Swift UIView自定義視圖在ViewController動作後不會更新

Question

我希望View Controller中的步進器在每次單擊它時更新我自定義的UIView中的顏色。我不確定問題是由類的實例引起的，還是變量的值（redd1,greenn1和bluee1）未被更改。

這是我的第一個文件：

class ViewController: UIViewController { 
    var colors = UIView1(); 
    @IBOutlet var redStepper: UIStepper! 
    @IBOutlet var greenStepper: UIStepper! 
    @IBOutlet var blueStepper: UIStepper! 

    @IBAction func redChange(sender: UIStepper) 
    { 
     redValue.text = Int(sender.value).description; 
     colors.redd1 = Double(sender.value); 
     //self.view.setNeedsDisplay() 
    } 
    @IBAction func greenChange(sender: UIStepper) 
    { 
     greenValue.text = Int(sender.value).description; 
     colors.greenn1 = Double(sender.value); 
     //self.view.setNeedsDisplay() 
    } 
    @IBAction func blueChange(sender: UIStepper) 
    { 
     blueValue.text = Int(sender.value).description; 
     colors.bluee1 = Double(sender.value); 
     //self.view.setNeedsDisplay() 
    } 
} 

這是我的第二個文件：

class UIView1: UIView { 
    var redd1 = 0.0; 
    var greenn1 = 0.0; 
    var bluee1 = 0.0; 

    override init(frame: CGRect) 
    { 
     super.init(frame: frame) 
    } 
    required init?(coder aDecoder: NSCoder) 
    { 
     super.init(coder: aDecoder) 
    } 
    override func drawRect(rect: CGRect) 
    { 
     let circle = UIView(frame: CGRect(x: -75.0, y: -40.0, width: 200.0, height: 200.0)) 
     circle.layer.cornerRadius = 50.0; 
     let startingColor = UIColor(red: (CGFloat(redd1))/255, green: (CGFloat(greenn1))/255, blue: (CGFloat(bluee1))/255, alpha: 1.0) 
     circle.backgroundColor = startingColor; 
     addSubview(circle); 
    } 
} 

Answer 1

drawRect添加視圖時纔會被調用，所以在你的榜樣，drawRect被調用一次，而不是在改變步進器之後。

相反，你的步進文件更改爲：

@IBOutlet var redStepper: UIStepper! 
@IBOutlet var greenStepper: UIStepper! 
@IBOutlet var blueStepper: UIStepper! 

@IBAction func redChange(sender: UIStepper) { 
    redValue.text = Int(sender.value).description; 
    colors.redd1 = Double(sender.value); 
    updateColor() 
} 

@IBAction func greenChange(sender: UIStepper) { 
    greenValue.text = Int(sender.value).description; 
    colors.greenn1 = Double(sender.value); 
    updateColor() 
} 

@IBAction func blueChange(sender: UIStepper) { 
    blueValue.text = Int(sender.value).description; 
    colors.bluee1 = Double(sender.value); 
    updateColor() 
} 

然後添加updateColor功能，以您的UIView1類：

class UIView1: UIView { 

    var redd1 = 0.0; 
    var greenn1 = 0.0; 
    var bluee1 = 0.0; 

    func updateColor() { 
     let circle = UIView(frame: CGRect(x: -75.0, y: -40.0, width: 200.0, height: 200.0)) 
     circle.layer.cornerRadius = 50.0; 
     let startingColor = UIColor(red: (CGFloat(redd1))/255, green: (CGFloat(greenn1))/255, blue: (CGFloat(bluee1))/255, alpha: 1.0) 
     circle.backgroundColor = startingColor; 
     addSubview(circle); 
    } 
}