Google Maps API v2 Android add shape drawable as marker

Question

I've been trying to add a shape drawable as the marker icon for a marker I want to add on the map.

shape looks like this (res/drawable/blue_circle.xml):

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval" >
    <size
        android:width="15dp"
        android:height="15dp" />
    <solid
        android:color="@color/Blue" />
</shape>

and I try to add the marker like this:

markerOptions.icon(BitmapDescriptorFactory.fromResource(R.drawable.blue_circle));

Apparently I get a NullPointer exception.

Must the marker icon be a bitmap? Am I allowed to add shapes drawables as marker icons? And if yes what am I doing wrong?

Answer 1

Create a drawable for your marker (res/drawable/map_dot_red.xml):

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval" >

    <gradient
        android:angle="90"
        android:endColor="#f58383"
        android:startColor="#ee6464" />

    <stroke
        android:width="1dp"
        android:color="#a13939" />

</shape>

Create a bitmap from the drawable:

int px = getResources().getDimensionPixelSize(R.dimen.map_dot_marker_size);
mDotMarkerBitmap = Bitmap.createBitmap(px, px, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(mDotMarkerBitmap);
Drawable shape = getResources().getDrawable(R.drawable.map_dot_red);
shape.setBounds(0, 0, mDotMarkerBitmap.getWidth(), mDotMarkerBitmap.getHeight());
shape.draw(canvas);

Create your marker, using the bitmap:

Marker marker = mMap.addMarker(new MarkerOptions()
    .position(point)
    .anchor(.5f, .5f)
    .icon(BitmapDescriptorFactory.fromBitmap(mDotMarkerBitmap)));

Set the size of your marker in dimens (res/values/dimens.xml):

<resources>
    <dimen name="map_dot_marker_size">12dp</dimen>
</resources>