您是否熟悉viewWillAppear，viewDidAppear，viewDidLoad，viewWillDisappear和viewDidDisappear？

在此之前，让我问您viewWillAppear ， viewDidAppear ， viewDidLoad ， viewWillDisappear和viewDidDisappear的运行顺序是什么？

如果您知道答案，请关闭此网页并进行游戏。 🙂

因此，编写了一个简单的片段代码来验证这一点：

Example code:

Objective-C代码

适用于Swift爱好者的Swift代码

运行结果：

 2017-04-14 08:18:18.923 TestBlock[3940:264012] viewDidLoad is running 
 2017-04-14 08:18:18.924 TestBlock[3940:264012] viewWillAppear is running 
 2017-04-14 08:18:18.946 TestBlock[3940:264012] viewDidAppear is running 
 2017-04-14 08:18:22.187 TestBlock[3940:264012] viewWillDisappear is running 
 2017-04-14 08:18:22.689 TestBlock[3940:264012] viewDidDisappear is running 

单击按钮后，您将看到顺序：

1. viewDidLoad
2. viewWillAppear
3. viewDidAppear
4. viewWillDisappear
5. viewDidDisappear