iOS：isMovingToParentViewController无法正常工作 [英] iOS: isMovingToParentViewController is not working as expected

问题描述

我的设置很简单，我的问题与这一个。然而，为了更好地解释它我在这里发布：

My setup is simple, and my issue is not very different from this one. However to better explain it I have posted it here:

NavController -> VC1 -> VC2

VC1是NavController的根视图控制器。
VC2可通过VC1的Push segue访问。

VC1 is root view controller of NavController. VC2 is accessible via Push segue from VC1.

我想在VC1中检测是否：

I want to detect, within VC1, whether:

它直接作为根视图控制器出现（通过Push）
它出现了VC2被弹出的结果

It appeared directly as root view controller (via Push) It appeared as a result of VC2 being popped

我读了下面应该说的文档告诉我以后是否属实。

I read the docs which says following should tell me if later is true.

isMovingToParentViewController == NO 

然而情况并非如此，以上情况总是证明是正确的。
这意味着，（self.isMovingToParentViewController == NO）总是在发生。

However that is not the case, and above condition ALWAYS turns out to be TRUE. Which means that, (self.isMovingToParentViewController == NO) is always happening.

这是我的代码：

- (void) viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    self.navigationController.navigationBarHidden = YES;

    //pushed to stack
    if (self.isMovingToParentViewController == YES)
    {
        //First time
      }
    else
    //popped off
    {
        //via Pop from VC2
    }    
}

同样是viewDidAppear的情况。

Same is the case for viewDidAppear, too.

事实上检查，我在开始时设置了断点，在以下两种情况下检查以下所有都是FALSE：

For a matter of fact check, I put breakpoint at the start, and checked that all of the following are FALSE, in both cases:

([self isMovingFromParentViewController])
([self isMovingToParentViewController])
([self isBeingPresented])
([self isBeingDismissed])

发生了什么事？
我的故事板里有什么东西可以搞定吗？
请帮忙...

What is happening? Is there anything I goofed up in my storyboard? Please help...

推荐答案

不幸的是，isMovingToParentViewController对于根视图控制器不是真的，所以我通常使用BOOL处理这种情况，

Unfortunately, isMovingToParentViewController isn't true for the root view controller, so I usually handle this situation with a BOOL,

@implementation ViewController {
    BOOL isFirstAppearance;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    isFirstAppearance = YES;
}

-(void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    if (isFirstAppearance) {
        NSLog(@"root view controller is moving to parent");
        isFirstAppearance = NO;
    }else{
        NSLog(@"root view controller, not moving to parent");
    }
}

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