欢迎界面停留2秒后进入主程序界面

直接在欢迎界面的viewDidLoad中使用如下方法即可。  

  [self performSelector:@selector(GoToViewController) withObject:nil afterDelay:2]; //2秒后，进入应用程序的主界面

在GoToViewController 方法中写如下代码：

-(void)GoToViewController

{

    MainViewController *myMainViewController = [[MainViewController alloc]initWithNibName:@"MainViewController" bundle:nil];

    [self.view addSubview:myMainViewController.view];

}

如果为欢迎页面增加淡入淡出效果，则将 GoToViewController 方法修改如下：

-(void)GoToViewController
{
    CATransition *animation = [CATransition animation];
    animation.delegate = self;
    animation.duration = 0.7 ;  // 动画持续时间(秒)
    animation.timingFunction = UIViewAnimationCurveEaseInOut;
    animation.type = kCATransitionFade;//淡入淡出效果
    [[self.view layer]addAnimation:animation forKey:@"animation"];
    
    MainViewController *myMainViewController = [[MainViewController alloc]initWithNibName:@"MainViewController" bundle:nil];
    [self.view addSubview:myMainViewController.view];
}