Question

我正在旋转UIBarButtonItem。动画工作得很好。但是，当我从服务器接收数据时，我想平稳地停止动画。

我尝试使用presentationLayer捕获当前值，但我得到的只是0。

- (void)animateLeftBarButtonItem
{
    //Animate Button
    CABasicAnimation *leftBarButtonItemRotator = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
    leftBarButtonItemRotator.delegate = self;
    leftBarButtonItemRotator.removedOnCompletion = NO;
    leftBarButtonItemRotator.fillMode = kCAFillModeForwards;
    leftBarButtonItemRotator.duration = 5.0;
    leftBarButtonItemRotator.fromValue = @0.0f;
    leftBarButtonItemRotator.toValue = @(50*(-2.0f * M_PI));
    leftBarButtonItemRotator.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
    [self.navigationItem.leftBarButtonItem.customView.layer addAnimation:leftBarButtonItemRotator forKey:@"leftBarButtonRotation"];

}

有什么建议吗？

此致

Answer 1

好的，我非常需要这个，我花了一个小时尝试不同的黑客。

下一个想法似乎有效。它基于以下事实：似乎每个动画都添加到一个图层（即使它在同一个属性上运行），CA混合它。所以我们开始另一个具有相同属性的动画，因为我们希望它们淡出它们。完成后我们删除前一个。

我接下来提供的示例中有几个关键部分。我加粗了他们。

希望它有所帮助。


-(void)slowBeat{


    //check if animations alredy running?

    [CATransaction begin];

    CAKeyframeAnimation* zoom = [CAKeyframeAnimation animationWithKeyPath:@"transform.scale"];
    zoom.duration = 1.0f;
    zoom.speed = .75f;
    zoom.repeatCount = INFINITY;
    zoom.fillMode = kCAFillModeForwards;
    zoom.removedOnCompletion = YES;
    zoom.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
    zoom.calculationMode = kCAAnimationCubicPaced;
    zoom.keyTimes = [NSArray arrayWithObjects:
                     [NSNumber numberWithFloat:0.0f],
                     [NSNumber numberWithFloat:0.80f],
                     [NSNumber numberWithFloat:0.95f],
                     [NSNumber numberWithFloat:1.0f], nil];

    zoom.values = [NSArray arrayWithObjects:
                   [NSNumber numberWithFloat:1.0f],
                   [NSNumber numberWithFloat:1.0f],
                   [NSNumber numberWithFloat:1.3f],
                   [NSNumber numberWithFloat:1.0f], nil];
    [self.contentWrapper.layer addAnimation:zoom forKey:@"slowBeatPosition"];

    CAKeyframeAnimation* fadeInAndOut = [CAKeyframeAnimation animationWithKeyPath:@"backgroundColor"];
    fadeInAndOut.duration = 1.0f;
    fadeInAndOut.speed = .75f;
    fadeInAndOut.repeatCount = INFINITY;
    fadeInAndOut.fillMode = kCAFillModeForwards;
    fadeInAndOut.removedOnCompletion = YES;
    fadeInAndOut.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
    fadeInAndOut.calculationMode = kCAAnimationCubicPaced;
    fadeInAndOut.keyTimes = [NSArray arrayWithObjects:
                             [NSNumber numberWithFloat:0.0f],
                             [NSNumber numberWithFloat:0.80f],
                             [NSNumber numberWithFloat:0.95f],
                             [NSNumber numberWithFloat:1.0f], nil];

    fadeInAndOut.values = [NSArray arrayWithObjects:
                           (id)[UIColor colorWithWhite:1.0f alpha:0.1f].CGColor,
                           (id)[UIColor colorWithWhite:1.0f alpha:0.1f].CGColor,
                           (id)[UIColor colorWithWhite:1.0f alpha:0.7f].CGColor,
                           (id)[UIColor colorWithWhite:1.0f alpha:0.1f].CGColor, nil];
    [self.redView.layer addAnimation:fadeInAndOut forKey:@"slowBeatColor"];
    [CATransaction commit];

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3.4 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{


        [CATransaction begin];
        [CATransaction setCompletionBlock:^{
            [self.contentWrapper.layer removeAnimationForKey:@"slowBeatPosition"];
            [self.redView.layer removeAnimationForKey:@"slowBeatColor"];
            [self.contentWrapper.layer removeAnimationForKey:@"slowBeatPosition2"];
            [self.redView.layer removeAnimationForKey:@"slowBeatColor2"];
        }];
        CABasicAnimation* zoom2 = [CABasicAnimation animationWithKeyPath:@"transform"];
        zoom2.duration = 0.4f;
        zoom2.speed = 1.0f;
        zoom2.repeatCount = 1;
        zoom2.fillMode = kCAFillModeForwards;
        zoom2.removedOnCompletion = NO;
        zoom2.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
        zoom2.toValue = [NSValue valueWithCATransform3D:CATransform3DIdentity];
        [self.contentWrapper.layer addAnimation:zoom2 forKey:@"slowBeatPosition2"];

        CABasicAnimation* fadeInAndOut2 = [CABasicAnimation animationWithKeyPath:@"backgroundColor"];
        fadeInAndOut2.duration = 0.4f;
        fadeInAndOut2.speed = 1.0f;
        fadeInAndOut2.repeatCount = 1;
        fadeInAndOut2.fillMode = kCAFillModeForwards;
        fadeInAndOut2.removedOnCompletion = NO;
        fadeInAndOut2.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
        fadeInAndOut2.toValue = (id)[UIColor colorWithWhite:1.0f alpha:0.1f].CGColor;
        [self.redView.layer addAnimation:fadeInAndOut2 forKey:@"slowBeatColor2"];
        [CATransaction commit];
    });


}

顺利停止CABasicAnimation

1 个答案: