ios控制器生存周期

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• iOS中控制器的生命週期

　　一般我們在建立控制器的時候，有三種方法。

　　1.  直接通過代碼建立

　　2.  通過storyboard建立

　　3.  通過Xib，在建立控制器的時候傳入一個Xib檔案作為這個控制器的view。

 

• 直接通過代碼建立

　　通過代碼建立這種凡是，我們列印調用順序可以發現

　　

　　對應的代碼調用順序就是  loadView -> viewDidLoad -> viewWillAppear -> viewWillLayoutSubviews -> viewDidLayoutSubviews -> viewDidAppear

　　

// 1. - (void)loadView; // This is where subclasses should create their custom view hierarchy if they aren‘t using a nib. Should never be called directly.// 2.- (void)viewDidLoad; // Called after the view has been loaded. For view controllers created in code, this is after -loadView. For view controllers unarchived from a nib, this is after the view is set.// 3.- (void)viewWillAppear:(BOOL)animated;    // Called when the view is about to made visible. Default does nothing// 4.- (void)viewWillLayoutSubviews NS_AVAILABLE_IOS(5_0);// Called just after the view controller‘s view‘s layoutSubviews method is invoked. Subclasses can implement as necessary. The default is a nop.// 5.- (void)viewDidLayoutSubviews NS_AVAILABLE_IOS(5_0);

　　控制器建立之後，彈出另一個控制器(當前控制器消失)，執行的代碼順序 viewWillDisappear -> viewWillLayoutSubviews -> viewDidLayoutSubviews -> viewDidDisappear

　　

　　

// 1.- (void)viewWillDisappear:(BOOL)animated; // Called when the view is dismissed, covered or otherwise hidden. Default does nothing// 2.- (void)viewWillLayoutSubviews NS_AVAILABLE_IOS(5_0);// Called just after the view controller‘s view‘s layoutSubviews method is invoked. Subclasses can implement as necessary. The default is a nop.// 3.- (void)viewDidLayoutSubviews NS_AVAILABLE_IOS(5_0);// 4.- (void)viewDidDisappear:(BOOL)animated;  // Called after the view was dismissed, covered or otherwise hidden. Default does nothing

 

• 通過storyboard建立控制器

　　

UIStoryboard *storyBoard = [UIStoryboard storyboardWithName:NSStringFromClass([CViewController class]) bundle:nil];CViewController *touch = [storyBoard instantiateViewControllerWithIdentifier:NSStringFromClass([CViewController class])];[self presentViewController:touch animated:YES completion:nil];

　　為了方便，同時減少手誤，這裡重用ID我們使用類名

　　 

　　通過列印來觀察

　　

　　可以看到代碼的調用順序就是 awakeFromNib -> loadView -> viewWillAppear -> viewWillLayoutSubviews -> viewDidLayoutSubviews -> viewDidAppear

// 1.- (void)awakeFromNib NS_REQUIRES_SUPER;// 2.- (void)loadView; // This is where subclasses should create their custom view hierarchy if they aren‘t using a nib. Should never be called directly.// 3.- (void)viewDidLoad; // Called after the view has been loaded. For view controllers created in code, this is after -loadView. For view controllers unarchived from a nib, this is after the view is set.// 4.- (void)viewWillAppear:(BOOL)animated;    // Called when the view is about to made visible. Default does nothing// 5.- (void)viewWillLayoutSubviews NS_AVAILABLE_IOS(5_0);// Called just after the view controller‘s view‘s layoutSubviews method is invoked. Subclasses can implement as necessary. The default is a nop.- (void)viewDidLayoutSubviews NS_AVAILABLE_IOS(5_0);// 6.- (void)viewDidAppear:(BOOL)animated;     // Called when the view has been fully transitioned onto the screen. Default does nothing

　　這裡需要注意的是，我們是控制器通過storyboard來載入，那麼是根據storyboard的描述建立view。

　　

• 通過XIB來建立載入控制器

　　首先建立一個XIB，快速鍵 command + N 來建立。

　　

　　

　　建立後XIB之後我們還需要設定檔案

　　

這裡設定為我們建立的控制器

　　

　　所有需要的已經設定好，這時候我們可以來碼代碼了。

DViewController *touch = [[DViewController alloc] initWithNibName:NSStringFromClass([DViewController class]) bundle:nil];[self presentViewController:touch animated:YES completion:nil];

　　下面我們來觀察控制器的生命週期

　　代碼層面上就是

// 1.- (void)loadView; // This is where subclasses should create their custom view hierarchy if they aren‘t using a nib. Should never be called directly.// 2.- (void)viewDidLoad; // Called after the view has been loaded. For view controllers created in code, this is after -loadView. For view controllers unarchived from a nib, this is after the view is set.// 3.- (void)viewWillAppear:(BOOL)animated;    // Called when the view is about to made visible. Default does nothing// 4.可能會多次調用- (void)viewWillLayoutSubviews NS_AVAILABLE_IOS(5_0);// Called just after the view controller‘s view‘s layoutSubviews method is invoked. Subclasses can implement as necessary. The default is a nop.- (void)viewDidLayoutSubviews NS_AVAILABLE_IOS(5_0);// 5.- (void)viewDidAppear:(BOOL)animated;     // Called when the view has been fully transitioned onto the screen. Default does nothing

　　說明：

　　載入XIB的時候，我們同樣可以不指定XIB名稱，這樣loadView 就會最終載入與控制器同名的 XIB （命名規範很重要啊）

DViewController *touch = [[DViewController alloc] init];[self presentViewController:touch animated:YES completion:nil];

　　同時，如果我們刪掉 DViewController.xib ,同時建立一個 DView.xib 當我們用以上不指定xib名稱，同樣是可以載入出來的（命名規範很重要）。

　　我們可以知道，載入xib的過程是，如果指定名稱，那麼載入指定名稱的xib，如果沒有指定名稱就會載入和控制器同名的xib，如果沒有就會找去控制器名相同但是沒有 controller 的xib來載入。

 

• A present B控制器再返回，兩個控制器的生命週期

　　1. 建立A控制器

　　

　　流程：

A:loadViewA:viewDidLoadA:viewWillAppearA:viewWillLayout...A:viewDidAppear

　　2. A present 到B控制器

　　

　　流程：

A:loadViewA:viewDidLoadA:viewWillAppearA:viewWillLayout...    // 可能多次調用A:viewDidAppear-------------- Present B控制器 --------------B:loadViewB:viewDidLoadA:viewWillDisappearB:viewWillAppearB:viewLayout....   // 可能多次調用A;viewLayout...   // 可能多次調用B:viewDidAppear   // 多次調用，會跟下面的調用順序可能會有些調換A:viewDidDisappear

 

ios控制器生存周期