让viewDidAppear/viewWillAppear 在push/pop页面加载前始终调用

最新推荐文章于 2024-09-04 15:35:03 发布

原创最新推荐文章于 2024-09-04 15:35:03 发布 · 4.9k 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#uinavigationcontroller #methods #interface

技术文档同时被 3 个专栏收录

203 篇文章

订阅专栏

IOS框架知识

84 篇文章

订阅专栏

短代码（代码片段）

83 篇文章

订阅专栏

本文介绍了一种确保在iOS应用中，无论何时推入或弹出导航控制器堆栈上的视图控制器时，都能始终调用viewWillAppear/viewDidAppear方法的方法。通过实现UINavigationControllerDelegate协议并覆盖navigationController:willShowViewController:animated:与navigationController:didShowViewController:animated:方法，可以强制这些生命周期方法在控制器被推入或弹出时执行。

让viewDidAppear/viewWillAppear 在页面加载前始终调用

viewDidAppear/viewWillAppear in UINavigationController not be called

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 / viewDidAappear 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.