Swift - 选择框（UIPickerView）的用法

import UIKit

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {

var pickerView:UIPickerView!

override func viewDidLoad() {
super.viewDidLoad()

// 创建UIPickerView控件
pickerView = UIPickerView()
self.view.addSubview(pickerView)

// 设置代理和数据源
pickerView.delegate = self;
pickerView.dataSource = self

// 设置选择框的默认值
pickerView.selectRow(1, inComponent: 0, animated: true)
pickerView.selectRow(2, inComponent: 1, animated: true)
pickerView.selectRow(3, inComponent: 2, animated: true)

// 创建一个按钮，点击按钮获得选择框被选中的索引
let button = UIButton(frame: CGRectMake(0,0,100,30))
button.center = self.view.center
button.backgroundColor = UIColor.blueColor()
button.setTitle("获取信息", forState: UIControlState.Normal)
button.addTarget(self, action: #selector(getPikerViewValue), forControlEvents: UIControlEvents.TouchUpInside)
self.view.addSubview(button)
}

/**
获取选择框被选中的索引的方法
*/
func getPikerViewValue(){
print("被选中的索引为：\(pickerView.selectedRowInComponent(0))、\(pickerView.selectedRowInComponent(1))、\(pickerView.selectedRowInComponent(2))")
}

// MARK: UIPickerViewDataSource
/**
设置选择框的列数
*/
func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
return 3
}

/**
设置选择框的行数
*/
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return 9
}

// MARK:UIPickerViewDelegate
/**
设置选择框各选项的内容
*/
func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return String(row) + "-" + String(component)
}
}