qq_41423782的博客

方法执行顺序为：init -> viewDidLoad -> viewWillAppear -> viewDidAppear viewDidLoad是当程序第一次加载view时调用，以后都不会用到，而viewDidAppear是每当切换到view时就调用。 viewDidLoad Called after the view has been loaded. For view controllers created in code, this is after -loadView. For