iOS5中 UIViewController新方法的使用

 

From: http://www.cocoachina.com/newbie/basic/2012/0112/3870.html

 

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:

下面详细介绍一下addChildViewController，一个ViewController可以添加多个子ViewController， 但是这些子ViewController只有一个是显示到父视图中的，可以通过 transitionFromViewController:toViewController:duration:options:animations:completion: 这个方法转换显示的子视图。同时加入相应的动画。下面以一个例子来说明，最后实现的效果：

 

下面详细介绍一下上述效果的实现：

创建项目，changeViewController。
添加相应的viewController，MainViewController、FirstViewController、SecondViewController、ThirdViewController。如下图：

3.把MainViewController添加到window中。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
MainViewController *mainViewController=[[MainViewController alloc] initWithNibName:@"MainViewController" bundle:nil];
self.window.rootViewController=mainViewController;
[self.window makeKeyAndVisible];
return YES;
}

4.在MainViewController中添加三个按钮，并且连接onClickbutton方法。

5.在MainViewController中添加三个子controller

#pragma mark – View lifecycle

- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.

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];

[contentView addSubview:thirdViewController.view];

currentViewController=thirdViewController;

}

其中要把其中的一个子controller的view添加到根视图中，这样才能显示出相应的视图。

6.点击按钮，切换视图。

-(IBAction)onClickbutton:(id)sender
{
FirstViewController *firstViewController=[self.childViewControllers objectAtIndex:0];
ThirdViewController *thirdViewController=[self.childViewControllers objectAtIndex:2];
SecondViewController *secondViewController=[self.childViewControllers objectAtIndex:1];
if ((currentViewController==firstViewController&&[sender tag]==1)||(currentViewController==secondViewController&&[sender tag]==2) ||(currentViewController==thirdViewController&&[sender tag]==3) ) {
return;
}
UIViewController *oldViewController=currentViewController;
switch ([sender tag]) {
case 1:
{
NSLog(@"留言及回复");
[self transitionFromViewController:currentViewController toViewController:firstViewController duration:4 options:UIViewAnimationOptionTransitionFlipFromLeft animations:^{
} completion:^(BOOL finished) {
if (finished) {
currentViewController=firstViewController;
}else{
currentViewController=oldViewController;
}
}];
}
break;
case 2:
{
NSLog(@"生日提醒");
[self transitionFromViewController:currentViewController toViewController:secondViewController duration:1 options:UIViewAnimationOptionTransitionFlipFromTop animations:^{

} completion:^(BOOL finished) {
if (finished) {
currentViewController=secondViewController;
}else{
currentViewController=oldViewController;
}
}];
}
break;
case 3:
{
NSLog(@"好友申请");
[self transitionFromViewController:currentViewController toViewController:thirdViewController duration:1 options:UIViewAnimationOptionTransitionFlipFromBottom animations:^{

} completion:^(BOOL finished) {
if (finished) {
currentViewController=thirdViewController;
}else{
currentViewController=oldViewController;
}
}];
}
break;
default:
break;
}
}

其中我把按钮设置成不同的tag了。

这时候点击按钮，就可以切换子视图了。

这样写的好处：

多个UIViewController之间切换可以添加动画
当内存警告的时候，可以把当前不是激活状态的ViewController内存释放。
可以把代码更好分开

原文：http://wangjun.easymorse.com/?p=1630