如何更改Swift中多个组件的UIPickerView的文本颜色？

以下代码将更改所有3个组件的选取器视图的字体颜色。 但是，当我试图旋转轮子时，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？ 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 } 

Answer 1

下面的pickerView:attributedTitleForRow:forComponent:方法实现应该帮助你：

 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语句中使用的attributedString ，下面的UIViewController例子将帮助你：

 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 } override func didReceiveMemoryWarning() { super.didReceiveMemoryWarning() } 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 } } } 

Answer 2

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 }