BCTabBarController 中未调用 viewWillAppear

Question

我有一个大型项目，客户希望自定义标签栏。我选择 BCTabBarController 来替换 UITabbarController。经过几次修复后，它工作正常，但经过测试，我发现了一个错误：

ViewWillAppear, ViewDidAppear, ViewWillDisappear ViewDidDisappear methods not called in selectded view controller and not called into BCTabBarController.
This problem appears after BCTabBarController show modal controller from instance of BCTabBarController class.

我已 将问题发布到 github 存储库< /a> 的 briancolins，但仍然没有答案。

这里是我调用当前模态视图控制器的一些代码：

    - (void) presentProperlyModalViewController:(UIViewController *)modalViewController animated:(BOOL)animated
{
    if ([[self controllerToPresentModalFrom] respondsToSelector:@selector(presentViewController:animated:completion:)]) // For iOS 5
    {
        [[self controllerToPresentModalFrom] presentViewController:modalViewController animated:animated completion:^(){}];
    }
    else
    {
        [[self controllerToPresentModalFrom] presentModalViewController:modalViewController animated:animated];
    }
}

-(void) dismissProperlyModalViewControllerAnimated:(BOOL)animated
{
    if ([self respondsToSelector:@selector(dismissViewControllerAnimated:completion:)]) {
        [self dismissViewControllerAnimated:animated completion:^(){}];
    }
    else
    {
        [self dismissModalViewControllerAnimated:YES];
    }
}

更新：此问题未在 iOS5 中重现，但出现在 iOS 4.3 中

Answer 1

正如你所指出的。 iOS 5 会转发消息，而之前的版本则不会。以下是我处理类似情况的方法：

- (BOOL)needsMessageForwarding:(UIViewController *)vc {
    if ( [vc isKindOfClass:[UINavigationController class]] == NO)
        return YES;

    NSString *ver = [UIDevice currentDevice].systemVersion;
    if ( [ver characterAtIndex:0 < '5'] )
        return YES;

    return NO;
}

- (void) viewWillAppear:(BOOL)animated {
    ...
    if ( [self needsMessageForwarding:modalViewController] )
        [modalViewController viewWillAppear:animated];
    ...
}

// repeat pattern in the other viewWill... viewDid... functions.

在我的情况下，我有一个可能可见的视图控制器列表，因此我管理哪个视图控制器可见并将消息转发给它。