How to overload "shape" class into xml?

Question

I have this xml drawable. But unfortunately there is a crash when this xml is loaded... due to my shape class "ExtOvalShape":

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item>

        <com.xxx.ui.widget.drawable.shapes.ExtOvalShape android:state_selected="true">
            <solid android:color="@color/theme_accent_1" />
            <stroke android:width="1dp" android:color="@color/background_4" />
            <size android:height="@dimen/part_number_value" android:width="@dimen/part_number_value" />
        </com.xxx.ui.widget.drawable.shapes.ExtOvalShape>

        <com.xxx.ui.widget.drawable.shapes.ExtOvalShape android:state_selected="false">
            <solid android:color="@android:color/transparent" />
            <stroke android:width="1dp" android:color="@color/background_4" />
            <size android:height="@dimen/part_number_value" android:width="@dimen/part_number_value" />
        </com.xxx.ui.widget.drawable.shapes.ExtOvalShape>

    </item>
</selector>

How to overload a shape into a drawable xml?

For information my class (it's just to test):

public class ExtOvalShape extends OvalShape {

    @Override
    public void draw(Canvas canvas, Paint paint) {          
        super.draw(canvas, paint);
    }
}

Answer 1

As far as I know it is not possible to use custom XML elements or extend in any way the existing ones in Android drawable files. You have to stick with the <shape> tag.

What you can do instead is applying programmatically your custom shape, something like:

ExtOvalDrawable ovalDrawable = new ExtOvalDrawable();
view.setBackground(ovalDrawable);