如何獲取經緯度的城市信息

我正在製作android應用程序。我遇到了一些關於獲取位置的問題。如何獲取經緯度的城市信息

在我的代碼中，我讓我的應用程序獲取GPS的經度和緯度。但是，我仍然無法獲得經緯度的城市名稱。我不知道爲什麼我的代碼會出現異常，即使我的代碼中沒有錯誤的東西。

這裏是我讓城市名稱

ackage org.androidtown.getcurrentlocation; 

import android.Manifest; 
import android.content.ContentResolver; 
import android.content.Context; 
import android.content.DialogInterface; 
import android.content.Intent; 
import android.content.pm.PackageManager; 
import android.location.Address; 
import android.location.Geocoder; 
import android.location.Location; 
import android.location.LocationListener; 
import android.location.LocationManager; 
import android.os.Build; 
import android.provider.Settings; 
import android.support.v4.app.ActivityCompat; 
import android.support.v7.app.AlertDialog; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.View; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.ProgressBar; 
import android.widget.Toast; 

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

public class GetCurrentLocation extends AppCompatActivity implements View.OnClickListener { 
    private LocationManager locationManager = null; 
    private LocationListener locationListener = null; 

    private Button btnGetLocation = null; 
    private EditText editLocation = null; 
    private ProgressBar pb = null; 

    private static final String TAG = "Debug"; 
    private Boolean flag = false; 

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

     pb = (ProgressBar) findViewById(R.id.progressBar1); 
     pb.setVisibility(View.INVISIBLE); 

     editLocation = (EditText) findViewById(R.id.editTextLocation); 

     btnGetLocation = (Button) findViewById(R.id.btnLocation); 
     btnGetLocation.setOnClickListener(this); 

     locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE); 
    } 

    @Override 
    public void onClick(View v) { 
     flag = displayGpsStatus(); 
     if (flag) { 
      Log.v(TAG, "onClick"); 

      editLocation.setText("Please!! move your device to see the changes in coordinates.\nWait.."); 

      pb.setVisibility(View.VISIBLE); 
      locationListener = new MyLocationListener(); 
       if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {return;} 

       locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 5000, 10, locationListener); 

      } 
     else{ 
      alertbox("GPS Status!!", "Your GPS is : OFF"); 
     } 
    } 

    private Boolean displayGpsStatus(){ 
     ContentResolver contentResolver = getBaseContext().getContentResolver(); 
     boolean gpsStatus = Settings.Secure.isLocationProviderEnabled(contentResolver, LocationManager.GPS_PROVIDER); 
     if(gpsStatus){ 
      return true; 
     } 
    else{ 
      return false; 
     } 
    } 

    protected void alertbox(String title, String mymessage){ 
     AlertDialog.Builder builder = new AlertDialog.Builder(this); 
     builder.setMessage("Your Device's GPS is Disable").setCancelable(false).setTitle("**GPS Status**").setPositiveButton("Gps On", new DialogInterface.OnClickListener(){ 
      public void onClick(DialogInterface dialog, int id){ 
       Intent myIntent = new Intent(Settings.ACTION_SECURITY_SETTINGS); 
       startActivity(myIntent); 
       dialog.cancel(); 
      } 
     }).setNegativeButton("Cancel", new DialogInterface.OnClickListener() { 
      @Override 
      public void onClick(DialogInterface dialog, int id) { 
       dialog.cancel(); 
      } 
     }); 

     AlertDialog alert = builder.create(); 
     alert.show(); 
    } 

    private class MyLocationListener implements LocationListener{ 
     @Override 
     public void onLocationChanged(Location loc){ 
      editLocation.setText(""); 
      pb.setVisibility(View.INVISIBLE); 
      Toast.makeText(getBaseContext(), "Location changed : Lat " + loc.getLatitude() +"Lng: "+loc.getLongitude(), 
        Toast.LENGTH_SHORT).show(); 
      String longtitude = "Longtitude: "+loc.getLongitude(); 
      Log.v(TAG, longtitude); 
      String latitude = "Latitude: "+loc.getLatitude(); 
      Log.v(TAG, latitude); 


      String cityName = "default"; 
      Geocoder gcd = new Geocoder(getBaseContext(), Locale.getDefault()); 
      // addresses 
      try{ 
       List<Address> addresses = gcd.getFromLocation(loc.getLatitude(), loc.getLongitude(), 1); 
       if(addresses.size()>0) { 
        System.out.println(addresses.get(0).getLocality()); 
        cityName = addresses.get(0).getLocality(); 
       } 
      }catch(IOException e){ 
       e.printStackTrace(); 
      } 

      String s = longtitude + "\n" + latitude + 
        "\n\nMy Current City is : "+ cityName; 
        editLocation.setText(s); 
     } 

     @Override 
     public void onProviderDisabled(String provider){ 

     } 

     @Override 
     public void onProviderEnabled(String provider){ 

     } 

     @Override 
     public void onStatusChanged(String provider, int status, Bundle extras){ 

     } 



    } 
}

在上面的代碼代碼，這部分代碼主要由經度和緯度來獲得城市的名字。獲得經度和緯度沒有問題。唯一的問題是獲得城市名稱。

String cityName = "default"; 
      Geocoder gcd = new Geocoder(getBaseContext(), Locale.getDefault()); 
      // addresses 
      try{ 
       List<Address> addresses = gcd.getFromLocation(loc.getLatitude(), loc.getLongitude(), 1); 
       if(addresses.size()>0) { 
        System.out.println(addresses.get(0).getLocality()); 
        cityName = addresses.get(0).getLocality(); 
       } 
      }catch(IOException e){ 
       e.printStackTrace(); 
      } 

