pragma mark ----- 获取window的方法 -----------

    //第一种: 获取当前view的window
    self.view.window.rootViewController = [[UIStoryboard storyboardWithName:@"Main" bundle:nil] instantiateInitialViewController];
    
    //第二种: 获取当前应用的window
    [UIApplication sharedApplication].keyWindow.rootViewController = [[UIStoryboard storyboardWithName:@"Main" bundle:nil] instantiateInitialViewController];