UIBarButtonItem、UINavigationController

//在AppDelegate.m中

 

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    self.window = [[UIWindow alloc]initWithFrame:[UIScreen mainScreen].bounds];
    self.window.backgroundColor = [UIColor redColor];
   
    //创建一个视图控制器（创建之初就加载nib）
    OneViewController *oneVC = [[OneViewController alloc]initWithNibName:@"OneViewController" bundle:nil];
   
    //oneVC控制器的对象放在一个导航控制器的栈底（因为栈内存中只有这一个对象，栈底也就是栈顶，栈顶就是优先显示与窗口之上的对象）
    UINavigationController *navc = [[UINavigationController alloc]initWithRootViewController:oneVC];
//    [navc pushViewController:oneVC animated:YES];
    //窗口的根视图控制器接收navc（navc的类继承自UIViewController）
    self.window.rootViewController = navc;
   
    //窗口展示在屏幕的最前端
    [self.window makeKeyAndVisible];

    

    return YES;

}

/****************************************************************/

//通过pushViewController方法压栈

    [self.navigationController pushViewController:twoVC animated:YES];

//出栈的方式：

 

    //直接出栈，一直到栈底（仅剩一个控制器的时候）

    [self.navigationController popToRootViewControllerAnimated:YES];
   
    //指定栈内存中的某个控制器
    [self.navigationController popToViewController:fiveVC animated:YES];
    //一个一个的出栈

    [self.navigationController popViewControllerAnimated:YES];

/****************************************************************/

《UIBarButtonItem》:

 

UIBarButtonItem *leftItem = [[UIBarButtonItem alloc]initWithTitle:@"返回吗" style:UIBarButtonItemStylePlain target:self action:@selector(doReturn)];
    self.navigationItem.leftBarButtonItem = leftItem;
   
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeContactAdd];
    UIBarButtonItem *rightItem = [[UIBarButtonItem alloc]initWithCustomView:btn];
    self.navigationItem.rightBarButtonItem = rightItem;
   
    //显示副标题

    self.navigationItem.prompt = @"hello";