有没有搞Android下wifi的朋友，进来聊聊

编写了一个android下的wifi定位程序，连好wifi后发布到真机上运行，结果无法得到经纬度。求大神帮忙看看。  我在真机的设置选项里，已经选上了网络定位选项。代码如下：想实现在log中打印经纬度，并在UI上显示地理信息。 我在运行时，打印的经纬度均为0；也得不到地理信息。
package com.example.wifitest;
import java.io.IOException;
import java.util.List;import android.app.Activity;
import android.os.Bundle;
import android.location.Address;
import android.location.Criteria;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.util.Log;
import android.widget.Toast;public class MainActivity extends Activity {
 //创建位置监听器
    private LocationListener locationListener = new LocationListener(){
        //位置发生改变时调用
        @Override
        public void onLocationChanged(Location location) {
         
            Log.d("Location", "onLocationChanged Latitude" + location.getLatitude());
            Log.d("Location", "onLocationChanged Longitude" + location.getLongitude());
        }        //provider失效时调用
        @Override
        public void onProviderDisabled(String provider) {
            Log.d("Location", "onProviderDisabled");
        }        //provider启用时调用
        @Override
        public void onProviderEnabled(String provider) {
            Log.d("Location", "onProviderEnabled");
        }        //状态改变时调用
        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
            Log.d("Location", "onStatusChanged");
        }
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //获取到LocationManager对象
        LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
     
String currentProvider = locationManager.getProvider(LocationManager.NETWORK_PROVIDER).getName();     
 
       
        Location currentLocation = locationManager.getLastKnownLocation(currentProvider);
        //如果位置信息为null，则请求更新位置信息
        if(currentLocation == null){
            locationManager.requestLocationUpdates(currentProvider, 1, 0, locationListener);
        }
        while(true){
            currentLocation = locationManager.getLastKnownLocation(currentProvider);
            if(currentLocation != null){
                Log.d("Location", "Latitude: " + currentLocation.getLatitude());
                Log.d("Location", "location: " + currentLocation.getLongitude());
                break;
            }else{
                Log.d("Location", "Latitude: " + 0);
                Log.d("Location", "location: " + 0);
            }
            try {
                Thread.sleep(10000);
            } catch (InterruptedException e) {
                 Log.e("Location", e.getMessage());
            }
        }
        
        //解析地址并显示
        Geocoder geoCoder = new Geocoder(this);
        try {
            int latitude = (int) currentLocation.getLatitude();
            int longitude = (int) currentLocation.getLongitude();
            List<Address> list = geoCoder.getFromLocation(latitude, longitude, 2);
            for(int i=0; i<list.size(); i++){
                Address address = list.get(i); 
                Toast.makeText(MainActivity.this, address.getCountryName() + address.getAdminArea() + address.getFeatureName(), Toast.LENGTH_LONG).show();
            }
        } catch (IOException e) {
            Toast.makeText(MainActivity.this,e.getMessage(), Toast.LENGTH_LONG).show();
        }    
      
    }
    }