点击后退按钮时保存数据
我有一个简单的基于导航的应用程序，其中有一堆表单，我有一个连接到按钮的方法，该方法在点击按钮时保存数据，但我想知道当点击后退按钮时是否可以调用相同的方法导航？以防万一用户无法使用保存按钮。如果可以的话，我会怎样做呢？
提前致谢！
I have a simple navigation based app which has a bunch fo forms in it, I have a method connected to a button that saves data when the button is tapped but I was wondering if I could call the same method when the back button is tapped in the navigation? Just incase a user fails to use the save button. If it is possible, how would I go about it?
thanks in advance!
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当按下后退按钮时（但也在其他时候），您的视图控制器的
viewWillDisappear:方法将被调用，因此这可能是一个选项。但是，如果您呈现（例如）一个 modalViewController，或将另一个 viewController 推入导航堆栈，则也会调用
viewWillDisappear:。我能想到的唯一方法是
-dealloc方法，仅当控制器从导航堆栈中弹出时才会被调用。Your view controller's
viewWillDisappear:method will be invoked when the back button is pressed (but also at other times), so that might be an option.However,
viewWillDisappear:will also be invoked if you present (say) a modalViewController, or push another viewController onto the navigation stack.The only method I can think of that will be invoked only when the controller is popped from the navigation stack is the
-deallocmethod.当然，在 UIViewController 的
viewWillDisappear:方法中。Sure, in the
viewWillDisappear:method of the UIViewController.