iOS-CALayer上的动画 如何暂停和恢复?

把正在闪烁的动画暂停

-重点看暂停和恢复的操作

这个maskLayer 是你定义的属性(就是你哪个控件在做动画操作)

//开始动画
- (void)startShimmer {
    dispatch_async(dispatch_get_main_queue(), ^{
        // 切换到主线程串行队列，下面代码打包成一个事件（原子操作），加到runloop，就不用担心 isPlaying 被多个线程同时修改
        // dispatch_async() 不 strong 持有本 block，也不用担心循环引用
        if (self.isPlaying == true) return ;
        self.isPlaying = true;
        [self copyLabel:self.maskLabel from:self.contentLabel];
        self.maskLabel.hidden = false;
        [self.maskLayer removeFromSuperlayer];
        [self freshMaskLayer];
        [self.maskLabel.layer addSublayer:self.maskLayer];
        self.maskLabel.layer.mask = self.maskLayer;
        
        switch (self.shimmerType) {
            case ST_LeftToRight: {
                self.maskLayer.transform = self.startT;
                self.translate.fromValue = [NSValue valueWithCATransform3D:self.startT];
                self.translate.toValue = [NSValue valueWithCATransform3D:self.endT];
                [self.maskLayer removeAllAnimations];
                [self.maskLayer addAnimation:self.translate forKey:@"start"];
                break;
            }
            case ST_RightToLeft: {
                self.maskLayer.transform = self.endT;
                self.translate.fromValue = [NSValue valueWithCATransform3D:self.endT];
                self.translate.toValue = [NSValue valueWithCATransform3D:self.startT];
                [self.maskLayer removeAllAnimations];
                [self.maskLayer addAnimation:self.translate forKey:@"start"];
                break;
            }
            case ST_AutoReverse : {
                self.maskLayer.transform = self.startT;
                self.translate.fromValue = [NSValue valueWithCATransform3D:self.startT];
                self.translate.toValue = [NSValue valueWithCATransform3D:self.endT];
                [self.maskLayer removeAllAnimations];
                [self.maskLayer addAnimation:self.translate forKey:@"start"];
                break;
            }
            case ST_ShimmerAll : {
                self.maskLayer.transform = CATransform3DIdentity;
                [self.maskLayer removeAllAnimations];
                [self.maskLayer addAnimation:self.alphaAni forKey:@"start"];
                break;
            }
            default: break;
        }
    });
}


//暂停动画
-(void)pauseLayer{
    dispatch_async(dispatch_get_main_queue(), ^{
        if (self.isPlaying == false) return ;
        self.isPlaying = false;
        CFTimeInterval pausedTime = [self.maskLayer  convertTime:CACurrentMediaTime() fromLayer:nil];
        self.maskLayer.speed = 0.0;
        self.maskLayer.timeOffset = pausedTime;
        
    });
}


//继续动画
-(void)resumeLayer{
    CFTimeInterval pausedTime = [self.maskLayer timeOffset];
    self.maskLayer.speed = 1.0;
    self.maskLayer.timeOffset = 0.0;
    self.maskLayer.beginTime = 0.0;
    CFTimeInterval timeSincePause = [self.maskLayer convertTime:CACurrentMediaTime() fromLayer:nil] - pausedTime;
    self.maskLayer.beginTime = timeSincePause;
}


//结束动画
- (void)stopShimmer {
    dispatch_async(dispatch_get_main_queue(), ^{
        if (self.isPlaying == false) return ;
        self.isPlaying = false;
        
        [self.maskLayer removeAllAnimations];
        [self.maskLayer removeFromSuperlayer];
        self.maskLabel.hidden = true;
    });
}

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