Swift UIPickerView

import UIKit

class ViewController: UIViewController,UIPickerViewDataSource,UIPickerViewDelegate {

    @IBOutlet weak var label1: UILabel!
    @IBOutlet weak var label2: UILabel!
    @IBOutlet weak var label3: UILabel!

    let arrData = ["北京","上海","广州"]

    override func viewDidLoad() {
        super.viewDidLoad()

        let pickerView = UIPickerView.init()
        pickerView.frame = CGRectMake(0,20,self.view.frame.size.width,200)
        pickerView.delegate = self;
        pickerView.dataSource = self;
        self.view .addSubview(pickerView)
    }

    func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
        return arrData.count
    }

    func pickerView(pickerView: UIPickerView,numberOfRowsInComponent component: Int) -> Int {
        return arrData.count
    }

    func pickerView(pickerView: UIPickerView,titleForRow row: Int,forComponent component: Int) -> String? {
        return arrData[row]
    }

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

        switch component {
        case 0 : label1.text = arrData[row]
        case 1 : label2.text = arrData[row]
        case 2 : label3.text = arrData[row]
        default: break
        }
    }

}