用wheelview实现的省市区三级联动

【实例截图】

【核心代码】

package com.example.wheel_province;

import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;

import kankan.wheel.widget.OnWheelChangedListener;
import kankan.wheel.widget.WheelView;
import kankan.wheel.widget.adapters.ArrayWheelAdapter;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

/**
 * 
 * @author zhy
 * 
 */
public class CitiesActivity extends Activity implements OnWheelChangedListener
{
	/**
	 * 把全国的省市区的信息以json的格式保存，解析完成后赋值为null
	 */
	private JSONObject mJsonObj;
	/**
	 * 省的WheelView控件
	 */
	private WheelView mProvince;
	/**
	 * 市的WheelView控件
	 */
	private WheelView mCity;
	/**
	 * 区的WheelView控件
	 */
	private WheelView mArea;

	/**
	 * 所有省
	 */
	private String[] mProvinceDatas;
	/**
	 * key - 省 value - 市s
	 */
	private Map<String, String[]> mCitisDatasMap = new HashMap<String, String[]>();
	/**
	 * key - 市 values - 区s
	 */
	private Map<String, String[]> mAreaDatasMap = new HashMap<String, String[]>();

	/**
	 * 当前省的名称
	 */
	private String mCurrentProviceName;
	/**
	 * 当前市的名称
	 */
	private String mCurrentCityName;
	/**
	 * 当前区的名称
	 */
	private String mCurrentAreaName ="";

	@Override
	protected void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);
		setContentView(R.layout.citys);

		initJsonData();

		mProvince = (WheelView) findViewById(R.id.id_province);
		mCity = (WheelView) findViewById(R.id.id_city);
		mArea = (WheelView) findViewById(R.id.id_area);

		initDatas();

		mProvince.setViewAdapter(new ArrayWheelAdapter<String>(this, mProvinceDatas));
		// 添加change事件
		mProvince.addChangingListener(this);
		// 添加change事件
		mCity.addChangingListener(this);
		// 添加change事件
		mArea.addChangingListener(this);

		mProvince.setVisibleItems(5);
		mCity.setVisibleItems(5);
		mArea.setVisibleItems(5);
		updateCities();
		updateAreas();

	}

	/**
	 * 根据当前的市，更新区WheelView的信息
	 */
	private void updateAreas()
	{
		int pCurrent = mCity.getCurrentItem();
		mCurrentCityName = mCitisDatasMap.get(mCurrentProviceName)[pCurrent];
		String[] areas = mAreaDatasMap.get(mCurrentCityName);

		if (areas == null)
		{
			areas = new String[] { "" };
		}
		mArea.setViewAdapter(new ArrayWheelAdapter<String>(this, areas));
		mArea.setCurrentItem(0);
	}

	/**
	 * 根据当前的省，更新市WheelView的信息
	 */
	private void updateCities()
	{
		int pCurrent = mProvince.getCurrentItem();
		mCurrentProviceName = mProvinceDatas[pCurrent];
		String[] cities = mCitisDatasMap.get(mCurrentProviceName);
		if (cities == null)
		{
			cities = new String[] { "" };
		}
		mCity.setViewAdapter(new ArrayWheelAdapter<String>(this, cities));
		mCity.setCurrentItem(0);
		updateAreas();
	}

	/**
	 * 解析整个Json对象，完成后释放Json对象的内存
	 */
	private void initDatas()
	{
		try
		{
			JSONArray jsonArray = mJsonObj.getJSONArray("citylist");
			mProvinceDatas = new String[jsonArray.length()];
			for (int i = 0; i < jsonArray.length(); i  )
			{
				JSONObject jsonP = jsonArray.getJSONObject(i);// 每个省的json对象
				String province = jsonP.getString("p");// 省名字

				mProvinceDatas[i] = province;

				JSONArray jsonCs = null;
				try
				{
					/**
					 * Throws JSONException if the mapping doesn't exist or is
					 * not a JSONArray.
					 */
					jsonCs = jsonP.getJSONArray("c");
				} catch (Exception e1)
				{
					continue;
				}
				String[] mCitiesDatas = new String[jsonCs.length()];
				for (int j = 0; j < jsonCs.length(); j  )
				{
					JSONObject jsonCity = jsonCs.getJSONObject(j);
					String city = jsonCity.getString("n");// 市名字
					mCitiesDatas[j] = city;
					JSONArray jsonAreas = null;
					try
					{
						/**
						 * Throws JSONException if the mapping doesn't exist or
						 * is not a JSONArray.
						 */
						jsonAreas = jsonCity.getJSONArray("a");
					} catch (Exception e)
					{
						continue;
					}

					String[] mAreasDatas = new String[jsonAreas.length()];// 当前市的所有区
					for (int k = 0; k < jsonAreas.length(); k  )
					{
						String area = jsonAreas.getJSONObject(k).getString("s");// 区域的名称
						mAreasDatas[k] = area;
					}
					mAreaDatasMap.put(city, mAreasDatas);
				}

				mCitisDatasMap.put(province, mCitiesDatas);
			}

		} catch (JSONException e)
		{
			e.printStackTrace();
		}
		mJsonObj = null;
	}

	/**
	 * 从assert文件夹中读取省市区的json文件，然后转化为json对象
	 */
	private void initJsonData()
	{
		try
		{
			StringBuffer sb = new StringBuffer();
			InputStream is = getAssets().open("city.json");
			int len = -1;
			byte[] buf = new byte[1024];
			while ((len = is.read(buf)) != -1)
			{
				sb.append(new String(buf, 0, len, "gbk"));
			}
			is.close();
			mJsonObj = new JSONObject(sb.toString());
		} catch (IOException e)
		{
			e.printStackTrace();
		} catch (JSONException e)
		{
			e.printStackTrace();
		}
	}

	/**
	 * change事件的处理
	 */
	@Override
	public void onChanged(WheelView wheel, int oldValue, int newValue)
	{
		if (wheel == mProvince)
		{
			updateCities();
		} else if (wheel == mCity)
		{
			updateAreas();
		} else if (wheel == mArea)
		{
			mCurrentAreaName = mAreaDatasMap.get(mCurrentCityName)[newValue];
		}
	}

	public void showChoose(View view)
	{
		Toast.makeText(this, mCurrentProviceName   mCurrentCityName   mCurrentAreaName, 1).show();
	}
}