Xcode6及以上
版本 删除stroyBord后的启动方法

清空后，在AppDelegate.m里

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    // Override point for customization after application launch.

    

    self.window = [[UIWindowalloc]initWithFrame:[[UIScreenmainScreen]bounds]];

    /*

     写代码区

self.window.rootViewController = XXxXX;

     */

    [self.windowmakeKeyAndVisible];

    returnYES;

}