Question

当我点击UIButton saveButton时，我希望saveButton将图片从saveIcon更改为doneIcon，持续时间为1.2秒。我已经这样实现了：

override func viewDidLoad() {
    //create save button
    let saveButton = UIButton(frame: CGRectMake(0, preview.frame.maxY + space, buttonSize, buttonSize))
    saveButton.setBackgroundImage(UIImage(named: "saveIcon"), forState: .Normal)
    saveButton.setBackgroundImage(UIImage(named: "doneIcon"), forState: .Disabled)
    saveButton.center.x = returnButton.center.x
    saveButton.addTarget(self, action: "save:", forControlEvents: .TouchUpInside)
    saveButton.addTarget(self, action: "canSaveAgain:", forControlEvents: .TouchUpInside)
    self.view.addSubview(saveButton)
}

func save(sender: UIButton){
    UIImageWriteToSavedPhotosAlbum(masterpiece, nil, nil, nil)
    sender.enabled = false
    self.performSelector("canSaveAgain:", withObject: sender, afterDelay: 1.2)
}

func canSaveAgain(sender: UIButton){
    sender.enabled = true
}

虽然正在启用和禁用saveButton，但即使我在禁用时将其图片设置为saveButton，doneIcon也不会更改其图像（即saveButton.setBackgroundImage(UIImage(named: "doneIcon"), forState: .Disabled) ）。

如果有人能告诉我为什么会发生这种情况以及如何暂时改变UIButton的形象，我将非常感激！

Answer 1

我发现了我的问题！实际上，当我点击UIButton时，我有两种方法被调用。也就是说，当我按下按钮时，我正在调用save: 和 canSaveAgain:。结果，我同时将按钮设置为禁用并立即启用。

我编辑的代码：

override func viewDidLoad() {
    super.viewDidLoad()

    //create save button
    let saveButton = UIButton(frame: CGRectMake(0, preview.frame.maxY + space, buttonSize, buttonSize))
    saveButton.setImage(UIImage(named: "saveIcon"), forState: .Normal)
    saveButton.setImage(UIImage(named: "doneIcon"), forState: .Disabled)
    saveButton.center.x = returnButton.center.x
    saveButton.addTarget(self, action: "save:", forControlEvents: .TouchUpInside)
    self.view.addSubview(saveButton)
}

func save(sender: UIButton){
    UIImageWriteToSavedPhotosAlbum(masterpiece, nil, nil, nil)
    sender.enabled = false
    self.performSelector("canSaveAgain:", withObject: sender, afterDelay: 1.0)
}

func canSaveAgain(sender: UIButton){
    sender.enabled = true
}

UIButton没有图像？

1 个答案: