iOS setAnimationDidStopSelector方法导致崩溃

Question

I have created a UIView animation use the below code, usually it works fine, but occasionally it will crash with:

EXC_BAD_ACCESS(code=2,address=0xcc)

 -(void)continueAnimation
{   
    [button setImage:[UIImage imageNamed:REFRESHING_IMAGE] forState:UIControlStateNormal];
    if (leastTime <= 0) {
        leastTime += 360;
    }   
    leastTime -= 10;
    angle += 10;
    angle %= 360;
    [button setEnabled:NO];
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.01];
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDidStopSelector:@selector(continueAnimation)];
    button.transform = CGAffineTransformMakeRotation(angle * (M_PI / 180.0f));
    [UIView commitAnimations];
}

Answer 1

EXC_BAD_ACCESS means that something was released, but you still have pointer to that memory, and when you try to send message to this invalid pointer it crashes.

• (void)setAnimationDelegate:(id _Nullable)delegate Description

Sets the delegate for any animation messages. An object that defines the methods registered using the setAnimationWillStartSelector: and setAnimationDidStopSelector: methods. The view maintains a strong reference to this object for the duration of the animation.

In you case view will have strong ref to itself and that's bad. Looks like application crashes because sometimes animation releases ref to animationDelegate before it get setted to setAnimationDelegate because of some lag or something.

Anyway * try to avoid such a way of animation, use blocks * try to pass __weak typeof(self) wSelf = self; to any delegates and inside blocks * looks like you have no way to stop that animation and also application leaks

to make infinit rotation of image you can simply do:

    CABasicAnimation* rotationAnimation;

    rotationAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
    rotationAnimation.toValue = [NSNumber numberWithFloat: M_PI * 2.0];
    rotationAnimation.duration = 1;
    rotationAnimation.cumulative = YES;
    rotationAnimation.repeatCount = HUGE_VALF;
    [self.spinnerImg.layer addAnimation:rotationAnimation forKey:@"rotationAnimation"];

just keep in mind that you have restart it on returning from background or presenting view, for example after pop to viewcontroller