Drawing a line/path on Google Maps

Question

I\'ve been busy for a long time finding out how to draw a line between two (GPS) points on the map in HelloMapView but with no luck.

Could anyone please tell me how

Answer 1

For those who really only want to draw a simple line - there is indeed also the short short version.

GoogleMap map;
// ... get a map.
// Add a thin red line from London to New York.
Polyline line = map.addPolyline(new PolylineOptions()
    .add(new LatLng(51.5, -0.1), new LatLng(40.7, -74.0))
    .width(5)
    .color(Color.RED));

from https://developers.google.com/maps/documentation/android/reference/com/google/android/gms/maps/model/Polyline

Answer 2

This worked for me. With the method mentioned here I was able to draw polylines on Google Maps V2. I drew a new line whenever the user location got changed, so the the polyline looks like the path followed by user on map.

Source code at. Github: prasang7/eTaxi-Meter

Please ignore other modules of this project related to distance calculation and User Interface if you are not interested in them.

Answer 3

This can be done by using intents too:

  final Intent intent = new Intent(Intent.ACTION_VIEW,
    Uri.parse(
            "http://maps.google.com/maps?" +
            "saddr="+YOUR_START_LONGITUDE+","+YOUR_START_LATITUDE+"&daddr="YOUR_END_LONGITUDE+","+YOUR_END_LATITUDE));
         intent.setClassName(
          "com.google.android.apps.maps",
          "com.google.android.maps.MapsActivity");
   startActivity(intent);

Answer 4

Yes you need to use overlays.

You need to get the MapView's overlays and add your new overlay onto it.

Your class extends Overlay, which is a transparent canvas in which you can draw on it like any other canvas.

You can use mapView.getProjection() to get projection of map view.

...

More info found here: http://blogoscoped.com/archive/2008-12-15-n14.html

Answer 5

just i will find draw with some rectangle in mapview just we want change paint as we like

EmptyOverlay.java

public class EmptyOverlay extends Overlay {
private float x1,y1;
private MapExampleActivity mv = null;
private Overlay overlay = null;

public EmptyOverlay(MapExampleActivity mapV){
    mv = mapV;
}

@Override
public boolean draw(Canvas canvas, MapView mapView, boolean shadow,
        long when) {
    // TODO Auto-generated method stub
    return super.draw(canvas, mapView, shadow, when);
}

@Override
public boolean onTouchEvent(MotionEvent e, MapView mapView) {
    if(mv.isEditMode()){
        if(e.getAction() == MotionEvent.ACTION_DOWN){
            //when user presses the map add a new overlay to the map
            //move events will be catched by newly created overlay
            x1 = y1 = 0;
            x1 = e.getX();
            y1 = e.getY();

            overlay = new MapOverlay(mv, x1, y1);
            mapView.getOverlays().add(overlay);

        }
        if(e.getAction() == MotionEvent.ACTION_MOVE){
        }
        //---when user lifts his finger---
        if (e.getAction() == MotionEvent.ACTION_UP) {                

        }    
        return true;
    }
    return false;
}
}

MapExampleActivity.java

 public class MapExampleActivity extends MapActivity {
private MapView mapView;
private boolean isEditMode = false;
private Button toogle;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    toogle = (Button)findViewById(R.id.toogleMap);        
    toogle.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            toogleEditMode();

        }
    });

    mapView = (MapView)findViewById(R.id.mapview);
    mapView.setBuiltInZoomControls(true); //display zoom controls
    //add one empty overlay acting as a overlay loader. This will catch press events and will add the actual overlays
    mapView.getOverlays().add(new EmptyOverlay(this));
    mapView.postInvalidate();
}
//toogle edit mode for drawing or navigating the map
private void toogleEditMode(){
    isEditMode = !isEditMode;
}

@Override
protected boolean isRouteDisplayed() {
    // TODO Auto-generated method stub
    return false;
}
@Override
protected boolean isLocationDisplayed() {
    return false;
}

public boolean isEditMode(){
    return this.isEditMode;
}

public MapView getMapView(){
    return this.mapView;
}
}

MapOverlay.java

 public class MapOverlay extends Overlay {

private float x1,y1,x2,y2;
private GeoPoint p1=null,p2=null;
private MapExampleActivity mv = null;
private Paint paint = new Paint();
private boolean isUp = false;

//constructor receiving the initial point
public MapOverlay(MapExampleActivity mapV,float x,float y){
    paint.setStrokeWidth(2.0f);
    x1 = x;
    y1 = y;
    mv = mapV;
    p1 = mapV.getMapView().getProjection().fromPixels((int)x1,(int)y1);
}
//override draw method to add our custom drawings
@Override
public boolean draw(Canvas canvas, MapView mapView, boolean shadow,
        long when) {

    if(p1 != null && p2 != null){
        //get the 2 geopoints defining the area and transform them to pixels
        //this way if we move or zoom the map rectangle will follow accordingly
        Point screenPts1 = new Point();
        mapView.getProjection().toPixels(p1, screenPts1);
        Point screenPts2 = new Point();
        mapView.getProjection().toPixels(p2, screenPts2);

        //draw inner rectangle
        paint.setColor(0x4435EF56);
        paint.setStyle(Style.FILL);
        canvas.drawRect(screenPts1.x, screenPts1.y, screenPts2.x, screenPts2.y, paint);
        //draw outline rectangle
        paint.setColor(0x88158923);
        paint.setStyle(Style.STROKE);
        canvas.drawRect(screenPts1.x, screenPts1.y, screenPts2.x, screenPts2.y, paint);
    }
    return true;
}

@Override
public boolean onTouchEvent(MotionEvent e, MapView mapView) {
    if(mv.isEditMode() && !isUp){
        if(e.getAction() == MotionEvent.ACTION_DOWN){
            x1 = y1 = 0;
            x1 = e.getX();
            y1 = e.getY();
            p1 = mapView.getProjection().fromPixels((int)x1,(int)y1);

        }
        //here we constantly change geopoint p2 as we move out finger
        if(e.getAction() == MotionEvent.ACTION_MOVE){
            x2 = e.getX();
            y2 = e.getY();
            p2 = mapView.getProjection().fromPixels((int)x2,(int)y2);

        }
        //---when user lifts his finger---
        if (e.getAction() == MotionEvent.ACTION_UP) {                
            isUp = true;
        }    
        return true;
    }
    return false;
}
 }

see this http://n3vrax.wordpress.com/2011/08/13/drawing-overlays-on-android-map-view/

Answer 6

Try this one:
Add itemizedOverlay class:

public class AndroidGoogleMapsActivity extends MapActivity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Displaying Zooming controls
        MapView mapView = (MapView) findViewById(R.id.mapview);
        mapView.setBuiltInZoomControls(true);


        MapController mc = mapView.getController();
        double lat = Double.parseDouble("48.85827758964043");
        double lon = Double.parseDouble("2.294543981552124");
        GeoPoint geoPoint = new GeoPoint((int)(lat * 1E6), (int)(lon * 1E6));
        mc.animateTo(geoPoint);
        mc.setZoom(15);
        mapView.invalidate(); 


        /**
         * Placing Marker
         * */
        List<Overlay> mapOverlays = mapView.getOverlays();
        Drawable drawable = this.getResources().getDrawable(R.drawable.mark_red);
        AddItemizedOverlay itemizedOverlay = 
             new AddItemizedOverlay(drawable, this);


        OverlayItem overlayitem = new OverlayItem(geoPoint, "Hello", "Sample Overlay item");

        itemizedOverlay.addOverlay(overlayitem);
        mapOverlays.add(itemizedOverlay);

    }

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