Custom Widget using LinearLayout not getting onDraw()

I'm creating a custom widget by extending LinearLayout:

public class MyWidget extends LinearLayout {
    private static Paint PAINT = new Paint(Paint.ANTI_ALIAS_FLAG);
    static {
        PAINT.setColor(Color.RED);
    }

    public MyWidget(Context context) {
        this(context, null);
    }

    public MyWidget(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawCircle(canvas.getWidth() / 2, canvas.getHeight()/2, canvas.getWidth()/2, PAINT);
        // never gets called :-(
    }
    
    @Override
    protected void dispatchDraw(Canvas canvas) {
        super.dispatchDraw(canvas);
        // this gets called, but with a canvas sized after the padding.
    }
}

I can add children just fine, but I'm never getting my custom onDraw() being called. dispatchDraw() gets called, but that seems to have a different canvas (the one that's within the padding. I need to draw on the whole layout area). Is there some flag that needs to get set to get onDraw() called for the layout?

You need to call setWillNotDraw(false) in your constructor.

Because by default a layout does not need to draw, so an optimization is to not call is draw method. By calling setWillNotDraw(false) you tell the UI toolkit that you want to draw.