UIViewController之［自定义容器视图控制器］

1.简介

Container的主要职责就是管理一个或多个Child View Controller的展现的生命周期，须要传递显示以及旋转相关的回调

一个app首先有一个主window，window指定一个rootViewController

window会将相关的回调传递给rootViewController

rootViewController须要再将这些callbacks的调用传递给它的Child View Controllers

显示相关的回调：appearance callbacks(
          viewWillAppear:
          viewWillDisappear:
          viewDidAppear:
          viewDidDisappear: 
)
旋转相关的回调：rotation callbacks(
          willRotateToInterfaceOrientation:duration: 
          willAnimateRotationToInterfaceOrientation:duration:,
          didRotateFromInterfaceOrientation:
)

2.父子关系（parentViewController－－subViewController）

实现一个Custom Container View Controller分为两个阶段

①父子关系的创建

②️父子关系的解除

2.1创建父子关系

//将subViewController添加为child view controller，addChildViewController:接口创建了逻辑上的父子关系
    //子能够经过parentViewController，访问其父VC
    //addChildViewController:接口的逻辑中会自动调用 [subViewController willMoveToParentViewController : parentViewController]; 
    [parentViewController addChildViewController : subViewController];

    //创建父子关系后，即是将content的view加入到父VC的view hierarchy(层次结构)上
    [parentViewController.view addSubview : subViewController.view];

    //调用child的 didMoveToParentViewController: ，以通知child，完成了父子关系的创建
    [subViewController didMoveToParentViewController : parentViewController];

2.2解除父子关系

//通知child，即将解除父子关系
    [self willMoveToParentViewController:nil];

    //将child的view从父VC的view的hierarchy中移除
    [self.view removeFromSuperview];

    //经过removeFromParentViewController的调用真正的解除关系
    //removeFromParentViewController会自动调用 [content didMoveToParentViewController:nil]
    [self removeFromParentViewController];

3. appearance callbacks的传递

生命周期：

alloc -> initWithNibName -> loadView -> viewDidLoad -> viewWillAppear -> viewDidAppear -> viewWillDisappear -> viewDidDisappear -> dealloc

其实，callbacks系统会自动调用，可是有些需求自动调用不能知足需求，如：

child view的展现有一个动画的过程，这个时候咱们并不想viewDidAppear的调用在addSubview的时候进行，而是等展现动画结束后再调用viewDidAppear。

自定义容器中须要关闭自动调用callbacks，本身去控制callbacks的调用时机

3.1如何关闭自动传递：

IOS5: automaticallyForwardAppearanceAndRotationMethodsToChildViewControllers
        return NO；
    IOS6+：shouldAutomaticallyForwardAppearanceMethods
        return NO；

3.2手动传递

手动传递须要用到一下两个方法， 并且必须成对出现

beginAppearanceTransition:animated:

endAppearanceTransition

//触发subViewController的viewWillAppear
    [subViewController beginAppearanceTransition:YES animated:animated];           
    
    //触发subViewController的viewWillDisappear
    [subViewController beginAppearanceTransition:NO animated:animated];

    //触发对应的viewDidAppear和viewDidDisappear
    [subViewController endAppearanceTransition];

例子

/**
*将subViewController添加入parentViewController中
*调用该方法后，能够添加子控制器显示时的动画效果
*/
-(void)addToParentViewContoller:(UIViewController *)parentViewController subViewController:(UIViewController*)subViewController{
    [subViewController beginAppearanceTransition:YES animated:animated]; 

    [parentViewController addChildViewController : subViewController];
    [parentViewController.view addSubview : subViewController.view];
    [subViewController didMoveToParentViewController : parentViewController];

    [subViewController endAppearanceTransition];     
}

/**
* 将subViewController从parentViewController中删除
*/
-(void)removeFromParentViewContoller:(UIViewController *)parentViewController subViewController:(UIViewController*)subViewController{
    [subViewController beginAppearanceTransition:NO animated:animated]; 

    [subViewController willMoveToParentViewController:nil];
    [subViewController.view removeFromSuperview];
    [subViewController removeFromParentViewController];

    [subViewController endAppearanceTransition];     
}

4. rotation callbacks的传递

转屏时才会须要关注的问题

4.1如何关闭自动传递：

IOS5: automaticallyForwardAppearanceAndRotationMethodsToChildViewControllers
        return NO；
    IOS6+：shouldAutomaticallyForwardRotationMethods
        return NO；

转屏时触发的函数：请参照以下连接：

转屏时触发函数 http://my.oschina.net/u/2462423/blog/523235#OSC_h3_6

更多详细内容请参照以下连接：

更多详细内容 http://www.cocoachina.com/industry/20140523/8528.html