给iPhone程序添加欢迎界面
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { [NSThread sleepForTimeInterval:5.0];self.window.rootViewController = self.viewController; [self.window makeKeyAndVisible]; return YES;}

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这样欢迎页面就停留5秒后消失了。