xcode 在导航控制器中单击后退按钮时调用哪个方法？
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Which method is called when back button clicked in navigation controller?
提问by ???
I want to save DB when the back button clicked in navigation controller.
我想在导航控制器中单击后退按钮时保存数据库。
so I would insert code in method.
所以我会在方法中插入代码。
What method is called when back button clicked in navigation controller?
在导航控制器中单击后退按钮时调用什么方法？
采纳答案by Benjie
To do what you asked, look at the UINavigationControllerDelegateprotocol, namely the method:
做你问的，看UINavigationControllerDelegate协议，即方法：
- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
when the viewController argument is no longer your view controller then you should save.
当 viewController 参数不再是您的视图控制器时，您应该保存。
However, doing so on viewWillDisappear:might be a better (and much simpler) idea.
然而，这样做viewWillDisappear:可能是一个更好（也更简单）的想法。
回答by Vladimir Stazhilov
Maybe it's not appropriate use, but that worked for me. Don't forget to set UINavaigationController delegate.
也许它不适合使用，但这对我有用。不要忘记设置 UINavaigationController 委托。
- (id <UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController
animationControllerForOperation:(UINavigationControllerOperation)operation
fromViewController:(UIViewController *)fromVC
toViewController:(UIViewController *)toVC
{
NSLog(@"from VC class %@", [fromVC class]);
if ([fromVC isKindOfClass:[ControllerYouJustPopped class]])
{
NSLog(@"Returning from popped controller");
}
return nil;
}
