用pop创建无尽的动画？

Question

使用Coreanimation框架时，我可以设置动画重复播放。 我想将按钮设置为“吸引注意力”模式，这应该会使他少量成长和收缩以引起用户的注意。

我已经通过完成块链接了生长和收缩动画。 问题是，是否以及如何从第二个动画的完成块开始第一个动画。

我确实收到以下警告，这确实是有道理的。 有什么绝妙的解决方案？ 我不喜欢为此类事件创建计时器。

在此块中强烈捕获“ scaleAnimation”可能会导致保留周期

- (void)attractAttention:(BOOL)flag{
    _attractAttention = flag;
    float resizeValue = 1.2f;

        // Grow animation
    POPSpringAnimation *scaleAnimation = [POPSpringAnimation animationWithPropertyNamed:kPOPLayerScaleXY];
    scaleAnimation.fromValue  = [NSValue valueWithCGSize:CGSizeMake(1.0f, 1.0f)];
    scaleAnimation.toValue  = [NSValue valueWithCGSize:CGSizeMake(resizeValue, resizeValue)];
    scaleAnimation.completionBlock = ^(POPAnimation *anim, BOOL finished) {
            // Grow animation done
        POPSpringAnimation *scaleAnimationDown = [POPSpringAnimation animationWithPropertyNamed:kPOPLayerScaleXY];
        scaleAnimationDown.fromValue  = [NSValue valueWithCGSize:CGSizeMake(resizeValue, resizeValue)];
        scaleAnimationDown.toValue  = [NSValue valueWithCGSize:CGSizeMake(1.0f, 1.0f)];

        scaleAnimationDown.completionBlock = ^(POPAnimation *anim, BOOL finished) {
                // Shrink animation done
            if (_attractAttention) {
                [self.layer pop_addAnimation:scaleAnimation forKey:@"scaleUpAnimation"];
            }
        };

        [self.layer pop_addAnimation:scaleAnimationDown forKey:@"scaleDownAnimation"];
    };

    [self.layer pop_addAnimation:scaleAnimation forKey:@"scaleUpAnimation"];
}

编辑：

我还尝试创建该动画的弱引用。 这样可以消除错误，但是动画不再起作用：

__weak typeof(scaleAnimation) weakAnimation = scaleAnimation;

Answer 1

您还可以使用属性autoreveres和repeatCount来获得相同的结果，而无需使用块。 它降低了复杂性：

POPSpringAnimation *scaleAnimation = [POPSpringAnimation animationWithPropertyNamed:kPOPLayerScaleXY];
scaleAnimation.toValue = [NSValue valueWithCGSize:CGSizeMake(0.5, 0.5)];
scaleAnimation.springBounciness = 0.f;
scaleAnimation.autoreverses = YES;
scaleAnimation.repeatCount=HUGE_VALF;
[layer pop_addAnimation:scaleAnimation forKey:@"scale"];

更好的是，如果您检查此类https://github.com/facebook/pop/blob/master/pop/POPAnimation.h，您将看到有一个repeatForever属性，因此您可以用它替换repeatCount：

scaleAnimation.repeatForever=YES;

Answer 2

编辑：请勿使用此解决方案。 POP框架已更新为“重复”标志。 当我第一次遇到此问题时，它不可用。

---

我通过一个非常简单的解决方法解决了它：

- (void)attractAttention:(BOOL)flag{
    _attractAttention = flag;
    if (_attractAttention){
        [self animatePop];
    }
}


- (void)animatePop{
    float resizeValue = 1.2f;

        // Grow animation
    POPSpringAnimation *scaleAnimation = [POPSpringAnimation animationWithPropertyNamed:kPOPLayerScaleXY];

    scaleAnimation.fromValue  = [NSValue valueWithCGSize:CGSizeMake(1.0f, 1.0f)];
    scaleAnimation.toValue  = [NSValue valueWithCGSize:CGSizeMake(resizeValue, resizeValue)];
    scaleAnimation.completionBlock = ^(POPAnimation *anim, BOOL finished) {
            // Grow animation done
        POPSpringAnimation *scaleAnimationDown = [POPSpringAnimation animationWithPropertyNamed:kPOPLayerScaleXY];
        scaleAnimationDown.fromValue  = [NSValue valueWithCGSize:CGSizeMake(resizeValue, resizeValue)];
        scaleAnimationDown.toValue  = [NSValue valueWithCGSize:CGSizeMake(1.0f, 1.0f)];

        scaleAnimationDown.completionBlock = ^(POPAnimation *anim, BOOL finished) {
                // Shrink animation done
            if (_attractAttention) {
                [self animatePop];
            }
        };

        [self.layer pop_addAnimation:scaleAnimationDown forKey:@"scaleDownAnimation"];
    };

    [self.layer pop_addAnimation:scaleAnimation forKey:@"scaleUpAnimation"];
}