Android studio farben hinzufügen Wie geht das??

colors.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#3F51B5</color>
    <color name="colorPrimaryDark">#303F9F</color>
    <color name="colorAccent">#FF4081</color>
    <color name="grey">#B8B3B2</color>
</resources>

protected void onDraw(Canvas canvas){
    canvas.drawColor(R.colors.grey);
    canvas.drawBitmap(bmp, 25, 66, null);


}