完成转换时的io7导航检查

Question

我想标记我UINavigationController的动画(推/弹)或不是.

我有一个BOOL变量(_isAnimating),下面的代码似乎工作:

- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    _isAnimating = YES;
}

- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    _isAnimating = NO;
}

但它在iOS7中使用滑动手势无法正常工作.假设我的导航是:root-> view A - > view B. 我现在在B.

• 在滑动开始时(从B回到A)navigationController:willShowViewController:animated:(BOOL)animated,然后调用函数" " _isAnimating = YES.

• 正常情况是滑动完成(返回A)navigationController:didShowViewController:animated:(BOOL)animated,然后调用函数" " _isAnimating = NO.这种情况没问题,但是:

• 如果用户可能只刷一半(半转换到A),然后不想滑动到上一个视图(视图A),他再次转到当前视图(再次保持B).然后navigationController:didShowViewController:animated:(BOOL)animated没有调用函数" ",我的变量值不正确(_isAnimating=YES).

在这种异常情况下,我没有机会更新我的变量.有没有办法更新导航状态？谢谢!

Answer 1

解决问题的线索可以在UINavigationController的InteractivePopGestureRecognizer属性中找到。这是通过滑动手势响应弹出控制器的识别器。您可以注意到，当用户抬起手指时，识别器的状态更改为UIGestureRecognizerStateEnded 。因此，除了导航控制器委托之外，您还应该将目标添加到流行识别器：

UIGestureRecognizer *popRecognizer = self.navigationController.interactivePopGestureRecognizer;
[popRecognizer addTarget:self                       
                  action:@selector(navigationControllerPopGestureRecognizerAction:)];

每次 Pop 识别器更改时（包括手势结束）都会调用此操作。

- (void)navigationControllerPopGestureRecognizerAction:(UIGestureRecognizer *)sender
{
    switch (sender.state)
    {
        case UIGestureRecognizerStateEnded:

        // Next cases are added for relaibility
        case UIGestureRecognizerStateCancelled:
        case UIGestureRecognizerStateFailed:

            _isAnimating = NO;
            break;

        default:
            break;
    }
}

PS 不要忘记该interactivePopGestureRecognizer属性自 iOS 7 起就可用！