我无法在我的ios应用程序中看到viewUtils.showActivityIndi​​cator

Question

我在我的应用中需要一个show activityindicator，但我无法看到它。我有我的viewutils（类型为viewcontrollerultis），我用这种方式调用它：viewUtils.showActivityIndi​​cator（self.view）。我不知道为什么会这样。

let viewUtils = ViewControllerUtils()
@IBAction func login(sender: AnyObject) {
    viewUtils.showActivityIndicator(self.view)

    username = userField.text.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
    password = passwordTextField.text.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())

        if (self.username.isEmpty || self.password.isEmpty){
            self.showAlert("Asegurese de ingresar un usuario y contraseña!")
            }else{

                var user = user_function()
                if user.user_valid(username,password: password){
                }else{
                    self.showAlert("Usuario Invalido")
                    }
            }
    viewUtils.hideActivityIndicator(self.view)


}

这是我的showactivityindicator：

func showActivityIndicator(uiView: UIView) {
    container.frame = uiView.frame
    container.center = uiView.center
    container.backgroundColor = UIColorFromHex(0xffffff, alpha: 0.3)

    loadingView.frame = CGRectMake(0, 0, 80, 80)
    loadingView.center = uiView.center
    loadingView.backgroundColor = UIColorFromHex(0x444444, alpha: 0.7)
    loadingView.clipsToBounds = true
    loadingView.layer.cornerRadius = 10

    activityIndicator.frame = CGRectMake(0.0, 0.0, 40.0, 40.0);
    activityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.WhiteLarge
    activityIndicator.center = CGPointMake(loadingView.frame.size.width / 2, loadingView.frame.size.height / 2);

    loadingView.addSubview(activityIndicator)
    container.addSubview(loadingView)
    uiView.addSubview(container)
    activityIndicator.startAnimating()
}