ios - 如何快速更新实例变量？

Question

我希望当单击步进器时圆圈的颜色发生变化。我相信问题是我正在使用该类的实例。

这是我的第一个文件:

class ViewController: UIViewController {

@IBOutlet var redValue: UILabel!
@IBOutlet var greenValue: UILabel!
@IBOutlet var blueValue: UILabel!

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

var redd = 0.0;
var greenn = 0.0;
var bluee = 0.0;

@IBAction func redChange(sender: UIStepper)
{
    redValue.text = Int(sender.value).description;
    redd = sender.value;
}
@IBAction func greenChange(sender: UIStepper)
{
    greenValue.text = Int(sender.value).description;
    greenn = sender.value;
}
@IBAction func blueChange(sender: UIStepper)
{
    blueValue.text = Int(sender.value).description;
    bluee = sender.value;
}

}

这是我的第二个文件:

class UIView1: UIView {

var colors = ViewController();

required init?(coder aDecoder: NSCoder)
{
    super.init(coder: aDecoder)
}

override func drawRect(rect: CGRect)
{ 
    let circle2 = UIView(frame: CGRect(x: -25.0, y: 10.0, width: 100.0, height:100.0))
    circle2.layer.cornerRadius = 50.0
    let startingColor2 = UIColor(red: (CGFloat(colors.redd)/255), 
           green: (CGFloat(colors.greenn))/255, blue: (CGFloat(colors.bluee))/255, alpha: 1.0)
    circle2.backgroundColor = startingColor2;
    addSubview(circle2);    
}

}

Answer 1

可能存在各种连接问题，因为我们看不到该代码/IB。但是，我怀疑您至少错过了通知 View 需要重绘自身的调用，因为基础值已更改。

self.view.setNeedsDisplay()

这是我用来试验的整个 Playground ，对您的代码进行了各种修改。检查最后一个副本以查看更改。注意:UI 元素实际上并未创建，我在手动设置 UIStepper.value 后模拟了一个光滑的效果。

import UIKit

class ViewController: UIViewController {

    @IBOutlet var redValue: UILabel!
    @IBOutlet var greenValue: UILabel!
    @IBOutlet var blueValue: UILabel!

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

    var redd = 100.0;
    var greenn = 100.0;
    var bluee = 100.0;

    @IBAction func redChange(sender: UIStepper)
    {
        redValue?.text = Int(sender.value).description
        redd = sender.value
        self.view.setNeedsDisplay()
    }
    @IBAction func greenChange(sender: UIStepper)
    {
        greenValue.text = Int(sender.value).description
        greenn = sender.value
    }
    @IBAction func blueChange(sender: UIStepper)
    {
        blueValue.text = Int(sender.value).description
        bluee = sender.value
    }
}


class UIView1: UIView {

    var colors = ViewController()

    override init(frame: CGRect) {
        super.init(frame: frame)
    }

    required init?(coder aDecoder: NSCoder)
    {
        super.init(coder: aDecoder)
    }

    override func drawRect(rect: CGRect)
    {
        let circle2 = UIView(frame: CGRect(x: -25.0, y: 10.0, width: 100.0, height:100.0))
        circle2.layer.cornerRadius = 50.0
        let startingColor2 = UIColor(red: CGFloat(colors.redd/255.0),
            green: (CGFloat(colors.greenn))/255,
            blue: (CGFloat(colors.bluee))/255,
            alpha: 1.0)
        circle2.backgroundColor = startingColor2;
        addSubview(circle2);    
    }
}

let v = UIView1(frame: CGRectMake(0,0,400, 240))
v.colors.view = v

let rstepper = UIStepper(frame: CGRectMake(0,0,300,50))
rstepper.maximumValue = 255.0
rstepper.value = 240.0
v.colors.redChange(rstepper)


// inspect the view now:
v