使用NGUI制作关联下拉菜单（查询全国天气）

using UnityEngine;
using System.Collections;

public class Global  {
    public static string areaUrl = "http://v.juhe.cn/weather/citys";     //支持的城市 ，在聚合数据/天气预报的第6条
    public static string weatherUrl = "http://v.juhe.cn/weather/index";  //更加城市名或id查询天气 ，在聚合数据/天气预报的第1条
    public static string appKey = "您申请的AppKey";   //申请是appkey
}

using UnityEngine;
using System.Collections;
using LitJson;      //引入 LitJson

public class Weather : MonoBehaviour {
    public UIPopupList provincePopupList;  //省份
    public UILabel provinceLable;        //显示省份的label
    public UIPopupList cityPopupList;   //城市
    public UILabel cityLable;          //显示城市的label
    public UIPopupList districtPopupList;  //区/县
    public UILabel districtLable;     //显示区/县的label
    public UILabel lable;    //显示结果的label

    private JsonData resultData;   //请求到的城市数据

    void Start()
    {
        provincePopupList.Clear();     //清空省份list
        StartCoroutine(RequestData());  //开启协程开请求区域数据
    }

    //选择城市，当我们的省份的provincePopupList的值发生变化时，我们调用这个方法，来更新城市
    public void SelectCity()      
    {
        cityPopupList.Clear();    //情况城市List
        for (int i = 0; i < resultData.Count; i++)
        {
            //遍历区域数据，找到省份List上的省份
            if (resultData[i]["province"].ToString().Equals(provinceLable.text))
            {
                //不存在这个城市，加到城市List上
                if (!cityPopupList.items.Contains(resultData[i]["city"].ToString()))
                    cityPopupList.AddItem(resultData[i]["city"].ToString());
            }
        }
    }
    //选择曲线，当我们的省份的cityPopupList的值发生变化时，我们调用这个方法，来更新区县
    public void SelectDistrict()
    {
        districtPopupList.Clear();  //清空曲线List
        for (int i = 0; i < resultData.Count; i++)
        {
            //遍历区域数据，找到城市List上的城市
            if (resultData[i]["city"].ToString().Equals(cityLable.text))
            {
                //不存在这个区县，加到区县List上
                if (!districtPopupList.items.Contains(resultData[i]["district"].ToString()))
                    districtPopupList.AddItem(resultData[i]["district"].ToString());
            }
        }
    }

    //展示天气
    public void ShowWeather()
    {
        //拼接请求城市的Url
        Global.weatherUrl = Global.weatherUrl + "?format=2&cityname=" + GetUTF8(districtLable.text) + "&key=" + Global.appKey;
        StartCoroutine(RequestWeatherData(Global.weatherUrl));   //开启协程来查询天气数据
    }
    //将字符串转换成UTF8编码，因为根据城市名称来请求数据是，需要传入的城市名为UTF8编码格式的
    private string GetUTF8(string str)
    {
        byte[] buffer = System.Text.Encoding.UTF8.GetBytes(str); 
        return System.Text.Encoding.UTF8.GetString(buffer);
    }
    //协程，用来请求区域数据
    IEnumerator RequestData()
    {
        WWW www = new WWW(Global.areaUrl + "?key="+ Global.appKey);      //拼接请求区域URL
        while (!www.isDone)
        {
            //没有完成
            yield return null;
        }
        if (www.error == null)     //没有错误
        {
            JsonData data = JsonMapper.ToObject(www.text);   //将请求到的Json 数据转换成 JsonData对象
            resultData = data["result"];  //将结果，赋值给我们的resultData ，因为后面还要用到这个数据来刷新城市和区县
            for (int i = 0; i < resultData.Count; i++)
            {   
                //遍历区域数据，如果没有这个省份，则加上
                if (!provincePopupList.items.Contains(resultData[i]["province"].ToString()))
                    provincePopupList.AddItem(resultData[i]["province"].ToString());
            }
        }
        else  //请求出错
            print(www.error);
    }
    //请求天气情况的协程
    IEnumerator RequestWeatherData(string url)
    {
        lable.text = "";    //情况显示 
        WWW wwwWeather = new WWW(url);
        while (!wwwWeather.isDone)
        {
            yield return null;
        }
        if (wwwWeather.error == null)
        {
            #region 解析Json字符串，并显示，
            JsonData weatherData = JsonMapper.ToObject(wwwWeather.text);
            lable.text += "查询结果:\t" + weatherData["reason"].ToString() + "\n\n";
            JsonData skData = weatherData["result"]["sk"];
            lable.text += "当前实况天气：" + "\n";
            lable.text += "当前温度:\t" + skData["temp"].ToString() + "\n";
            lable.text += "当前风向:\t" + skData["wind_direction"].ToString() + "\n\n";
            lable.text += "当前风力:\t" + skData["wind_strength"].ToString() + "\n\n";
            lable.text += "当前湿度:\t" + skData["humidity"].ToString() + "\n\n";
            lable.text += "当前时间:\t" + skData["time"].ToString() + "\n\n";

            lable.text += "未来几天天气:" + "\n";
            JsonData futureData = weatherData["result"]["future"];

            for (int i = 0; i < futureData.Count; i++)
            {
                lable.text += "Week:" + "\t" + futureData[i]["week"].ToString() + "\n\n";
                lable.text += "Date:" + "\t" + futureData[i]["date"].ToString() + "\n";
                lable.text += "Temperature:" + futureData[i]["temperature"].ToString() + "\n\n";
                lable.text += "Weather:" + futureData[i]["weather"].ToString() + "\n\n";
                lable.text += "Wind:" + "\t" + futureData[i]["wind"].ToString() + "\n\n";
            }
            #endregion
        }
    }
}