如何在單擊刷新菜單按鈕後強制更新位置？

Question

我只是想知道是否有可能強制更新位置以獲得移動設備的位置，一旦我點擊菜單中的刷新項目。

下面是我在論壇中找到的代碼，我想添加一個新功能。

import android.os.Bundle; 

import com.google.android.maps.GeoPoint; 
import com.google.android.maps.MapActivity; 
import com.google.android.maps.MapController; 
import com.google.android.maps.MapView; 

import com.google.android.maps.OverlayItem; 

import android.graphics.drawable.Drawable; 
import android.location.Location; 
import android.location.LocationListener; 
import android.location.LocationManager; 
import android.util.Log; 
import android.view.KeyEvent; 
import android.view.Menu; 
import android.view.MenuInflater; 
import android.view.MenuItem; 
import android.widget.Toast; 

public class MapLocator extends MapActivity implements LocationListener { 
    /** Called when the activity is first created. */ 

    private MapView mapView; 
    private LocationManager lm; 
    private MapController mc; 
    private double lat = 0; 
    private double lng = 0; 

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

    mapView = (MapView) this.findViewById(R.id.mapView); 
    mapView.setBuiltInZoomControls(true); 

    mc = mapView.getController(); 
    mc.setZoom(14); 


    int FIVE_MINUTES = 5 /*Minutes*/ * 60 /*sec per min*/ * 1000 /*ms per sec*/; 
    lm = (LocationManager) this.getSystemService(LOCATION_SERVICE); 
    lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, FIVE_MINUTES, 0, this); 
    lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, FIVE_MINUTES, 0, this); 


    Drawable drawable= this.getResources().getDrawable(R.drawable.loc_seven); 
    ListItimizedOverlay itemizedoverlay = new ListItimizedOverlay(drawable); 
    GeoPoint p = new GeoPoint(33000000,84000000); 
    OverlayItem overlayitem = new OverlayItem(p, "Hello from", "Tahiti"); 
    itemizedoverlay.addOverlayItem(overlayitem); 
    mapView.getOverlays().add(itemizedoverlay); 

} 

@Override 
protected boolean isRouteDisplayed() 
{ 
return false; 
} 

@Override 
public boolean onKeyDown(int keyCode, KeyEvent event) 
{ 
    if (keyCode == KeyEvent.KEYCODE_S) 
    { 
     mapView.setSatellite(!mapView.isSatellite()); 
     return true; 
    } 
return super.onKeyDown(keyCode, event); 
} 

@Override 
public void onLocationChanged(Location location) 
{ 
    Log.d("msg","1"); 

    lat = location.getLatitude(); 
    lng = location.getLongitude(); 
     Toast.makeText(
       getBaseContext(), 
       "Location change to : Latitude = " + lat + " Longitude = " 
        + lng, Toast.LENGTH_SHORT).show(); 
    GeoPoint p = new GeoPoint((int) (lat * 1E6), (int) (lng * 1E6)); 
    mc.animateTo(p); 
    mc.setCenter(p); 
    mc.setZoom(14); 
    Drawable drawable= this.getResources().getDrawable(R.drawable.loc_seven); 
    ListItimizedOverlay itemizedoverlay = new ListItimizedOverlay(drawable); 
    OverlayItem overlayitem = new OverlayItem(p, "", ""); 
    itemizedoverlay= (ListItimizedOverlay) mapView.getOverlays().get(0); 
    itemizedoverlay.clear(); 
    itemizedoverlay.addOverlayItem(overlayitem); 
    mapView.getOverlays().add(itemizedoverlay); 

} 

@Override 
public void onProviderDisabled(String provider) 
{ 
} 

@Override 
public void onProviderEnabled(String provider) 
{ 
} 

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


    //Menu with 2 items Refresh and exit 

    public boolean onCreateOptionsMenu(Menu menu2) { 


     MenuInflater inflater = getMenuInflater(); 

     inflater.inflate(R.layout.menumap, menu2); 

     return true; 
    } 


     public boolean onOptionsItemSelected(MenuItem item) { 


      switch (item.getItemId()) { 
      case R.id.refresh: 
       /* 
--------------------------------------------------------------------------------------- 
code to add in order to refrech the location and position the mobile 
on the map using the drawable in the itemizedoverlay. I have tried this : 
    lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this); 
    lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, this); 
and nothing is changed i still see the old position on the map 

and I have tested the app on a sony Ericsson Xperia x10. 

I am using google API 10 if this might help. 



------------------------------------------------------------------------------------------ 
*/ 

       return true; 

      case R.id.exit: 

       finish(); 
       return true; 
     } 
     return false;} 





} 

任何人都可以幫助我嗎？

Answer 1

此代碼應該做的伎倆：

 lm.requestSingleUpdate(LocationManager.GPS_PROVIDER, this, null); 
     Location loc = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER); 
     lat = loc.getLatitude(); 
     lng = loc.getLongitude();