要使用UIPickerView必須要繼承UIPickerViewDataSource, UIPickerViewDelegate這兩個類別，在Storyboard放入Picker View的物件，並設IBOutlet，如下圖。
【片段程式碼】
func numberOfComponentsInPickerView(_: UIPickerView) -> Int {
return 1
}
設定有幾個元件在PickerView裡面，此範例設定為1。
func pickerView(_: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return 5
}
設定每個元件有幾個row，範例設定5個，表示有五個選項可以滑動選擇。
func pickerView(_pickerView: UIPickerView!, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString! {
let stringColor = UIColor(red: 255, green: 0, blue: 0, alpha: 1)
let attributes = [NSForegroundColorAttributeName: stringColor]
let showString = NSMutableAttributedString(string: "\(stringValue[row])", attributes: attributes)
return showString
}
這個func是在設定選項裡面的內容，上面程式碼回傳的是NSMutableAttributedString，showString 會夾帶String與attribute給UIPickerView。
func pickerView(_: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
switch row {
case 0...4:
myLabel.text = "Your choose is \(stringValue[row])."
default:
nil
}
}
這個func是對應到當PickerView的值被更動的時候所對應的動作。【完整的程式範例】
//
// ViewController.swift
// UIPickerView
//
// Created by Hsu,Yi-Sheng on 2014/6/23.
// Copyright (c) 2014年 yisheng. All rights reserved.
//
import UIKit
class ViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {
@IBOutlet var pickerView: UIPickerView
@IBOutlet var myLabel: UILabel
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
//設定有幾個元件
func numberOfComponentsInPickerView(_: UIPickerView) -> Int {
return 1
}
//設定每個元件中有幾個row
func pickerView(_: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return 5
}
var stringValue: String[] = ["A", "B", "C", "D", "E"]
//顯示PickerView內的資料
func pickerView(_pickerView: UIPickerView!, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString! {
let stringColor = UIColor(red: 255, green: 0, blue: 0, alpha: 1)
let attributes = [NSForegroundColorAttributeName: stringColor]
let showString = NSMutableAttributedString(string: "\(stringValue[row])", attributes: attributes)
return showString
}
//PickerView變更的時候所做的動作
func pickerView(_: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
switch row {
case 0...4:
myLabel.text = "Your choose is \(stringValue[row])."
default:
nil
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
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