iOS 7 UINavigationController 不平衡调用开始/结束外观转换

Question

我正在使用以下代码在 ViewDeck 中切换 View ，在 iOS5 和 6 中完全没问题，但在 iOS 7 中，当我尝试弹出到现有 View 时。屏幕变成全白/黑。

-(void)switchViewWithViewController:(UIViewController*)viewControllerToSwitch
{
    if (viewControllerToSwitch)
    {
        // Reset Menu Button
        [self.viewDeckController closeLeftViewAnimated:YES completion:^(IIViewDeckController *controller)
         {
             [((BaseViewController*)viewControllerToSwitch) closeMenu];
         }];

        @try
        {
            [((UINavigationController*)self.viewDeckController.centerController) pushViewController:viewControllerToSwitch animated:NO];
        }
        @catch (NSException * ex)
        {
            //“Pushing the same view controller instance more than once is not supported”
            NSRange range = [ex.reason rangeOfString:@"Pushing the same view controller instance more than once is not supported"];

            if([ex.name isEqualToString:@"NSInvalidArgumentException"] && range.location != NSNotFound)
            {
                //view controller already exists in the stack - just pop back to it
                if (!IS_IOS7)
                {
                    [((UINavigationController*)self.viewDeckController.centerController) popToViewController:viewControllerToSwitch animated:NO];
                }
                else
                {
                    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 0.1 * NSEC_PER_SEC), dispatch_get_main_queue(), ^(void)
                    {
                        [((UINavigationController*)self.viewDeckController.centerController) popToViewController:viewControllerToSwitch animated:NO];
                    });
                }
            }
        }
    }
}

我确实尝试添加延迟 0.1，但它没有帮助。 从控制台，我发现它同时弹出了两个 VC。

Unbalanced calls to begin/end appearance transitions for <GameViewController: 0x15ef5630>.
-[BaseViewController viewDidAppear:] [Line 49] VC is showing: GameViewController
-[BaseViewController viewDidAppear:] [Line 49] VC is showing: HomePageViewController

Answer 1

我承认使用 try 和 catch 不是一个好的做法。由于问题是关于 ViewDeck 的，所以我只是简单地即时替换 centerViewController，并避免 UINavigationController 的 push pop 堆栈错误。

这是代码。希望它可以帮助某人。

-(void)switchViewWithViewController:(BaseViewController*)viewControllerToSwitch
{
    if (viewControllerToSwitch)
    {
        // Reset Menu Button
        [self.viewDeckController closeLeftViewAnimated:YES completion:^(IIViewDeckController *controller)
         {
             [viewControllerToSwitch closeMenu];
         }];

        UINavigationController *navVC = [[UINavigationController alloc] initWithRootViewController:viewControllerToSwitch];
        self.viewDeckController.centerController = navVC;
    }
}