ios - Swift - 即使控件可见， View 也不显示/更新控件

Question

对这个可怕的标题表示歉意，但我真的想不出更好的方式来表达它。我的代码如下:

@IBAction func btnSaveTapped(sender: UIButton) {
    println("Save Button Pressed")
    self.StartAI()
    self.btnSave.enabled = false
    self.AnimateButton(sender)

    var booContinueWithSend:Bool = true
    (Continues)

当我运行上面的代码时，屏幕上的控件没有变化。我已经单步执行了代码，每一行都没有变化。即使对于 btnSave.enabled 也没有任何变化。我已通过控制台调试器确认该按钮未启用，但它仍然显示为启用状态。是的，我已将其设置为根据状态明显改变(代码如下):

self.btnSave.setTitleColor(conButtonTextColour, forState: UIControlState.Normal)
self.btnSave.setTitleColor(conButtonTextColourDisabled, forState: UIControlState.Disabled)

其中 conButtonTextColour 为 UIColor.blackColor，conButtonTextColourDisabled 为灰色。

我的事件指示器也会发生这种情况，我已成功手动测试了该指示器。当我运行上面的代码(btnSaveTapped)时，没有任何反应(它没有像应有的那样显示)。我在这里以编程方式创建人工智能:

func CreateAI() {
    let conAIViewHeightWidth:CGFloat = 100
    let conHeightWidth:CGFloat = 50

    self.aiView.setTranslatesAutoresizingMaskIntoConstraints(false)
    self.view.addSubview(self.aiView)
    self.aiView.backgroundColor = UIColor(red: 0, green: 0, blue: 0, alpha: 0.3)
    self.aiView.layer.cornerRadius = 10

    var constraintViewHeight:NSLayoutConstraint = NSLayoutConstraint(item: self.aiView, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: conAIViewHeightWidth)
    var constraintViewWidth:NSLayoutConstraint = NSLayoutConstraint(item: self.aiView, attribute: NSLayoutAttribute.Width, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: conAIViewHeightWidth)
    self.aiView.addConstraints([constraintViewHeight, constraintViewWidth])

    var constraintViewX:NSLayoutConstraint = NSLayoutConstraint(item: self.aiView, attribute: NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: self.view, attribute: NSLayoutAttribute.CenterX, multiplier: 1, constant: 0)
    var constraintViewY:NSLayoutConstraint = NSLayoutConstraint(item: self.aiView, attribute: NSLayoutAttribute.CenterY, relatedBy: NSLayoutRelation.Equal, toItem: self.view, attribute: NSLayoutAttribute.CenterY, multiplier: 1, constant: 0)
    self.view.addConstraints([constraintViewX, constraintViewY])


    self.aiActivityIndicator.setTranslatesAutoresizingMaskIntoConstraints(false)
    self.aiView.addSubview(self.aiActivityIndicator)
    self.aiActivityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.WhiteLarge


    var constraintX:NSLayoutConstraint = NSLayoutConstraint(item: self.aiActivityIndicator, attribute: NSLayoutAttribute.CenterX, relatedBy: NSLayoutRelation.Equal, toItem: self.aiView, attribute: NSLayoutAttribute.CenterX, multiplier: 1, constant: 0)
    var constraintY:NSLayoutConstraint = NSLayoutConstraint(item: self.aiActivityIndicator, attribute: NSLayoutAttribute.CenterY, relatedBy: NSLayoutRelation.Equal, toItem: self.aiView, attribute: NSLayoutAttribute.CenterY, multiplier: 1, constant: 0)
    self.view.addConstraints([constraintX, constraintY])

    self.aiActivityIndicator.hidesWhenStopped = true
    self.aiActivityIndicator.startAnimating()

    StopAI()
}

这是我分别启动和停止人工智能的两个例程。因为 AI 是 aiView 的 subview ，所以我只是隐藏或取消隐藏它。然而，面对这些问题，我决定变得 super 安全，并确保我取消隐藏并启用人工智能。

func StartAI() {
    self.aiView.hidden = false
    self.aiActivityIndicator.hidden = false
    self.aiActivityIndicator.startAnimating()
    println("Started AI")
}

func StopAI() {
    self.aiView.hidden = true
    println("Stopped AI")
}

我做错了什么？提前致谢。

Answer 1

试试这个代码:

view.layoutIfNeeded()

完成所有更改后实现此操作