学习笔记:UIPickerView

利用UIPickerView控件实现省市区三级联动的效果，如下图：

代码是转载http://www.hangge.com/blog/cache/detail_1169.html
，稍有修改

代码如下：

import UIKitclass ViewController: UIViewController,UIPickerViewDataSource,UIPickerViewDelegate {    @IBOutlet weak var picker: UIPickerView!    @IBOutlet weak var btn: UIButton!    //所以地址数据集合    var addressArray = [[String: AnyObject]]()    //var addressArray:NSArray!    //选择的省索引    var provinceIndex = 0    //选择的市索引    var cityIndex = 0    //选择的县索引    var areaIndex = 0    override func viewDidLoad() {        super.viewDidLoad()        // Do any additional setup after loading the view, typically from a nib.        let path = NSBundle.mainBundle().pathForResource("address", ofType:"plist")        addressArray = NSArray(contentsOfFile: path!) as! Array    }    override func didReceiveMemoryWarning() {        super.didReceiveMemoryWarning()        // Dispose of any resources that can be recreated.    }    //设置选择器的列数    func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {        return 3    }    //设置选择器的行数    func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {        if component == 0 {            return self.addressArray.count        } else if component == 1 {            let province = self.addressArray[provinceIndex]            return province["cities"]!.count        } else {            let province = self.addressArray[provinceIndex]            if let city = province["cities"]![cityIndex] as? [String: AnyObject] {                return city["areas"]!.count            } else {                return 0            }        }    }    //设置选择框各选项的内容，继承于UIPickerViewDelegate协议    func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int)        -> String? {            if component == 0 {                return self.addressArray[row]["state"] as? String            }else if component == 1 {                let province = self.addressArray[provinceIndex]                return province["cities"]![row]["city"] as? String            }else {                let province = self.addressArray[provinceIndex]                let city = province["cities"]![cityIndex] as? [String: AnyObject]                return city!["areas"]![row] as? String            }    }    //选中项改变事件（将在滑动停止后触发）    func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {        //根据列、行索引判断需要改变数据的区域        switch (component) {        case 0:            provinceIndex = row;            cityIndex = 0;            areaIndex = 0;            pickerView.reloadComponent(1);            pickerView.reloadComponent(2);            pickerView.selectRow(0, inComponent: 1, animated: false);            pickerView.selectRow(0, inComponent: 2, animated: false);        case 1:            cityIndex = row;            areaIndex = 0;            pickerView.reloadComponent(2);            pickerView.selectRow(0, inComponent: 2, animated: false);        case 2:            areaIndex = row;        default:            break;        }    }    //触摸按钮时，获得被选中的索引    @IBAction func getPickerViewValue(){        //获取选中的省        let p = self.addressArray[provinceIndex]        let province = p["state"]!        //获取选中的市        let c = p["cities"]![cityIndex]        let city = c["city"] as! String        //获取选中的县（地区）        var area = ""        if (c["areas"] as! [String]).count > 0 {            area = (c["areas"] as! [String])[areaIndex]        }        //拼接输出消息        let message = "索引：\(provinceIndex)-\(cityIndex)-\(areaIndex)\n"            + "值：\(province) - \(city) - \(area)"        //消息显示        let alertController = UIAlertController(title: "您选择了",                                                message: message, preferredStyle: .Alert)        let cancelAction = UIAlertAction(title: "确定", style: .Cancel, handler: nil)        alertController.addAction(cancelAction)        self.presentViewController(alertController, animated: true, completion: nil)    }}