Show boat route in Google Maps MapView - Android

Issue

I currently need to display a boat/cruise ship route in a MapView, something like this

I started coding my version of it, but since every example that I see of water routes are the same I started wondering if there was a "standard" method of doing it. I have been searching for hours and haven't found anything yet, so I decided to ask here.

Here's what I have so far:

Point point2 = new Point();
projection.toPixels(gp2, point2);
paint.setStrokeWidth(5);
paint.setPathEffect(new DashPathEffect(new float[] {8,12}, 5));
paint.setAlpha(defaultColor==Color.parseColor("#6C8715")?200:100);
canvas.drawLine(point.x, point.y, point2.x,point2.y, paint);

It is working and the only thing left to do is adjust the line every time that the user zooms. Is this the way to do it, or there's a standard way of doing it?

Any help is appreciated, thank you.

Solution

If you move your code to an Overlay then you wouldn't have to worry about adjusting the line when the user zooms/pans. Since you probably have more than two points to draw you can also take advantage of the Path class.

import com.google.android.maps.Overlay;

class PathOverlay extends Overlay {

    private void List<GeoPoint>geoPoints;

    public PathOverlay(List<GeoPoint> points) {
        this.geoPoints = geoPoints;
    }   

    public void draw(Canvas canvas, MapView mapView, boolean shadow) {
        super.draw(canvas, mapv, shadow);

        Paint paint = new Paint();
        paint.setStrokeWidth(5);
        paint.setPathEffect(new DashPathEffect(new float[] {8,12}, 5));
        paint.setAlpha(defaultColor==Color.parseColor("#6C8715")?200:100);

        Path path = new Path();
        boolean isFirst = true;
        for (GeoPoint geoPoint : this.geoPoints) {
            Point point = new Point();
            mapView.getProjection().toPixels(geoPoint, point);
            if (isFirst) {
                isFirst = false;
                path.moveTo(point.x, point.y);
            }
            else {
                path.lineTo(point.x,point.y);
            }
        }
        canvas.drawPath(path, paint);
    }
}

Answered By - Nathan Villaescusa