iOS 导航条（navigation）

1.初始化

-(BOOL)application:(UIApplication *)applicationdidFinishLaunchingWithOptions:(NSDictionary*)launchOptions

{

   self.window = [[[UIWindow alloc]initWithFrame:[[UIScreen mainScreen] bounds]]autorelease];

   self.viewController = [[[ViewController alloc]initWithNibName:@"ViewController" bundle:nil]autorelease];

   UINavigationController *nav =[[[UINavigationController alloc]initWithRootViewController:self.viewController]autorelease];

   nav.navigationBar.barStyle =UIBarStyleBlack;

   self.window.rootViewController =nav;

   [self.window makeKeyAndVisible];

   return YES;

}

2.更改导航条上返回按钮的标题

UIBarButtonItem *barButtonItem =[[UIBarButtonItem alloc] init];

barButtonItem.title =@"buttonName";

self.navigationItem.backBarButtonItem =barButtonItem; 

[barButtonItem release]

3.返回到上一个视图，返回根视图以及返回到任意视图

//返回到上一个视图，比如用户单击导航栏的Back按钮

[[self navigationController]popViewControllerAnimated:YES]

//返回到根视图

[[self navigationController]popToRootViewControllerAnimated:YES];

//返回到任意视图

[[self navigationController]popToViewController:destiationViewControlleranimated:YES];

4.添加自定义视图到导航条的标题栏

该代码添加一个自定义的UILabel，但也可以添加其他任意控件（或者视图），比如UIImageView，UISwitch等等。

self.navigationItem.titleView = [[[UILabelalloc] 

     initWithFrame:CGRectMake(0.0f,0.0f, 120.0f,36.0f)] autorelease];

self.title = @"Hello";

5.为导航添加新按钮

修改navigationItem可以为导航栏添加新按钮，如果要删除按钮，将该项指定为空值即可。下面代码是为导航栏添加右边按钮

self.navigationItem.rightBarButtonItem =[[[UIBarButtonItem alloc] initWithTitle:@"Action"style:UIBarButtonItemStylePlain target:selfaction:@selector(performAction:)] autorelease];