UIApplication的作用

UIApplication的作用--演示：

    - (void)viewDidLoad {

    [superviewDidLoad];

    UIApplication*app = [UIApplicationsharedApplication];

    UIUserNotificationSettings*settings = [UIUserNotificationSettingssettingsForTypes:UIUserNotificationTypeBadgecategories:nil];

      //注册通知

     [appregisterUserNotificationSettings:settings];

     //1.设置应用程序图标提醒数字

       app.applicationIconBadgeNumber=0;

     //2.设置联网状态

      app.networkActivityIndicatorVisible=YES;

      //3.设置状态栏

      //在iOS7之后状态栏都是交给控制器管理，不用下方的代码了。

     app.statusBarHidden = YES;

       [app setStatusBarHidden:YES withAnimation:UIStatusBarAnimationSlide];

       //4.打电话,发短信,打开网页.

       URL:资源唯一路径

       //http://www.baidu.com

      //URL:协议头//路径//       http://

      //其实苹果就是根据协议头判断用什么软件去打开

      NSURL*url = [NSURLURLWithString:@"http://www.baidu.com"];

      [appopenURL:url];

        }

          //隐藏状态栏

        -(BOOL)prefersStatusBarHidden

         {

         return YES;

           }