public void setDrawable (Drawable drawable) {
		if (drawable != null) {
			if (this.drawable == drawable) return;
			if (getPrefWidth() != drawable.getMinWidth() || getPrefHeight() != drawable.getMinHeight()) invalidateHierarchy();
		} else {
			if (getPrefWidth() != 0 || getPrefHeight() != 0) invalidateHierarchy();
		}
		this.drawable = drawable;
	}