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我是 Swift 的新手，我正在制作一个基本的应用程序，用输入框中的文本更改标签的文本，我想添加 RGB 滑块来更改将要更改的标签的颜色，但我很快就遇到了错误当我尝试移动滑块时。

致命错误：在展开可选值 (lldb) 时意外发现 nil

@IBOutlet weak var OutputLabel: UILabel!
@IBOutlet weak var InputField: UITextField!

@IBOutlet weak var RedSlider: UISlider!
@IBOutlet weak var BlueSlider: UISlider!
@IBOutlet weak var GreenSlider: UISlider!

@IBOutlet weak var RedLabel: UILabel!
@IBOutlet weak var GreenLabel: UILabel!
@IBOutlet weak var BlueLabel: UILabel!


var RedColor : Float = 0
var GreenColor : Float = 0
var BlueColor : Float = 0

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


@IBAction func ChangeBtn(_ sender: Any) {
    OutputLabel.text = InputField.text
}

@IBAction func RedSliderAction(_ sender: UISlider) {
    changeColor()
}

@IBAction func GreenSliderAction(_ sender: UISlider) {
    changeColor()
}

@IBAction func BlueSliderAction(_ sender: UISlider) {
    changeColor()
}


func changeOutputLableColor() {
    OutputLabel.textColor = UIColor(red: CGFloat(RedColor), green: CGFloat(GreenColor), blue: CGFloat(BlueColor), alpha: 1.0)
    changeLabelNumbers()
}

func changeColor() {
    RedColor = RedSlider.value
    GreenColor = GreenSlider.value
    BlueColor = BlueSlider.value
    changeOutputLableColor()
}

func changeLabelNumbers() {
    let RoundedRed = String(format: "%0.0f", (RedColor * 255))
    let RoundedGreen = String(format: "%0.0f", (GreenColor * 255))
    let RoundedBlue = String(format: "%0.0f", (BlueColor * 255))

    RedLabel.text = "\(RoundedRed)"
    GreenLabel.text = "\(RoundedGreen)"
    BlueLabel.text = "\(RoundedBlue)"
}

有人可以帮我弄清楚吗？

4

1 回答 1

1

您可能尚未将 @IBOutlets RedSlider、BlueSlider 和/或 GreenSlider 连接到UISlider情节提要上的 。这将导致您收到错误。

或者，您可能没有连接@IBOutlets RedLabel、GreenLabel 和/或 BlueLabel。只需查找代码崩溃的行，它会提示您未连接的行。

于 2017-07-24T09:11:37.267 回答