Shake visual effect on iPhone (NOT shaking the device)

Question

On login failure, I\'d prefer to avoid showing an alert, it\'s too fleeting. Showing the alert and then showing the text somewhere on the login screen seems like duplication

Answer 1

Using iOS 4+ block based UIKit animations (and loosely based on on jayccrown's answer):

- (void)shakeView:(UIView *)viewToShake
{
    CGFloat t = 2.0;
    CGAffineTransform translateRight  = CGAffineTransformTranslate(CGAffineTransformIdentity, t, 0.0);
    CGAffineTransform translateLeft = CGAffineTransformTranslate(CGAffineTransformIdentity, -t, 0.0);

    viewToShake.transform = translateLeft;

    [UIView animateWithDuration:0.07 delay:0.0 options:UIViewAnimationOptionAutoreverse|UIViewAnimationOptionRepeat animations:^{
        [UIView setAnimationRepeatCount:2.0];
        viewToShake.transform = translateRight;
    } completion:^(BOOL finished) {
        if (finished) {
            [UIView animateWithDuration:0.05 delay:0.0 options:UIViewAnimationOptionBeginFromCurrentState animations:^{
                viewToShake.transform = CGAffineTransformIdentity;
            } completion:NULL];
        }
    }];
}