says that `UIViewAnimationOptionAutoreverse` must be combined with `UIViewAnimationOptionRepeat`.

UIViewAnimationOptionAutoreverse

Run the animation backwards and forwards. Must be combined with the UIViewAnimationOptionRepeat option.

iOS5 CGAffineTransformMakeRotation doesn't work the second time I do it?

Solution

Problem