android 代码生成selector drawable

public static StateListDrawable makeSelector(Context context, int idNormal, int idPressed, int idFocused) {    StateListDrawable bg = new StateListDrawable();    Drawable normal = context.getResources().getDrawable(idNormal);    Drawable pressed = context.getResources().getDrawable(idPressed);    Drawable focused = context.getResources().getDrawable(idFocused);    bg.addState(new int[]{android.R.attr.state_pressed,}, pressed);    bg.addState(new int[]{android.R.attr.state_focused}, focused);    bg.addState(new int[]{}, normal);    return bg;}

注意： 1.normal state要在最后add      2.要使用button测试