如何连续几次为 UIImageView 旋转设置动画

Question

我正在尝试为 UIImage 视图设置动画，每次顺时针旋转 90 度。 出于某种原因，第一个旋转动画有效，但随后它停止了（即使另一个视图调整大小动画继续有效）。这是为什么？ （我到处找，但找不到答案）

{
        [btn setFrame:CGRectMake(previousX, previousY, BUTTON_WIDTH, BUTTON_HEIGHT)];
        [self.view insertSubview:btn atIndex:0];

        [UIView beginAnimations:@"ButtonAnimation" context:nil];

        [UIView setAnimationDuration:2.5];

        [UIView setAnimationCurve:UIViewAnimationCurveLinear];

        CGRect rect = CGRectMake(previousX,previousY+BUTTON_HEIGHT,BUTTON_WIDTH,BUTTON_HEIGHT);

         btn.frame = rect;

        [UIView setAnimationBeginsFromCurrentState:YES]; 

        ++ButtonCounter;
         if (ButtonCounter < [btnArray count])
            {

                [UIView setAnimationDidStopSelector:@selector(didStopReal)];
            }
            else
            {
                ButtonCounter = 0; 
            }


        // The transform matrix
        CGAffineTransform transform = 
        CGAffineTransformMakeRotation(DEGREES_TO_RADIANS(90));

        imgArrowView.transform = transform;


        [UIView setAnimationDelegate:self];
        [UIView commitAnimations];
}

-(void) didStopReal
{
    [self animteReal:ButtonCounter];
}

Answer 1

构建相对于当前变换的变换矩阵：

CGAffineTransform transform = 
CGAffineTransformRotate(imgArrowView.transform, DEGREES_TO_RADIANS(90));