ios – 如何在Swift中使用多个组件更改UIPickerView的文本颜色？

发布时间：2020-12-15 01:43:54 所属栏目：百科来源：网络整理

导读：下面的代码将更改所有3个组件的选择器视图的字体颜色.但是,当我试图旋转车轮时,它会崩溃.我认为它与didSelectRow函数有关.也许两个函数必须以某种方式嵌套？任何想法？ func pickerView(pickerView: UIPickerView,attributedTitleForRow row: Int,forCompone

下面的代码将更改所有3个组件的选择器视图的字体颜色.但是,当我试图旋转车轮时,它会崩溃.我认为它与didSelectRow函数有关.也许两个函数必须以某种方式嵌套？任何想法？

func pickerView(pickerView: UIPickerView,attributedTitleForRow row: Int,forComponent component: Int) -> NSAttributedString? {
    var attributedString: NSAttributedString!
    if component == 0 {
        attributedString = NSAttributedString(string: a.text!,attributes: [NSForegroundColorAttributeName : UIColor.redColor()])
    }
    if component == 1 {
        attributedString = NSAttributedString(string: b.text!,attributes: [NSForegroundColorAttributeName : UIColor.redColor()])
    }
    if component == 2 {
        attributedString = NSAttributedString(string: c.text!,attributes: [NSForegroundColorAttributeName : UIColor.redColor()])
    }
    return attributedString
}


func pickerView(pickerView: UIPickerView,didSelectRow row: Int,inComponent component: Int){

    switch component {
    case 0:
        aOutput.text = a[row]      -->  **Code breaks**
    case 1:
        bOutput.text = b[row]
    case 2:
        cOutput.text = c[row]
    default:
        10
    }

解决方法

以下pickerView：attributionTitleForRow：forComponent：方法实现应该可以帮助您：

func pickerView(pickerView: UIPickerView,forComponent component: Int) -> NSAttributedString? {
    let attributedString = NSAttributedString(string: "some string",attributes: [NSForegroundColorAttributeName : UIColor.redColor()])
    return attributedString
}

更新

如果要在多个if或switch语句中使用attributedString,以下UIViewController子类示例将帮助您：

import UIKit

class ViewController: UIViewController,UIPickerViewDelegate,UIPickerViewDataSource {

    @IBOutlet weak var picker: UIPickerView!

    let arrayOne = ["One","Two","Three","Four","Five","Six"]
    let arrayTwo = ["Un","Deux","Trois","Quatre","Cinq","Six"]
    let arrayThree = [1,2,3,4,5,6]


    override func viewDidLoad() {
        super.viewDidLoad()

        picker.delegate = self
        picker.dataSource = self
    }

    func numberOfComponentsInPickerView(_: UIPickerView) -> Int {
        return 3
    }

    func pickerView(_: UIPickerView,numberOfRowsInComponent component: Int) -> Int {
        switch component {
        case 0:
            return arrayOne.count
        case 1:
            return arrayTwo.count
        case 2:
            return arrayThree.count
        default:
            return NSNotFound
        }
    }

    func pickerView(pickerView: UIPickerView,forComponent component: Int) -> NSAttributedString? {
        var attributedString: NSAttributedString!

        switch component {
        case 0:
            attributedString = NSAttributedString(string: arrayOne[row],attributes: [NSForegroundColorAttributeName : UIColor.redColor()])
        case 1:
            attributedString = NSAttributedString(string: arrayTwo[row],attributes: [NSForegroundColorAttributeName : UIColor.redColor()])
        case 2:
            attributedString = NSAttributedString(string: toString(arrayThree[row]),attributes: [NSForegroundColorAttributeName : UIColor.redColor()])
        default:
            attributedString = nil
        }

        return attributedString
    }

    func pickerView(_: UIPickerView,inComponent component: Int) {
        switch component {
        case 0:
            println(arrayOne[row])
        case 1:
            println(arrayTwo[row])
        case 2:
            println(arrayThree[row])
        default:
            break
        }
    }

}

（编辑：李大同）

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