I recently started learning Android coding as a hobby, and I wanted to create a program that could locate and track a user's location using Google Maps.
The software can follow their movements after it gets a GPS lock by plotting a path using an overlay class.
Similar open-source programs, like My tracks, have been seen by me, but they are currently too complex for me to use.
I'd want to design an application that looks like this in theory.
Here is my code below without the imports.
What I'm trying to do is create an array of geopoints. Every time the location changes a new geopoint is created. I then try to use a for loop to iterate through each geopoint and draw a path between them.
public class Tracking extends MapActivity implements LocationListener {
LocationManager locman;
LocationListener loclis;
Location Location;
private MapView map;
List<GeoPoint> geoPointsArray = new ArrayList<GeoPoint>();
private MapController controller;
String provider = LocationManager.GPS_PROVIDER;
double lat;
double lon;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.map);
initMapView();
initMyLocation();
locman = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
// locman.requestLocationUpdates(provider,60000, 100,loclis);
// Location = locman.getLastKnownLocation(provider);
}
/** Find and initialize the map view. */
private void initMapView() {
map = (MapView) findViewById(R.id.map);
controller = map.getController();
map.setSatellite(false);
map.setBuiltInZoomControls(true);
}
/** Find Current Position on Map. */
private void initMyLocation() {
final MyLocationOverlay overlay = new MyLocationOverlay(this, map);
overlay.enableMyLocation();
overlay.enableCompass(); // does not work in emulator
overlay.runOnFirstFix(new Runnable() {
public void run() {
// Zoom in to current location
controller.setZoom(24);
controller.animateTo(overlay.getMyLocation());
}
});
map.getOverlays().add(overlay);
}
@Override
public void onLocationChanged(Location location) {
if (Location != null) {
lat = Location.getLatitude();
lon = Location.getLongitude();
GeoPoint New_geopoint = new GeoPoint((int) (lat * 1e6),
(int) (lon * 1e6));
controller.animateTo(New_geopoint);
}
}
class MyOverlay extends Overlay {
public MyOverlay() {
}
public void draw(Canvas canvas, MapView mapv, boolean shadow) {
super.draw(canvas, mapv, shadow);
Projection projection = map.getProjection();
Path p = new Path();
for (int i = 0; i < geoPointsArray.size(); i++) {
if (i == geoPointsArray.size() - 1) {
break;
}
Point from = new Point();
Point to = new Point();
projection.toPixels(geoPointsArray.get(i), from);
projection.toPixels(geoPointsArray.get(i + 1), to);
p.moveTo(from.x, from.y);
p.lineTo(to.x, to.y);
}
Paint mPaint = new Paint();
mPaint.setStyle(Style.STROKE);
mPaint.setColor(0xFFFF0000);
mPaint.setAntiAlias(true);
canvas.drawPath(p, mPaint);
super.draw(canvas, map, shadow);
}
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
}
The application runs fine without errors but there is no path drawn, the location dot just moves as i move.
Any help would be greatly appreciated Thanks.
