我正在努力找到解決這個問題的好方法。在視圖控制器的-viewWillDisappear:方法中，我需要找到一種方法來確定是由于視圖控制器被推到導航控制器的堆棧上，還是因為視圖控制器因彈出而消失了。目前，我正在設置諸如的標志，isShowingChildViewController但是它變得相當復雜。我認為我可以檢測到它的唯一方法是該-dealloc方法。
3 回答
慕標琳琳
TA貢獻1830條經驗 獲得超9個贊
您可以使用以下內容。
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
NSArray *viewControllers = self.navigationController.viewControllers;
if (viewControllers.count > 1 && [viewControllers objectAtIndex:viewControllers.count-2] == self) {
// View is disappearing because a new view controller was pushed onto the stack
NSLog(@"New view controller was pushed");
} else if ([viewControllers indexOfObject:self] == NSNotFound) {
// View is disappearing because it was popped from the stack
NSLog(@"View controller was popped");
}
}
當然，這是可能的，因為在調用viewWillDisappear時，UINavigationController的視圖控制器堆棧（通過viewControllers屬性公開）已經更新。
大話西游666
TA貢獻1817條經驗 獲得超14個贊
我認為最簡單的方法是：
- (void)viewWillDisappear:(BOOL)animated
{
if ([self isMovingFromParentViewController])
{
NSLog(@"View controller was popped");
}
else
{
NSLog(@"New view controller was pushed");
}
[super viewWillDisappear:animated];
}
迅速：
override func viewWillDisappear(animated: Bool)
{
if isMovingFromParentViewController
{
print("View controller was popped")
}
else
{
print("New view controller was pushed")
}
super.viewWillDisappear(animated)
}
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