Google Map V2 地理编码器返回 null

Question

以下是我的谷歌地图 v2 地理编码代码。我从 longclick 监听器上的地图获取纬度和经度。我想解码这个纬度和经度以获得地址。但是我的地址大小总是返回零。怎么回事不知道。

 Log.i("lat long", ": "+arg0.latitude+","+arg0.longitude); 
 Log.i("Geocoder returns", ": "+geocoder.getFromLocation(arg0.latitude,arg0.longitude,1));
               addresses = geocoder.getFromLocation(arg0.latitude,arg0.longitude,1);
               Log.i("Print address array", ": "+addresses.size()+","+addresses); 

Answer 1

 private String getAddress(Double lat, Double lng)
 {

    try 
    {
      Geocoder geocoder = new Geocoder(this, Locale.getDefault());
      List<Address> addresses = geocoder.getFromLocation(lat, lng, 1);
      StringBuilder sb = new StringBuilder();
      if (addresses.size() > 0) 
      {
        Address address = addresses.get(0);

        sb.append(address.getLocality()).append(", ");
        sb.append(address.getCountryName());
      }

     String addressString = sb.toString();
     return addressString;
    } 
    catch (IOException e) 
    {
        return "No Address Found";
    }

}

现在查看函数返回的地址。

Answer 2

根据documentation：

如果未找到匹配项或没有可用的后端服务，则返回 null 或空列表。

所以地理编码器可能无法确定给定坐标的地址。

确保在清单中声明 INTERNET 权限。

<uses-permission android:name="android.permission.INTERNET" />

Answer 3

这是我用的：

package com.exercise.AndroidFromLocation;

import java.io.IOException;
import java.util.List;
import java.util.Locale;

import android.app.Activity;
import android.location.Address;
import android.location.Geocoder;
import android.os.Bundle;
import android.widget.TextView;

public class AndroidFromLocation extends Activity {

double LATITUDE = 37.42233;
double LONGITUDE = -122.083;

   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
       TextView myLatitude = (TextView)findViewById(R.id.mylatitude);
       TextView myLongitude = (TextView)findViewById(R.id.mylongitude);
       TextView myAddress = (TextView)findViewById(R.id.myaddress);

       myLatitude.setText("Latitude: " + String.valueOf(LATITUDE));
       myLongitude.setText("Longitude: " + String.valueOf(LONGITUDE));

       Geocoder geocoder = new Geocoder(this, Locale.ENGLISH);

       try {
  List<Address> addresses = geocoder.getFromLocation(LATITUDE, LONGITUDE, 1);

  if(addresses != null) {
   Address returnedAddress = addresses.get(0);
   StringBuilder strReturnedAddress = new StringBuilder("Address:\n");
   for(int i=0; i<returnedAddress.getMaxAddressLineIndex(); i++) {
    strReturnedAddress.append(returnedAddress.getAddressLine(i)).append("\n");
   }
   myAddress.setText(strReturnedAddress.toString());
  }
  else{
   myAddress.setText("No Address returned!");
  }
 } catch (IOException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
  myAddress.setText("Canont get Address!");
 }

   }
}

Answer 4

android 地理编码器不稳定，大多数时候我也得到了 null。所以，我们改用Google Map API Web Service。这比 IMO 好得多。

下面是我们使用的代码。基本上，只需使用 httpClient 发送 GET 请求，响应为 JSON 格式。

public class GoogleGeocodingService implements GeocodingService {
    private static final Logger LOGGER = LoggerFactory.getInstance().getLogger(GoogleGeocodingService.class);
    private static final String DEFAULT_LANG = "en";
    private HttpClient httpClient;

    /**
     * Get httpClient.
     *
     * @return the httpClient
     */
    public HttpClient getHttpClient() {
        return httpClient;
    }

    /**
     * Set httpClient.
     *
     * @param httpClient
     *            the httpClient to set
     */
    public void setHttpClient(HttpClient httpClient) {
        this.httpClient = httpClient;
    }

    @Override
    public String getSimpleReverseLocation(double latitude, double longitude) throws Exception {
        return getSimpleReverseLocation(latitude, longitude, DEFAULT_LANG);
    }

    @Override
    public String getSimpleReverseLocation(double latitude, double longitude, String language) throws Exception {
        List<BasicNameValuePair> params = new ArrayList<BasicNameValuePair>();
        addParameter(params, "latlng", Double.toString(latitude) + "," + Double.toString(longitude));
        addParameter(params, "language", language);
        addParameter(params, "sensor", "true");
        String response = getContent("http://maps.googleapis.com/maps/api/geocode/json", params);
        try {
            GeocodingResponse r = handleResponse(response, GeocodingResponse.class);
            return r.getShortFormattedAddress();
        } catch (Exception e) {
            LOGGER.error(e.toString());
            return "";
        }
    }

    private static void addParameter(List<BasicNameValuePair> parameters, String key, String value) {
        parameters.add(new BasicNameValuePair(key, value));
    }

    private String getContent(String url, List<BasicNameValuePair> parameters) throws Exception {
        url = HttpClientUtils.createGetUrl(url, parameters);

        //LOGGER.debug("URL: %s", url);
        return HttpClientUtils.getContent(httpClient, new HttpGet(url), new InputStreamToStringConverter());
    }

    private <T> T handleResponse(String response, Class<T> clz) throws IOException {
        //LOGGER.debug("Response: %s", response);
        int first = StringUtils.indexOf(response, '{');
        //LOGGER.debug("first position of '{' = %d", first);
        if (first > 0) {
            response = StringUtils.substring(response, first);
            LOGGER.debug("Response: after clean server side error html from json response: %s", response);
        }
        return JacksonUtils.parse(response, clz);
    }

}