- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    //创建窗口
    self.window =[[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
    //加载main.storyboard 创建控制器
    UIStoryboard * stotyboard=[UIStoryboard storyboardWithName:@"main" bundle:nil];
    //1.加载箭头指向的控制器
    UIViewController *vc = [stotyboard instantiateInitialViewController];
    
    
    //设置跟控制器
    self.window.rootViewController=vc;
    
    //显示窗口
    [self.window makeKeyAndVisible];
    return YES;
}