      String s = longtitude + "\n" + latitude + 
        "\n\nMy Current City is : "+ cityName; 
        editLocation.setText(s); 
     }

謝謝你閱讀我的問題。午夜有一個美好的一天（？）。

來源

2017-06-05 Wongeun Cho

您能否請張貼例外？ – Saurabh7474

例外情況是由以下代碼的地址生成的，沒有任何列表

。這意味着它沒有被初始化。 List

addresses = gcd.getFromLocation（loc.getLatitude（），loc.getLongitude（），1）; –

使用[Google搜索地點API]（https://developers.google.com/places/web-service/search）獲取地址。 –

First thing you shouldn't call getFromLocation from main thread as this method is synchronous and may take a long time to do its work, so you should not call it from the main, user interface (UI) thread of your app. you should use Intent service class. 
Here is code for it: 


public class GetAddressService extends IntentService { 
    // TODO: Rename actions, choose action names that describe tasks that this 
    // IntentService can perform, e.g. ACTION_FETCH_NEW_ITEMS 
    protected ResultReceiver mReceiver; 
    //protected DataEntry.AddressResultReceiver mReceiver; 
    private static final String TAG = "GetAddressService"; 

    public GetAddressService() { 
     super("GetAddressService"); 
    } 


    @Override 
    protected void onHandleIntent(Intent intent) { 
     mReceiver = intent.getParcelableExtra(Constants.RECEIVER); 
     Log.e(TAG,"mReceiver"+mReceiver); 
      Geocoder geocoder = new Geocoder(this, Locale.getDefault()); 
      List<Address> addresses = null; 
       String errorMessage = ""; 
       // Get the location passed to this service through an extra. 
       Location mCurrentLocation = intent.getParcelableExtra(Constants.LOCATION_DATA_EXTRA); 
       try { 
        addresses = geocoder.getFromLocation(mCurrentLocation.getLatitude(), 
          mCurrentLocation.getLongitude(), 1); 

       } catch (IOException e) { 
        errorMessage = "Service error: "; 
        Log.e(TAG, errorMessage, e); 
       } catch (IllegalArgumentException illegalArgumentException) { 
        // Catch invalid latitude or longitude values. 
        errorMessage = "invalid_lat_long_used"; 
        Log.e(TAG, errorMessage + ". " + 
          "Latitude = " + mCurrentLocation.getLatitude() + 
          ", Longitude = " + 
          mCurrentLocation.getLongitude(), illegalArgumentException); 
       } 
       // Handle case where no address was found. 
       if (addresses == null || addresses.size() == 0) { 
        if (errorMessage.isEmpty()) { 
         errorMessage = "no_address_found"; 
         Log.e(TAG, errorMessage); 
        } 
        deliverResultToReceiver(Constants.FAILURE_RESULT,errorMessage); 
       }else { 
        String cityName = addresses.get(0).getLocality(); 
        String countryName = addresses.get(0).getCountryName(); 
        String rLocation = cityName + "," + countryName; 
        Log.e(TAG, "location: " + rLocation); 
        deliverResultToReceiver(Constants.SUCCESS_RESULT,rLocation); 
       } 
    } 

//To deliver the result back to the activity which started the service 

    private void deliverResultToReceiver(int resultCode, String message) { 
     //mReceiver = new ResultReceiver(this); 
     Bundle bundle = new Bundle(); 
     bundle.putString(Constants.RESULT_DATA_KEY, message); 
     mReceiver.send(resultCode, bundle); 
     Log.e(TAG,"Delivering result"+message); 
    } 


} 


//Constant class to store all constants in one place 

public final class Constants { 
    public static final int SUCCESS_RESULT = 0; 
    public static final int FAILURE_RESULT = 1; 
    public static final String PACKAGE_NAME = 
      "your package name"; 
    public static final String RECEIVER = PACKAGE_NAME + ".RECEIVER"; 
    public static final String RESULT_DATA_KEY = PACKAGE_NAME + 
      ".RESULT_DATA_KEY"; 
    public static final String LOCATION_DATA_EXTRA = PACKAGE_NAME + 
      ".LOCATION_DATA_EXTRA"; 

} 


//call this GetAddressService from your activity 

private AddressResultReceiver mResultReceiver; 

private class MyLocationListener implements LocationListener{ 
     @Override 
     public void onLocationChanged(Location loc){ 
     Intent intent = new Intent(this,GetAddressService.class); 
     intent.putExtra(Constants.RECEIVER,mResultReceiver); 
     intent.putExtra(Constants.LOCATION_DATA_EXTRA,loc); 
     startService(intent); 
     } 



//class to receive the address back from the service 
class AddressResultReceiver extends ResultReceiver{ 

     /** 
     * Create a new ResultReceive to receive results. Your 
     * {@link #onReceiveResult} method will be called from the thread running 
     * <var>handler</var> if given, or from an arbitrary thread if null. 
     * 
     * @param handler 
     */ 
     public AddressResultReceiver(Handler handler) { 
      super(handler); 
     } 

     @Override 
     protected void onReceiveResult(int resultCode, Bundle resultData) { 
      super.onReceiveResult(resultCode, resultData); 
      mAddressOutput = resultData.getString(Constants.RESULT_DATA_KEY); 
      Log.e(TAG,"Address is:"+mAddressOutput); 
     } 
    }

來源

2017-06-05 09:17:07 sumit

我想我的參數'Location loc'正在獲取它被調用的位置值。我可以知道Location值是初始化的，因爲loc.getLongitude（）和loc.getLatitude正在工作。謝謝您的回答。 –

對不起，我不明白你在這裏想告訴你什麼。這不是你的問題，你有拉特/ lng，但你不能從那裏檢索城市名稱？ – sumit

這是正確的，但我不知道什麼問題是.. –

如何獲取經緯度的城市信息

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