How to remove all the polylines from a map

Update

If you want to removes all markers, polylines, polygons, overlays, etc from the map use

mMap.clear(); //it will remove all additional objects from map 

and if you only want to remove all or single polyline, polygon, marker etc see @DiskDev Answer above. In this case you must keep track of every single additional object you add to map

I know this is very old question but I noticed that this is very common need. I found another way and I wanted to share it.

Here is the basic idea:

Polyline polylineFinal;
PolylineOptions polylineOptions;

loop {

    polylineOptions.add( new LatLng( latitude, longitude ) );

}

polylineOptions.width(2);
polylineOptions.color(Color.RED);
polylineOptions.geodesic(true);

polylineFinal = map.addPolyline (polylineOptions);

Map's "addPolyline" method returns a single polyline which contains all the points. When I need to remove the points, I call polylineFinal's "remove" method.

polylineFinal.remove();

Keep track of the Polyline as you add it to the map:

Polyline polyline = this.mMap.addPolyline(new PolylineOptions().....);

Then when you want to remove it:

polyline.remove();

If you have lots of Polylines, just add them to a List as they are put on the map:

List<Polyline> polylines = new ArrayList<Polyline>();

for(....)
{
    polylines.add(this.mMap.addPolyline(new PolylineOptions()....));
}

And when you want to delete:

for(Polyline line : polylines)
{
    line.remove();
}

polylines.clear();

The key is to keep a reference to the Polyline objects and call .remove() on each one.