didMoveToParentViewController调用了两次

Question

我做了一个简单的测试,以了解更多有关包含视图控制器
我有一个视图控制器,我使用两个按钮的动作添加/删除了一个视图控制器:

- (IBAction)myInfoAddAction:(id)sender {
    profileViewController = [[ProfileViewController alloc] init];
    [self addChildViewController: profileViewController];
    UIView *__view = profileViewController.view;
    [self.view addSubview: __view];
    [profileViewController didMoveToParentViewController: self];
}

- (IBAction)myInfoRemoveAction:(id)sender {
    [profileViewController willMoveToParentViewController: nil];
    [profileViewController.view removeFromSuperview];
    [profileViewController removeFromParentViewController];
}

类ProfileViewController扩展UIViewController和覆盖willMoveToParentViewController以及didMoveToParentViewController方法

-( void)willMoveToParentViewController:(UIViewController *)parent
{
    [super willMoveToParentViewController: parent];
    NSLog(@"willMoveToParentViewController -> %@", self);
}

-( void) didMoveToParentViewController:(UIViewController *)parent
{
    [super didMoveToParentViewController: parent];
    NSLog(@"didMoveToParentViewController -> %@", self);
}

-( void)viewWillAppear:(BOOL)animated
{
    NSLog(@"viewWillAppear -> %@", self);
}

-( void)viewDidDisappear:(BOOL)animated
{
    NSLog(@"viewDidDisappear -> %@", self);
}

当我添加视图控制器时,我得到以下日志:

willMoveToParentViewController -> <ProfileViewController: 0x8c52ea0>
viewWillAppear -> <ProfileViewController: 0x8c52ea0>
didMoveToParentViewController -> <ProfileViewController: 0x8c52ea0>
didMoveToParentViewController -> <ProfileViewController: 0x8c52ea0>

当我删除视图控制器时:

willMoveToParentViewController -> <ProfileViewController: 0x8c52ea0>
didMoveToParentViewController -> <ProfileViewController: 0x8c52ea0>
viewDidDisappear -> <ProfileViewController: 0x8c52ea0>
didMoveToParentViewController -> <ProfileViewController: 0x8c52ea0>

我想知道为什么didMoveToParentViewController被调用两次？

谢谢!

Answer 1

我也有同样的问题.此外,我发现当我在viewDidLoad中添加子视图控制器时,我只有一条消息.我通过删除调用来修复它[super didMoveToParentViewController:].我认为这个问题与在按钮的回调中添加子视图控制器有关,但我不确定为什么这会导致问题.