UINavigationController and viewWillAppear / viewDidAppear

最新推荐文章于 2015-07-07 18:35:54 发布

转载最新推荐文章于 2015-07-07 18:35:54 发布 · 648 阅读

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#uinavigationcontroller #methods #interface

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本文介绍了如何通过将UINavigationControllerDelegate协议添加到根视图控制器来确保在导航控制器堆栈中推入或弹出视图控制器时，viewWillAppear和viewDidAppear方法总是被调用。

源自：http://www.idev101.com/code/User_Interface/UINavigationController/viewWillAppear.html

When you push or pop a view controller on/off a navigaction controller's stack, the usual viewWillAppear / viewDidAppear methods aren't called. If you want to ensure they're always called, just add the UINavigationControllerDelegate protocol to your root view controller:

@interface RootViewController : UIViewController <UINavigationControllerDelegate> {
    UINavigationController *navController;
}

Then implement these two methods:

- (void)navigationController:(UINavigationController *)navigationController 
    willShowViewController:(UIViewController *)viewController animated:(BOOL)animated 
{
    [viewController viewWillAppear:animated];
}

- (void)navigationController:(UINavigationController *)navigationController 
    didShowViewController:(UIViewController *)viewController animated:(BOOL)animated 
{
    [viewController viewDidAppear:animated];
}

Be sure to set the root view controller as the delegate for the nav controller. Now viewWillAppear / viewDidAppear will be called whenever a controller is pushed/popped from the stack.

If you want to call the viewWillDisappear/viewDidDisappear methods, your view controller still has to do that manually before popping itself off the nav stack.