トーストが動作しない

Question

私はGoogleマップを使用していますが、トーストが機能しません。誰でも私のコードで間違ったことを知らせてくれますか？

public class GPSLocatorActivity extends MapActivity { 
    Context mContext = this; 

今、毎回あなたはトーストの使用を作りたい：事前に

おかげ

import com.google.android.maps.MapActivity; 
import com.google.android.maps.MapView; 
import com.google.android.maps.MapController; 
import com.google.android.maps.GeoPoint; 
import android.content.Context; 
import android.location.Location; 
import android.location.LocationListener; 
import android.location.LocationManager; 

import android.location.Geocoder; 
import android.location.Address; 

import com.google.android.maps.Overlay; 
import android.graphics.Canvas; 
import android.graphics.Point; 
import android.graphics.Bitmap; 
import android.graphics.BitmapFactory; 

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

import android.os.Bundle; 
import android.view.MotionEvent; 
import android.widget.Toast; 

public class GPSLocatorActivity extends MapActivity { 
    private MapView mapView; 
    private MapController mapController; 

    private LocationManager locationManager; 
    private LocationListener locationListener; 

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

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

     locationListener = new GPSLocationListener(); 

     locationManager.requestLocationUpdates(
      LocationManager.GPS_PROVIDER, 
      0, 
      0, 
      locationListener); 

     mapView = (MapView) findViewById(R.id.mapView); 


     // enable Street view by default 
     // mapView.setStreetView(true); 

     // enable to show Satellite view 
     mapView.setSatellite(true); 

     // enable to show Traffic on map 
     // mapView.setTraffic(true); 
     mapView.setBuiltInZoomControls(true); 

     mapController = mapView.getController(); 
     mapController.setZoom(17); 
     mapView.invalidate(); 

    } 

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

    private class GPSLocationListener implements LocationListener 
    { 
     @Override 
     public void onLocationChanged(Location location) { 
      if (location != null) { 
       GeoPoint point = new GeoPoint(
         (int) (location.getLatitude() * 1E6), 
         (int) (location.getLongitude() * 1E6)); 
       /* 
       //Toast.makeText(getBaseContext(), 
         Toast.makeText(GPSLocatorActivity.this, 
         "Latitude: " + location.getLatitude() + 
         " Longitude: " + location.getLongitude(), 
         Toast.LENGTH_LONG).show(); 
         */ 
       //mapController.setZoom(17);    
       mapController.animateTo(point); 
       mapController.setZoom(17); 

      // add marker 
       MapOverlay mapOverlay = new MapOverlay(); 
       mapOverlay.setPointToDraw(point); 
       List<Overlay> listOfOverlays = mapView.getOverlays(); 
       listOfOverlays.clear(); 
       listOfOverlays.add(mapOverlay); 

       String address = ConvertPointToLocation(point); 
       Toast.makeText(getBaseContext(), address, Toast.LENGTH_SHORT).show(); 

       mapView.invalidate(); 
      } 
     } 

     public String ConvertPointToLocation(GeoPoint point) { 
      String address = ""; 
      Geocoder geoCoder = new Geocoder(
        getBaseContext(), Locale.getDefault()); 
      try { 
       List<Address> addresses = geoCoder.getFromLocation(
        point.getLatitudeE6()/1E6, 
        point.getLongitudeE6()/1E6, 1); 

       if (addresses.size() > 0) { 
        for (int index = 0; index < addresses.get(0).getMaxAddressLineIndex(); index++) 
         address += addresses.get(0).getAddressLine(index) + " "; 
       } 
      } 
      catch (IOException e) {     
       e.printStackTrace(); 
      } 

      return address; 
     } 

     @Override 
     public void onProviderDisabled(String provider) { 
     } 

     @Override 
     public void onProviderEnabled(String provider) { 
     } 

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

    class MapOverlay extends Overlay 
    { 
     private GeoPoint pointToDraw; 

     public void setPointToDraw(GeoPoint point) { 
      pointToDraw = point; 
     } 

     public GeoPoint getPointToDraw() { 
      return pointToDraw; 
     } 


     @Override 
     public boolean onTouchEvent(MotionEvent e, MapView mapView) { 
      // TODO Auto-generated method stub 
     return super.onTouchEvent(e, mapView); 
      //mapView.invalidate(); 
      //return false; 

     } 

     @Override 
     public boolean onTap(GeoPoint p, MapView mapView) { 
      // TODO Auto-generated method stub 
      //mapView.invalidate(); 
      return super.onTap(p, mapView); 
     } 

     @Override 
     public boolean draw(Canvas canvas, MapView mapView, boolean shadow, long when) { 
      super.draw(canvas, mapView, shadow);     

      // convert point to pixels 
      Point screenPts = new Point(); 
      mapView.getProjection().toPixels(pointToDraw, screenPts); 

      // add marker 
      Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.red); 
      canvas.drawBitmap(bmp, screenPts.x, screenPts.y - 24, null); // 24 is the height of image   
      return true; 
     } 

    } 
} 

Answer 1

Toast.makeText(GPSLocatorActivity.this, 
         "Latitude: " + location.getLatitude() + 
         " Longitude: " + location.getLongitude(), 
         Toast.LENGTH_LONG).show(); 

は

Answer 2

が最初にこれを追加...これを試してみてください

Toast.makeText(mContext, "some_string", Toast.LENGTH_LONG).show(); 

Answer 3

Toast toast=Toast.makeText(                        
       GPSLocatorActivity.this, 
       "Latitude: " + location.getLatitude() + 
       " Longitude: " + location.getLongitude(), 
       Toast.LENGTH_LONG); 
toast.show(); 

Answer 4

runOnUiThread(new Runnable() { 
    @Override 
    public void run() { 
     Toast.makeText(context, "msg", Toast.LENGTH_SHORT).show(); 
    } 
});