Ios 在Swift中进行有效选择时，如何在带有多个组件的UIPickerView视图中更改文本的背景色

下面的代码将UIPickerView的背景色更改为青色，表明行索引总数=6时它是有效的选择。希望在视图中选择pickerLabel background，以便在选择有效时在所有四个组件中变为青色。有什么想法吗

import UIKit

class ViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {

    @IBOutlet weak var myPicker: UIPickerView!
    let pickerData0 = ["0R","1R","2R","3R","4R","5R","6R"]
    let pickerData1 = ["0B","1B","2B","3B","4B","5B","6B"]
    let pickerData2 = ["0Y","1Y","2Y","3Y","4Y","5Y","6Y"]
    let pickerData3 = ["0G","1G","2G","3G","4G","5G","6G"]

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        myPicker.dataSource = self
        myPicker.delegate = self

    }

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


    //Mark: Delegates and data sources
    //Mark: Data Sources
    func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
        return 4
    }

    func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return pickerData0.count
    }
    //Mark: Delegates

    func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        let redIndex = myPicker.selectedRowInComponent(0)
        let blueIndex = myPicker.selectedRowInComponent(1)
        let yellowIndex = myPicker.selectedRowInComponent(2)
        let greenIndex = myPicker.selectedRowInComponent(3)

        if redIndex + blueIndex + yellowIndex + greenIndex == 6 {
            myPicker.backgroundColor = UIColor.cyanColor()
        } else {
            myPicker.backgroundColor = UIColor.whiteColor()
        }   
    }


    func pickerView(pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusingView view: UIView!) -> UIView {

        switch component {
        case 0:
            var pickerLabel = view as! UILabel!
            if view == nil {
                pickerLabel = UILabel()
                pickerLabel.textColor = UIColor.redColor()
                pickerLabel.backgroundColor = UIColor.grayColor()
                pickerLabel.textAlignment = NSTextAlignment.Center
                pickerLabel.text = pickerData0[row]
                pickerLabel.font = UIFont(name: "Georgia", size: 26)
            }
            return pickerLabel
        case 1:
            var pickerLabel = view as! UILabel!
            if view == nil {
                pickerLabel = UILabel()
                pickerLabel.textColor = UIColor.blueColor()
                pickerLabel.backgroundColor = UIColor.grayColor()
                pickerLabel.textAlignment = NSTextAlignment.Center
                pickerLabel.text = pickerData1[row]
                pickerLabel.font = UIFont(name: "Georgia", size: 26)
            }
            return pickerLabel
        case 2:
            var pickerLabel = view as! UILabel!
            if view == nil {
                pickerLabel = UILabel()
                pickerLabel.textColor = UIColor.yellowColor()
                pickerLabel.backgroundColor = UIColor.grayColor()
                pickerLabel.textAlignment = NSTextAlignment.Center
                pickerLabel.text = pickerData2[row]
                pickerLabel.font = UIFont(name: "Georgia", size: 26)
            }
            return pickerLabel
        case 3:
            var pickerLabel = view as! UILabel!
            if view == nil {
                pickerLabel = UILabel()
                pickerLabel.textColor = UIColor.greenColor()
                pickerLabel.backgroundColor = UIColor.grayColor()
                pickerLabel.textAlignment = NSTextAlignment.Center
                pickerLabel.text = pickerData3[row]
                pickerLabel.font = UIFont(name: "Georgia", size: 26)
            }
            return pickerLabel
        default:
          return pickerView
        }
    }
}

---

您希望选中viewselected中的pickerLabel背景，以在所有四个组件中变为青色。您可以更改pickviewdidSelectRow中的代码：

if redIndex + blueIndex + yellowIndex + greenIndex == 6 {
        myPicker.backgroundColor = UIColor.cyanColor()
    } else {
        myPicker.backgroundColor = UIColor.whiteColor()
    }  

致：

---

顺便说一句，我不确定是否适合你的需要。

谢谢你让我走上正轨。我对代码进行了如下修改，使所有四个背景选择器标签都变成青色。

if redIndex + blueIndex + yellowIndex + greenIndex == 6 {
  myPicker.viewForRow(row, forComponent: component)?.backgroundColor = UIColor.cyanColor()
} else {
  myPicker.viewForRow(row, forComponent: component)?.backgroundColor = UIColor.whiteColor()
}