改变状态栏颜色为白字黑底：

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {    UIApplication.sharedApplication().setStatusBarStyle(UIStatusBarStyle.LightContent, animated: false)}

另外要在info里面加上View controller-based status bar appearance  设置为  NO