如何在Swift中更改UIPickerView多个组件的文本颜色？

Question

如何在Swift中更改UIPickerView多个组件的文本颜色？

20

以下代码将更改所有三个组件的选择器视图的字体颜色。但是，当我尝试旋转轮子时，它会崩溃。我认为这与didSelectRow函数有关。也许这两个函数必须以某种方式嵌套？有什么想法吗？

    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
    }

- KML

4

你尝试过什么吗？在询问之前，你应该努力尝试一些方法。 - lagivan

1

当然，我花了数小时的时间，参加了两门课程——从零开始，没有编程背景，连续一周不停地开发这个应用程序。但是很难，所有的教程都在playground中。所以，虽然我能理解逻辑，但我很难理解代码放在哪里。所有的初始化（我想它被称为）和Swift/Object C的范围。 - KML

作用域。如果你不理解像“var mySpeechSynthesizer: AVSpeechsynthesizer…”这样的语句是什么意思，它应该放在哪里，以及如何调用它们以及调用它们的顺序和名称，那么知道在Playground中如何编写switch/case语句也没有帮助。我甚至不知道我不知道的东西的名字...哈哈，你怎么能在不问别人的情况下弄清楚这些东西呢？告诉我吧，因为我在电子书、课程或Youtube上都找不到答案。 - KML

5个回答

18

Swift 4.0

func pickerView(_ pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? {
    return NSAttributedString(string: pickerData[row], attributes: [NSAttributedStringKey.foregroundColor : UIColor.white])
}

- Thinesh

8

Swift 3

func pickerView(_ pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? {
        let attributedString = NSAttributedString(string: "YOUR STRING", attributes: [NSForegroundColorAttributeName : UIColor.white])
        return attributedString
    }

- Marcos Reboucas

2

Swift 5

func pickerView(_ pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? {
    return NSAttributedString(string: pickerData[row], attributes: [NSAttributedString.Key.foregroundColor : UIColor.white])
}

- Kevin Singh

1

在此输入图像描述这段代码片段对我有效

extension UIPickerView {
@IBInspectable var pickerTextColor:UIColor? {
    get {
        return self.pickerTextColor
    }
    set {
        self.setValue(newValue, forKeyPath: "textColor")
    }
}}

- Abhi Kapoor

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- Imanou Petit · Accepted Answer

以下pickerView:attributedTitleForRow:forComponent:方法的实现应该能够帮助您：

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

更新

如果你想在多个if或switch语句中使用attributedString，下面的UIViewController子类示例可以帮助你：

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, attributedTitleForRow row: Int, 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, didSelectRow row: Int, inComponent component: Int) {
        switch component {
        case 0:
            println(arrayOne[row])
        case 1:
            println(arrayTwo[row])
        case 2:
            println(arrayThree[row])
        default:
            break
        }
    }

}