我正在努力找到解決這個(gè)問(wèn)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(lái)確定是由于視圖控制器被推到導(dǎo)航控制器的堆棧上，還是因?yàn)橐晥D控制器因彈出而消失了。目前，我正在設(shè)置諸如的標(biāo)志，isShowingChildViewController但是它變得相當(dāng)復(fù)雜。我認(rèn)為我可以檢測(cè)到它的唯一方法是該-dealloc方法。
3 回答
慕標(biāo)琳琳
TA貢獻(xiàn)1830條經(jīng)驗(yàn) 獲得超9個(gè)贊
您可以使用以下內(nèi)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(dāng)然，這是可能的，因?yàn)樵谡{(diào)用viewWillDisappear時(shí)，UINavigationController的視圖控制器堆棧（通過(guò)viewControllers屬性公開）已經(jīng)更新。
大話西游666
TA貢獻(xiàn)1817條經(jīng)驗(yàn) 獲得超14個(gè)贊
我認(rèn)為最簡(jiǎn)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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