UIPercentDrivenInteractiveTransition完成后会产生无关的动画

Question

我正在使用一个交互式自定义推送转换UIPercentDrivenInteractiveTransition.手势识别器成功调用交互控制器updateInteractiveTransition.同样,当我调用交互控制器时动画成功完成finishInteractiveTransition.

但是,有时我会在结尾处获得额外的一些分散注意力的动画(它似乎重复了动画的后半部分).有了相当简单的动画,我很少在iPhone 5上看到这种症状(虽然我在慢速笔记本电脑上工作时经常在模拟器上看到它).如果我使动画的计算成本更高(例如,大量阴影,多个视图为不同方向设置动画等),则设备上此问题的频率会增加.

有没有其他人看到这个问题,并找出一个解决方案,除了简化动画(我承认应该做的)和/或编写我自己的交互控制器？这种UIPercentDrivenInteractiveTransition方法有一定的优雅,但我对它不确定地行为不端的事实感到不安.别人看到过这种行为吗？有谁知道其他解决方案？

要说明效果,请参见下图.注意第二个场景,红色视图,当动画结束时,似乎第二次重复动画的后半部分.

此动画由以下内容生成:

• 反复呼叫updateInteractiveTransition,进度从0%升级到40%;

• 暂时停顿(因此您可以区分交互式过渡和完成动画finishInteractiveTransition);

• 然后调用finishInteractiveTransition完成动画; 和

• 动画控制动画的completion块调用completeTransition的transitionContext,以清理一切.

做一些诊断,似乎是最后一步触发了无关的动画.动画完成时会调用动画控制器的完成块,但是一旦我调用completeTransition它,它有时会重复动画的最后一位(特别是在使用复杂的动画时).

---

我不认为它是相关的,但这是我的配置导航控制器以执行交互式转换的代码:

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.navigationController.delegate = self;

    self.interationController = [[UIPercentDrivenInteractiveTransition alloc] init];
}

- (id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController
                                  animationControllerForOperation:(UINavigationControllerOperation)operation
                                               fromViewController:(UIViewController*)fromVC
                                                 toViewController:(UIViewController*)toVC
{
    if (operation == UINavigationControllerOperationPush)
        return [[PushAnimator alloc] init];

    return nil;
}

- (id <UIViewControllerInteractiveTransitioning>)navigationController:(UINavigationController*)navigationController
                          interactionControllerForAnimationController:(id <UIViewControllerAnimatedTransitioning>)animationController
{
    return self.interationController;
}

我PushAnimator是:

@implementation PushAnimator

- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext
{
    return 5.0;
}

- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
    UIViewController* toViewController   = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    UIViewController* fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];

    [[transitionContext containerView] addSubview:toViewController.view];
    toViewController.view.frame = CGRectOffset(fromViewController.view.frame, fromViewController.view.frame.size.width, 0);;

    [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
        toViewController.view.frame = fromViewController.view.frame;
    } completion:^(BOOL finished) {
        [transitionContext completeTransition:![transitionContext transitionWasCancelled]];
    }];
}

@end

注意,当我将调用语句放在我调用的地方时completeTransition,我可以看到这个无关的动画在我调用之后发生completeTransition(即使动画真的在那时完成).这表明额外的动画可能是调用的结果completeTransition.

仅供参考,我用手势识别器完成了这个实验:

- (void)handlePan:(UIScreenEdgePanGestureRecognizer *)gesture
{
    CGFloat width = gesture.view.frame.size.width;

    if (gesture.state == UIGestureRecognizerStateBegan) {
        [self performSegueWithIdentifier:@"pushToSecond" sender:self];
    } else if (gesture.state == UIGestureRecognizerStateChanged) {
        CGPoint translation = [gesture translationInView:gesture.view];
        [self.interactionController updateInteractiveTransition:ABS(translation.x / width)];
    } else if (gesture.state == UIGestureRecognizerStateEnded ||
               gesture.state == UIGestureRecognizerStateCancelled)
    {
        CGPoint translation = [gesture translationInView:gesture.view];
        CGPoint velocity    = [gesture velocityInView:gesture.view];
        CGFloat percent     = ABS(translation.x + velocity.x * 0.25 / width);

        if (percent < 0.5 || gesture.state == UIGestureRecognizerStateCancelled) {
            [self.interactionController cancelInteractiveTransition];
        } else {
            [self.interactionController finishInteractiveTransition];
        }
    }
}

我也通过调用updateInteractiveTransition和finishInteractiveTransition手动(从等式中消除手势识别器)来做到这一点,它仍然表现出这种奇怪的行为:

[self performSegueWithIdentifier:@"pushToSecond" sender:self];

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
    [self.interactionController updateInteractiveTransition:0.40];

    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        [self.interactionController finishInteractiveTransition];
    });
});

最后,我得出结论,这是一个UIPercentDrivenInteractiveTransition与复杂动画隔离的问题.我可以通过简化它们来最小化问题(例如,快照和动画快照视图).我还怀疑我可以通过不使用UIPercentDrivenInteractiveTransition和编写我自己的交互控制器来解决这个问题,它可以自动完成动画,而无需插入animationWithDuration块.

但我想知道是否有人想出任何其他技巧来使用UIPercentDrivenInteractiveTransition复杂的动画.

Answer 1

这个问题只出现在模拟器中.

解决方案:self.interactiveAnimator.completionSpeed = 0.999;

这里报告的错误:http://openradar.appspot.com/14675246

Answer 2

我见过类似的东西.我有两种可能的解决方法.一种是在动画完成处理程序中使用延迟性能:

} completion:^(BOOL finished) {
        double delayInSeconds = 0.1;
        dispatch_time_t popTime = 
             dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
        dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
            BOOL cancelled = [transitionContext transitionWasCancelled];
            [transitionContext completeTransition:!cancelled];
        });
       self.interacting = NO;
}];

另一种可能性是:不要使用百分比驱动动画!我自己手动驱动交互式自定义动画时从未遇到过这样的问题.