将子视图控制器添加到 UINavigationController

Question

我正在尝试使用以下代码将子视图控制器添加到包含在 UINavigationController 中的 UIViewController：

- (void)buttonTapped:(id)sender
{
    MyChildController *viewController = [self.storyboard instantiateViewControllerWithIdentifier:@"MyChild"];
    [self addChildViewController:viewController];
    [self.view addSubview:viewController.view];
    [viewController didMoveToParentViewController:self];


    viewController.view.alpha = 0.0f;
    [UIView animateWithDuration:0.4 animations:^{
        viewController.view.alpha = 1.0f;
    }];
}

但结果是这样的：

如您所见，UINavigatioBar 和 UIToolbar 仍位于子视图控制器的顶部。我怎样才能把子视图控制器放在首位？我已经尝试将代码替换为：

[self.navigationController addChildViewController:viewController];
    [self.navigationController.view addSubview:viewController.view];
    [viewController didMoveToParentViewController:self.navigationController];

但是这样viewController 的viewDidAppear:animated 就不会被调用。我不知道，为什么。

Answer 1

@Pwner的回答 Swift 版：

将子元素添加到 UINavigaitonController

let child = MyChildViewController()
self.navigationController?.addChildViewController(child)
guard let navigationController = navigationController else {
    return
}
child.view.frame = navigationController.view.bounds
child.beginAppearanceTransition(true, animated: true)
self.navigationController?.view.addSubview(child.view)
self.view.alpha = 0
UIView.animate(withDuration: 0.3, animations: {
    child.view.alpha = 1.0
}, completion: { _ in
    guard let navigationController = self.navigationController else {
        return
    }
    child.endAppearanceTransition()
    child.didMove(toParentViewController: navigationController)
})

从 UINavigationController 中移除一个子节点

child.willMove(toParentViewController: nil)
child.beginAppearanceTransition(false, animated: true)
UIView.animate(withDuration: 0.3, animations: {
    child.view.alpha = 0.0
}, completion: { _ in
    guard let navigationController = self.navigationController else {
        return
    }
    child.view.removeFromSuperview()
    child.endAppearanceTransition()
    child.removeFromParentViewController()
})

Answer 2

@Sam 的评论是正确的。您需要调用beginApperanceTransition:animated: 和endAppearanceTransition 以触发viewDidAppear。 UINavigationController在添加子视图控制器时不调用viewDidAppear的原因是因为它已经覆盖了它的容器组合方法，以防止程序员在奇怪的地方添加子视图控制器。在您的情况下，它不希望您的子视图覆盖导航栏。导航控制器的正确用法是让孩子出现在导航栏下方。尽管如此，您仍然可以通过手动告诉孩子它何时出现以及何时结束来强制使用这种非标准 UI。

向 UINavigationController 添加一个子节点

MyChildViewController* child = [[MyChildViewController alloc] init];
[self.navigationController addChildViewController:child];
child.view.frame = self.navigationController.view.bounds;
[self.navigationController.view addSubview:child.view];
child.view.alpha = 0.0;
[child beginAppearanceTransition:YES animated:YES];
[UIView
    animateWithDuration:0.3
    delay:0.0
    options:UIViewAnimationOptionCurveEaseOut
    animations:^(void){
        child.view.alpha = 1.0;
    }
    completion:^(BOOL finished) {
        [child endAppearanceTransition];
        [child didMoveToParentViewController:self.navigationController];
    }
];

从 UINavigationController 中移除一个孩子

[child willMoveToParentViewController:nil];
[child beginAppearanceTransition:NO animated:YES];
[UIView
    animateWithDuration:0.3
    delay:0.0
     options:UIViewAnimationOptionCurveEaseOut
    animations:^(void){
        child.view.alpha = 0.0;
    }
    completion:^(BOOL finished) {
        [child endAppearanceTransition];
        [child.view removeFromSuperview];
        [child removeFromParentViewController];
    }
];

Answer 3

在您的第一个视图控制器中，执行以下操作：

- (IBAction)buttonClick:(id)sender
{
    SecondViewController *secondView = [self.storyboard instantiateViewControllerWithIdentifier:@"SecondViewController"];
    UIImage *blurryImage = [UIImage imageNamed:@"foo.jpeg"];
    secondView.imageView.image = blurryImage;
    [self.navigationController addChildViewController:secondView];
    secondView.view.frame = self.navigationController.view.frame;
    [self.navigationController.view addSubview:secondView.view];
}

然后在您的第二个视图控制器中，为您的 imageview 添加 getter：

-(UIImageView *)imageView
{
    if( _imageView == nil )
    {
        _imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 320, 548)];
        [self.view addSubview:_imageView];
    }
    return _imageView;
}