Hello guys,
i have written the code to find the GPS location , it was working
fine. later i have added one class for overlays but now its giving me
nullpointer exception on populate function.
the code is below
***************************************
package com.spsoft.lbs.gps;
import java.util.ArrayList;
import java.util.List;
import android.app.AlertDialog;
import android.content.Context;
import android.content.Intent;
import android.graphics.drawable.Drawable;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.Toast;
import com.google.android.maps.GeoPoint;
import com.google.android.maps.ItemizedOverlay;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapController;
import com.google.android.maps.MapView;
import com.google.android.maps.Overlay;
import com.google.android.maps.OverlayItem;
public class GPSMapActivity extends MapActivity {
private LocationManager lm;
private LocationListener locationListener;
private MapView mapView;
private MapController mc;
double lat;
double lan;
final long E6 = 1000000;
private GeoPoint p;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.gps);
// ---use the LocationManager class to obtain GPS locations---
lm = (LocationManager)
getSystemService(Context.LOCATION_SERVICE);
locationListener = new MyLocationListener();
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 200,
200,
locationListener);
Log
.v(getClass().getName(),
"*********************************************after time
interval");
mapView = (MapView) findViewById(R.id.mapview1);
List<Overlay> mapOverlays = mapView.getOverlays();
Drawable drawable =
this.getResources().getDrawable(R.drawable.icon);
HelloItemizedOverlay itemizedoverlay = new HelloItemizedOverlay(
drawable);
OverlayItem overlayitem = new OverlayItem(p, "Hi!", "I am
here!");
itemizedoverlay.addOverlay(overlayitem);
mapOverlays.add(itemizedoverlay);
mc = mapView.getController();
}
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
private class MyLocationListener implements LocationListener {
public void onLocationChanged(Location loc) {
// TODO Auto-generated method stub
if (loc != null) {
Toast.makeText(
getBaseContext(),
"Location changed : Lat: " +
loc.getLatitude()
+ " Lng: " +
loc.getLongitude(),
Toast.LENGTH_SHORT).show();
GeoPoint p = new GeoPoint((int)
(loc.getLatitude() * 1E6),
(int) (loc.getLongitude() *
1E6));
mc.animateTo(p);
mc.setZoom(16);
mapView.invalidate();
Log.i("the values in GPS class are:", "lat:"
+ loc.getLatitude() + "lan:" +
loc.getLongitude());
}
}
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
public void onStatusChanged(String provider, int status, Bundle
extras) {
// TODO Auto-generated method stub
}
}
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu, menu);
return true;
}
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.mapview:
performToggleMap();
break;
case R.id.satelliteview:
performToggleSatellite();
break;
case R.id.trafficview:
performToggleTraffic();
break;
case R.id.findlocation:
Intent intent = new Intent(GPSMapActivity.this,
SearchActivity.class);
intent.putExtra("lat", lat);
intent.putExtra("lan", lan);
Log.i("the values in find button click are:", "lat:" +
lat + "lan:"
+ lan);
startActivity(intent);
break;
}
return true;
}
public boolean performToggleSatellite() {
// Switch on the satellite images
mapView.setSatellite(true);
return true;
}
public boolean performToggleTraffic() {
// Switch on traffic overlays
mapView.setTraffic(true);
Toast.makeText(getBaseContext(),
"Traffic info not available for this location ",
Toast.LENGTH_SHORT).show();
return true;
}
public boolean performToggleMap() {
// Switch on map overlays
mapView.setSatellite(false);
return true;
}
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
}
@Override
protected void onRestart() {
// TODO Auto-generated method stub
super.onRestart();
}
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
}
private class HelloItemizedOverlay extends ItemizedOverlay {
private ArrayList<OverlayItem> mOverlays = new
ArrayList<OverlayItem>();
Context mContext;
public HelloItemizedOverlay(Drawable defaultMarker) {
super(boundCenterBottom(defaultMarker));
}
public void addOverlay(OverlayItem overlay) {
mOverlays.add(overlay);
populate();
}
@Override
protected OverlayItem createItem(int i) {
// TODO Auto-generated method stub
return mOverlays.get(i);
}
@Override
public int size() {
// TODO Auto-generated method stub
return mOverlays.size();
}
public HelloItemizedOverlay(Drawable defaultMarker, Context
context)
{
super(defaultMarker);
mContext = context;
}
@Override
protected boolean onTap(int index) {
OverlayItem item = mOverlays.get(index);
AlertDialog.Builder dialog = new AlertDialog.Builder(
GPSMapActivity.this);
dialog.setTitle(item.getTitle());
dialog.setMessage(item.getSnippet());
dialog.show();
return true;
}
}
}
*****************************************
please solve my issues
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