presentationLayer值在动画期间不更新？

Question

答案很可能是我不能按照我想要的方式混合东西,我会接受"正确的方法"来混合东西(可能是一个更复杂的CAAnimation？我不知道).是)我有的:

__block BOOL animationComplete = FALSE;
[[UIApplication sharedApplication] beginIgnoringInteractionEvents];
[UIView animateWithDuration:0.5f delay:0.0f options:UIViewAnimationCurveEaseInOut
    animations:^{
        [self setFrame:destRect];
    }
    completion:^(BOOL finished) {
        animationComplete = YES;
        [[UIApplication sharedApplication] endIgnoringInteractionEvents];
    }];

然后用以下方式对其进行轮询:

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, (unsigned long)NULL), ^{
    while (!animationComplete) {
        CALayer *layer = self.layer.presentationLayer;
        CGRect frame = [layer frame];
        CGPoint point = [layer position];
        float currentTranslation = [[layer valueForKeyPath:@"transform.translation.x"] floatValue];
        NSLog(@"%.1f : %.1f : %.1f : %.1f : %.1f : %.1f",frame.origin.x, currentTranslation, frame.origin.x, layer.bounds.origin.x, layer.position.x, point.x);
    }
});

我抓错了队列吗？错误的参数？我在看错了一层吗？以上是我试过看的值的散射,在动画期间都是不变的....

214.4 : 0.0 : 214.4 : 0.0 : 264.4 : 264.4
214.4 : 0.0 : 214.4 : 0.0 : 264.4 : 264.4
214.4 : 0.0 : 214.4 : 0.0 : 264.4 : 264.4
214.4 : 0.0 : 214.4 : 0.0 : 264.4 : 264.4
214.4 : 0.0 : 214.4 : 0.0 : 264.4 : 264.4

等:)

Answer 1

您只能与主线程上的视图层次结构进行交互.您不应该调用self.layer全局调度队列.你只能这样做dispatch_get_main_queue().

您必须将日志记录重写为不循环,因为完成块也在主线程上运行,并且如果块正在运行,它将无法运行.

UPDATE

问题肯定是从非主线程访问图层引起的.我用视图子类创建了一个测试项目MyView.我给了它这个方法:

- (IBAction)move {
    CGRect destRect = self.frame;
    destRect.origin.x = 300 - destRect.origin.x;

    __block BOOL animationComplete = FALSE;
    [[UIApplication sharedApplication] beginIgnoringInteractionEvents];
    [UIView animateWithDuration:0.5f delay:0.0f options:UIViewAnimationCurveEaseInOut
                     animations:^{
                         [self setFrame:destRect];
                     }
                     completion:^(BOOL finished) {
                         animationComplete = YES;
                         [[UIApplication sharedApplication] endIgnoringInteractionEvents];
                     }];

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, (unsigned long)NULL), ^{
        while (!animationComplete) {
            dispatch_sync(dispatch_get_main_queue(), ^{
                CALayer *layer = self.layer.presentationLayer;
                CGRect frame = [layer frame];
                CGPoint point = [layer position];
                float currentTranslation = [[layer valueForKeyPath:@"transform.translation.x"] floatValue];
                NSLog(@"%.1f : %.1f : %.1f : %.1f : %.1f : %.1f",frame.origin.x, currentTranslation, frame.origin.x, layer.bounds.origin.x, layer.position.x, point.x);
            });
        }
    });
}

当这个方法运行时,我输出如下:

2012-09-10 21:06:31.732 presentationLayerTest[1274:c07] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:06:31.735 presentationLayerTest[1274:c07] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:06:31.737 presentationLayerTest[1274:c07] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:06:31.737 presentationLayerTest[1274:c07] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:06:31.738 presentationLayerTest[1274:c07] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:06:31.739 presentationLayerTest[1274:c07] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:06:31.739 presentationLayerTest[1274:c07] 20.1 : 0.0 : 20.1 : 0.0 : 100.1 : 100.1
2012-09-10 21:06:31.740 presentationLayerTest[1274:c07] 20.1 : 0.0 : 20.1 : 0.0 : 100.1 : 100.1
2012-09-10 21:06:31.741 presentationLayerTest[1274:c07] 20.1 : 0.0 : 20.1 : 0.0 : 100.1 : 100.1
2012-09-10 21:06:31.741 presentationLayerTest[1274:c07] 20.1 : 0.0 : 20.1 : 0.0 : 100.1 : 100.1
2012-09-10 21:06:31.742 presentationLayerTest[1274:c07] 20.1 : 0.0 : 20.1 : 0.0 : 100.1 : 100.1
2012-09-10 21:06:31.743 presentationLayerTest[1274:c07] 20.1 : 0.0 : 20.1 : 0.0 : 100.1 : 100.1
2012-09-10 21:06:31.743 presentationLayerTest[1274:c07] 20.2 : 0.0 : 20.2 : 0.0 : 100.2 : 100.2
2012-09-10 21:06:31.744 presentationLayerTest[1274:c07] 20.2 : 0.0 : 20.2 : 0.0 : 100.2 : 100.2
2012-09-10 21:06:31.745 presentationLayerTest[1274:c07] 20.2 : 0.0 : 20.2 : 0.0 : 100.2 : 100.2
2012-09-10 21:06:31.745 presentationLayerTest[1274:c07] 20.2 : 0.0 : 20.2 : 0.0 : 100.2 : 100.2

...等等,X值最终达到280.

然后我注释掉了这一dispatch_sync行,所以层访问和日志记录发生在全局低优先级线程上,我输出如下:

2012-09-10 21:08:20.973 presentationLayerTest[1296:1b03] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:08:20.976 presentationLayerTest[1296:1b03] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:08:20.976 presentationLayerTest[1296:1b03] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:08:20.977 presentationLayerTest[1296:1b03] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:08:20.978 presentationLayerTest[1296:1b03] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:08:20.978 presentationLayerTest[1296:1b03] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:08:20.979 presentationLayerTest[1296:1b03] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:08:20.980 presentationLayerTest[1296:1b03] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:08:20.981 presentationLayerTest[1296:1b03] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:08:20.981 presentationLayerTest[1296:1b03] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:08:20.982 presentationLayerTest[1296:1b03] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:08:20.982 presentationLayerTest[1296:1b03] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:08:20.983 presentationLayerTest[1296:1b03] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0
2012-09-10 21:08:20.984 presentationLayerTest[1296:1b03] 20.0 : 0.0 : 20.0 : 0.0 : 100.0 : 100.0

...等等,X值永远不会改变.