CAKeyframeAnimation从最后一个点重复旋转

Question

在我的iPhone应用程序中,我有一个UIButton,当我按下另一个UIButton时,我旋转180度进入视图,然后再次点击时按钮再旋转180度回到它开始的位置.

这一切都在第一次完成360度全过程时工作正常,但是如果我尝试从头开始再次开始它会弹开180度然后尝试从那一点旋转它.谁能指出我正确的方向？这是我到目前为止的代码......

showAnimation= [CAKeyframeAnimation animationWithKeyPath:@"transform.rotation"];
                    showAnimation.duration = self.showAnimationDuration;
                    showAnimation.repeatCount = 1;
                    showAnimation.fillMode = kCAFillModeForwards;
                    showAnimation.removedOnCompletion = NO;
                    showAnimation.cumulative = YES;
                    showAnimation.delegate = self;

float currentAngle =[[[rotateMe.layer presentationLayer] valueForKeyPath:@"transform.rotation.z"] floatValue];

//Rotate 180 degrees from current rotation
showAnimation.values = [NSArray arrayWithObjects:       
                        [NSNumber numberWithFloat:currentAngle],
                        [NSNumber numberWithFloat:currentAngle + (0.5 * M_PI)],
                        [NSNumber numberWithFloat:currentAngle + M_PI], nil];

[rotateMe.layer addAnimation:showAnimation forKey:@"show"];

完成动画后,我将rotateMe.transform旋转更新为图层的旋转,以使其可用.

- (void)animationDidStop:(CAKeyframeAnimation *)anim finished:(BOOL)flag
{
    float currentAngle =[[[self.layer presentationLayer] valueForKeyPath:@"transform.rotation.z"] floatValue];

    NSLog(@"End: %f", currentAngle);
    rotateMe.transform = CGAffineTransformMakeRotation(0);
}

我已经取得了充分的工作效果

    [UIView animateWithDuration:1.0f]
        animations:^{
            CGAffineTransform transform = CGAffineTransformRotate(rotateMe.transform, DEGREES_TO_RADIANS(179.999f));
            rotateMe.transform = transform;
        }
     ];

但我想使动画更复杂,因此CAKeyframeAnimation.

Answer 1

additive如果需要所有关键帧,可以将动画配置为0到180度的动画.如果您不需要不同的关键帧,您只需使用基本动画和byValue属性即可.下次添加动画时,它会比视图上的任何旋转旋转180度.

如果要在委托回调中设置实际值,则不需要填充模式,也不需要在完成时删除动画.

CABasicAnimation *showAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
showAnimation.byValue = M_PI;
showAnimation.duration = self.showAnimationDuration;
showAnimation.delegate = self;

[rotateMe.layer addAnimation:showAnimation forKey:@"show"];

或使用关键帧动画(如上所述:使其成为0至180度的加法和动画).

CAKeyframeAnimation *showAnimation = [CAKeyframeAnimation animationWithKeyPath:@"transform.rotation.z"];
showAnimation.additive = YES; // Make the values relative to the current value
showAnimation.values = @[0, /*all your intermediate values here... ,*/ M_PI];
showAnimation.duration = self.showAnimationDuration;
showAnimation.delegate = self;

[rotateMe.layer addAnimation:showAnimation forKey:@"show"];