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//添加
[self addChildViewController:newVC]; //[newVC willMoveToParentViewController:self]; [self.view addSubview:newVC.view]; [newVC didMoveToParentViewController:self];
//删除 [oldVC willMoveToParentViewController:nil]; [oldVC.view removeFromSuperview]; [oldVC removeFromParentViewController]; //[oldVC didMoveToParentViewController:nil];
// 方法 addChildViewController: removeFromParentViewController:
transitionFromViewController:toViewController:duration:options:animations:completion: willMoveToParentViewController: didMoveToParentViewController: // 属性 @property(nonatomic,readonly) NSArray *childViewControllers
上?面代码中写出了添加和移除ChildViewController的具体写法,添加过程:
1. 通过addChildViewController:添加?子控制器
2. 这一步为隐式调?用,系统在addChildViewController:?方法后会?自动调?用方法willMoveToParentViewController:
3. 将?子控制器视图添加进主视图
4. 通知?子控制器childViewController添加完成,这一步需要手动显示调用
移除过程与之相反,只是调用的几个方法名不?样。
在Apple官?方?文档上明确表?了必须要调?用didMoveToParentViewController和
willMoveToParentViewController?法来确认完成过程执?行完毕,初学者需要特别注意和?个方法的调?用顺序,使?用不当会导UIViewControllerHierarchyInconsistency的警告。
介绍了使?用?法,在来介绍一下使?用它的好处,好处就是规避了上面提到的两种误用产生的后果,具体就是:
1. 解决了代码的?高耦合
2. 系统在收到内存警告的时候会回收?一些并未显?示的view,释放内存
3. 这种?方式add进入的view是属于当前view hierarchy内,可以正常传递各种事件。
//在parent view controller 中添加 child view controller FirstViewController *firstViewController=[[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil]; [self addChildViewController:firstViewController]; SecondViewController *secondViewController=[[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil]; [self addChildViewController:secondViewController]; ThirdViewController *thirdViewController=[[ThirdViewController alloc] initWithNibName:@"ThirdViewController" bundle:nil]; [self addChildViewController:thirdViewController]; [self.view addSubview:thirdViewController.view]; // addChildViewController回调用[child willMoveToParentViewController:self] ,但是不会调用didMoveToParentViewController,所以需要显示调用 [thirdViewController didMoveToParentViewController:self]; currentViewController=thirdViewController; //切换child view controller [self transitionFromViewController:currentViewController toViewController:firstViewController duration:4 options:UIViewAnimationOptionTransitionFlipFromLeft animations:^{ } completion:^(BOOL finished) { //...... }]; currentViewController=firstViewController; //移除child view controller // removeFromParentViewController在移除child前不会调用[self willMoveToParentViewController:nil] ,所以需要显示调用 [currentViewController willMoveToParentViewController:nil]; [currentViewController.view removeFromSuperview]; [currentViewController removeFromParentViewController];
// // HMTMainViewController.m // UIScrollView // // Created by HMT on 14-6-25. // Copyright (c) 2014年 humingtao. All rights reserved. // #import "HMTMainViewController.h" #import "HMTFirstViewController.h" #import "HMTSecondViewController.h" #import "HMTThirdViewController.h" @interface HMTMainViewController () <UIScrollViewDelegate> @property (nonatomic ,strong) HMTThirdViewController *thirdVC; @property (nonatomic ,strong) HMTFirstViewController *firstVC; @property (nonatomic ,strong) HMTSecondViewController *secondVC; @property (nonatomic ,strong) UIViewController *currentVC; @property (nonatomic ,strong) UIScrollView *headScrollView; // 顶部滚动视图 @property (nonatomic ,strong) NSArray *headArray; @end @implementation HMTMainViewController - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil { self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; if (self) { // Custom initialization } return self; } - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view. self.navigationItem.title = @"网易新闻Demo"; self.headArray = @[@"头条",@"娱乐",@"体育",@"财经",@"科技",@"NBA",@"手机"]; /** * automaticallyAdjustsScrollViewInsets 又被这个属性坑了 * 我"UI高级"里面一篇文章着重讲了它,大家可以去看看 */ self.automaticallyAdjustsScrollViewInsets = NO; self.headScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 64, 320, 40)]; self.headScrollView.backgroundColor = [UIColor purpleColor]; self.headScrollView.contentSize = CGSizeMake(560, 0); self.headScrollView.bounces = NO; self.headScrollView.pagingEnabled = YES; [self.view addSubview:self.headScrollView]; for (int i = 0; i < [self.headArray count]; i++) { UIButton *button = [UIButton buttonWithType:UIButtonTypeSystem]; button.frame = CGRectMake(0 + i*80, 0, 80, 40); [button setTitle:[self.headArray objectAtIndex:i] forState:UIControlStateNormal]; button.tag = i + 100; [button addTarget:self action:@selector(didClickHeadButtonAction:) forControlEvents:UIControlEventTouchUpInside]; [self.headScrollView addSubview:button]; } /* 苹果新的API增加了addChildViewController方法,并且希望我们在使用addSubview时,同时调用[self addChildViewController:child]方法将sub view对应的viewController也加到当前ViewController的管理中。 对于那些当前暂时不需要显示的subview,只通过addChildViewController把subViewController加进去;需要显示时再调用transitionFromViewController方法。将其添加进入底层的ViewController中。 这样做的好处: 1.无疑,对页面中的逻辑更加分明了。相应的View对应相应的ViewController。 2.当某个子View没有显示时,将不会被Load,减少了内存的使用。 3.当内存紧张时,没有Load的View将被首先释放,优化了程序的内存释放机制。 */ /** * 在iOS5中,ViewController中新添加了下面几个方法: * addChildViewController: * removeFromParentViewController * transitionFromViewController:toViewController:duration:options:animations:completion: * willMoveToParentViewController: * didMoveToParentViewController: */ self.firstVC = [[HMTFirstViewController alloc] init]; [self.firstVC.view setFrame:CGRectMake(0, 104, 320, 464)]; [self addChildViewController:_firstVC]; self.secondVC = [[HMTSecondViewController alloc] init]; [self.secondVC.view setFrame:CGRectMake(0, 104, 320, 464)]; self.thirdVC = [[HMTThirdViewController alloc] init]; [self.thirdVC.view setFrame:CGRectMake(0, 104, 320, 464)]; // 默认,第一个视图(你会发现,全程就这一个用了addSubview) [self.view addSubview:self.firstVC.view]; self.currentVC = self.firstVC; } - (void)didClickHeadButtonAction:(UIButton *)button { // 点击处于当前页面的按钮,直接跳出 if ((self.currentVC == self.firstVC && button.tag == 100)||(self.currentVC == self.secondVC && button.tag == 101.)) { return; }else{ // 展示2个,其余一样,自行补全噢 switch (button.tag) { case 100: [self replaceController:self.currentVC newController:self.firstVC]; break; case 101: [self replaceController:self.currentVC newController:self.secondVC]; break; case 102: //....... break; case 103: //....... break; case 104: //....... break; case 105: //....... break; case 106: //....... break; //....... default: break; } } } // 切换各个标签内容 - (void)replaceController:(UIViewController *)oldController newController:(UIViewController *)newController { /** * 着重介绍一下它 * transitionFromViewController:toViewController:duration:options:animations:completion: * fromViewController 当前显示在父视图控制器中的子视图控制器 * toViewController 将要显示的姿势图控制器 * duration 动画时间(这个属性,old friend 了 O(∩_∩)O) * options 动画效果(渐变,从下往上等等,具体查看API) * animations 转换过程中得动画 * completion 转换完成 */ [self addChildViewController:newController]; [self transitionFromViewController:oldController toViewController:newController duration:2.0 options:UIViewAnimationOptionTransitionCrossDissolve animations:nil completion:^(BOOL finished) { if (finished) { [newController didMoveToParentViewController:self]; [oldController willMoveToParentViewController:nil]; [oldController removeFromParentViewController]; self.currentVC = newController; }else{ self.currentVC = oldController; } }]; }
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原文地址:http://www.cnblogs.com/coderMJL/p/5058488.html