GetDefaultButtonBackground.java

public static Drawable getDefaultButtonBackground(Context context) {
        int[] attrsButtonStyle = {android.R.attr.buttonStyle};
        TypedArray taButtonStyle = context.getTheme().obtainStyledAttributes(attrsButtonStyle);
        int buttonStyle = taButtonStyle.getResourceId(0, 0);
        taButtonStyle.recycle();

        int[] attrs = {android.R.attr.background};
        TypedArray ta = context.getTheme().obtainStyledAttributes(buttonStyle, attrs);
        Drawable background = ta.getDrawable(0);
        ta.recycle();
        return background;
    }