禁用时如何使 UIBarButton 不灰显？

Question

我有一个UIBarButton saveBarButton 将屏幕图像保存到相机胶卷。当用户按下saveBarButton 时，图像被保存并且UIBarButton saveBarButton 变为UIImage doneIcon 1.2 秒以向用户指示图像已被保存。当saveBarButton 显示doneIcon 时，我禁用saveBarButton。但是，当我这样做时，saveBarButton 是灰色的。

我的问题是：如何阻止 UIBarButton 在禁用时变灰？

我的代码：

//create UIBarButton saveBarButton
override func viewDidLoad() {    
    let saveBarButton = UIBarButtonItem(image: UIImage(named: "saveIcon"), style: .Plain, target: self, action: "save:")
    saveBarButton.tintColor = colorGreyDark
}

//save function called when press saveBarButton
func save(sender: UIBarButtonItem) {
    //save image
    deselectShape()
    let window: UIWindow! = UIApplication.sharedApplication().keyWindow
    let windowImage = capture(window)
    UIImageWriteToSavedPhotosAlbum(windowImage
        , nil, nil, nil)

    //Change saveBarButton to indicate to user that image was saved 
    sender.image = UIImage(named: "doneIcon")
    sender.enabled = false //disable saveBarButton
    self.performSelector("canSaveAgain:", withObject: sender, afterDelay: 1.2)
}

//Change saveBarButton to original icon to indicate to user that can save another image
func canSaveAgain(sender: UIBarButtonItem){
    sender.image = UIImage(named: "saveIcon")
    sender.enabled = true //enable saveBarButton
}

To see what I'm talking about.

Answer 1

其中一种方法是使用customView 创建UIBarButtonItem，并使用userInteractionEnabled 代替enabled。

let saveBarButton = UIBarButtonItem(customView: saveButton)
saveBarButton.customView?.userInteractionEnabled = false