如何擁有一個非常精確的地理位置？

Question

我在android上開發一個檢索用戶位置的應用程序。其實我需要使用最可靠的服務，因爲我需要一個非常精確的位置。

我不知道現在該做什麼，特別是因爲我是初學者。

謝謝你幫我

Answer 1

您將需要用戶LocationManager獲取用戶的經度和緯度。 和GeoCoder獲取地址名稱和其他信息（稱爲反向地理編碼） 請參考以下文檔。

http://developer.android.com/reference/android/location/Geocoder.html

http://developer.android.com/reference/android/location/LocationManager.html

下面的代碼將有助於you.But我建議經過上述鏈接，以獲得正確的認識。

import java.util.List; 
import java.util.Locale; 

import android.app.Activity; 
import android.content.Context; 
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.os.Bundle; 
import android.widget.TextView; 

public class GeoSample extends Activity 
{ 

    @Override 
    public void onCreate(Bundle savedInstanceState) 
    { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.viewmenu); 

     LocationManager locationManager; 
     String context = Context.LOCATION_SERVICE; 
     locationManager = (LocationManager) getSystemService(context); 

     Criteria crta = new Criteria(); 
     crta.setAccuracy(Criteria.ACCURACY_FINE); 
     crta.setAltitudeRequired(false); 
     crta.setBearingRequired(false); 
     crta.setCostAllowed(true); 
     crta.setPowerRequirement(Criteria.POWER_LOW); 
     String provider = locationManager.getBestProvider(crta, true); 

     // String provider = LocationManager.GPS_PROVIDER; 
     Location location = locationManager.getLastKnownLocation(provider); 
     updateWithNewLocation(location); 

     locationManager.requestLocationUpdates(provider, 1000, 0, 
       locationListener); 
    } 

    private final LocationListener locationListener = new LocationListener() 
    { 

     @Override 
     public void onLocationChanged(Location location) 
     { 
      updateWithNewLocation(location); 
     } 

     @Override 
     public void onProviderDisabled(String provider) 
     { 
      updateWithNewLocation(null); 
     } 

     @Override 
     public void onProviderEnabled(String provider) 
     { 
     } 

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

    }; 

    private void updateWithNewLocation(Location location) 
    { 
     String latLong; 
     TextView myLocation; 
     myLocation = (TextView) findViewById(R.id.myLocation); 

     String addressString = "no address found"; 

     if (location != null) 
     { 
      double lat = location.getLatitude(); 
      double lon = location.getLongitude(); 
      latLong = "Lat:" + lat + "\nLong:" + lon; 

      double lattitude = location.getLatitude(); 
      double longitude = location.getLongitude(); 

      Geocoder gc = new Geocoder(this, Locale.getDefault()); 
      try 
      { 
       List<Address> addresses = gc.getFromLocation(lattitude, 
         longitude, 1); 
       StringBuilder sb = new StringBuilder(); 
       if (addresses.size() > 0) 
       { 
        Address address = (Address) addresses.get(0); 
        sb.append(address.getAddressLine(0)).append("\n"); 
        sb.append(address.getLocality()).append("\n"); 
        sb.append(address.getPostalCode()).append("\n"); 
        sb.append(address.getCountryName()); 
       } 
       addressString = sb.toString(); 
      } catch (Exception e) 
      { 
      } 
     } else 
     { 
      latLong = " NO Location Found "; 
     } 
     myLocation.setText("your Current Position is :\n" + latLong + "\n " 
       + addressString); 
    } 
} 

記住GPS提供商將爲您提供準確information.But將需要一些時間 和消耗更多的電池。

希望這會有所幫助。

Answer 2

try { 
      gps_enabled = locManager.isProviderEnabled(LocationManager.GPS_PROVIDER); 
     } catch (Exception ex) { 
     } 
     try { 
      network_enabled = locManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER); 
     } catch (Exception ex) { 
     } 

     if (!gps_enabled && !network_enabled) { 
      // show alert 
     } 
     if (network_enabled) { 
      locManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locListener); 
     } 
     if (gps_enabled) { 
      locManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locListener); 
     }