获取位置和纬度分别为0.0和0.0

Question

我已经完成了这个tutorial。我遵循那里提到的每一步。我的纬度和经度分别为0.0和0.0。我想通过GPS阅读用户的当前位置。而且，我想为当前用户提供其他活动用户位置。我的项目基于通过GPS系统进行的公交跟踪。请参阅下面的代码。

Dynamic_Map.java：

 public class Dynamic_Map extends
 FragmentActivity {  private GoogleMap googleMap;   GPSTracker gps;     
    @Override   protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.dynamic_map);
                try{
                        gps = new GPSTracker(this);

                  if(gps.canGetLocation()){
                 if(gps.isGPSEnabled){
               double latitudee = gps.getLatitude();
               double longitudee = gps.getLongitude();


               Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + latitudee + "\nLong: " + longitudee, Toast.LENGTH_LONG).show();
                 }else{
                     Toast.makeText(getApplicationContext(), "Your Location is not available bcos gps is
 "+gps.isGPSEnabled,Toast.LENGTH_LONG).show();
                     gps.showSettingsAlert();
                 }
            }else{

             gps.showSettingsAlert();
           }                    initilizeMap();             }       catch(Exception e)      {           e.printStackTrace();        }   }       } 

GPSTracker.java

public class GPSTracker extends Service implements
 LocationListener {     private final Context mContext;     private String
 provider;      boolean isGPSEnabled = false;   
        boolean isNetworkEnabled = false;   
    boolean canGetLocation = false;         Location location;// location
    double latitude;    double longitude;           private static final
 long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10;     private static final long
 MIN_TIME_BW_UPDATES = 1000*60*1;           protected LocationManager locationManager;      public
 GPSTracker(Context context){       this.mContext = context;
        getLocation();      //onLocationChanged(location);
            }
            public Location getLocation(){      try{            LocationManager = (LocationManager)mContext.getSystemService(LOCATION_SERVICE);
            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,
 0, 0, this);



                                    isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
                                isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
                        if(!isGPSEnabled && !isNetworkEnabled){
                            }else{
                this.canGetLocation = true;
                isGPSEnabled =  locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
                //isGPSEnabled = true;
                //First get location from Network Provider
                if(isNetworkEnabled){
                    locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,MIN_TIME_BW_UPDATES,MIN_DISTANCE_CHANGE_FOR_UPDATES,this);
                    Log.d("Network","Network");
                if(locationManager != null){
                        location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                        if(location !=null){
                            System.out.println("Provider " + provider + " has been selected.");
                              onLocationChanged(location);

                }       
                    }                   
                    }}

                    }catch(Exception e){            e.printStackTrace();        }
                return location;    }   @Override   public void onLocationChanged(Location location){
                        latitude = location.getLatitude();      longitude = location.getLongitude();        }       @Override   public void
 onProviderDisabled(String provider){       Toast.makeText(this, "Disabled
 new provider " + provider,
                Toast.LENGTH_SHORT).show();     }       @Override
     public void onProviderEnabled(String provider) {       Toast.makeText(this, "Enabled new provider " + provider,
                Toast.LENGTH_SHORT).show();
     }

     @Override
     public void onStatusChanged(String provider, int status, Bundle extras) {
     }
        @Override
     public IBinder onBind(Intent arg0){
        return null;
     }
        /**
     * Function to get latitude
     * 
     */    public double getLatitude(){
       if(location != null){
           latitude = location.getLatitude();
           Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + latitude, Toast.LENGTH_LONG).show();
       }

       //return latitude;
       return latitude;    }
        /**
     * Function to get longitude
     */    public double getLongitude(){
       if(location !=null){
           longitude = location.getLongitude();
           Toast.makeText(getApplicationContext(), "Your Location is - \nLng: " + longitude, Toast.LENGTH_LONG).show();
       }

       //return longitude;
       return longitude;
           }
        /**
     * Function to check if best network provider
     * @return boolean
     */    public boolean canGetLocation(){
       return this.canGetLocation;    }
        /**
     * Function to show settings alert dialog
     */    public void showSettingsAlert(){
       AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);

       //Setting Dialog Title
       alertDialog.setTitle("GPS is settings");

       //Setting Dialog Message
       alertDialog.setMessage("GPS is not enabled.Do you want to go to settings menu?");

       //On pressing Settings button 
       alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
           public void onClick(DialogInterface dialog,int which){
               Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
               mContext.startActivity(intent);

           }
       });

       //On pressing cancel button
       alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
           public void onClick(DialogInterface dialog,int which){
               dialog.cancel();
           }        
       });     
       //Showing Alert Message
       alertDialog.show();
             }       /**
     * Stop using GPS listener
     * Calling this function will stop using GPS in app
     * 
     */
       public void stopUsingGPS(){
       if(locationManager != null){
           locationManager.removeUpdates(GPSTracker.this);
           }  }   }

我在AndroidManifest.xml文件中包含了必要的权限。需要显示当前位置。

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

请帮帮我。