Android：三角形作为XML可绘制对象

Question

I would like to include a bottom right triangle on the background of each item in a listview.

I can achieve this using nine-patch images:

But, there can be different possible colors, so I would like to do this with XML drawables, so that I can easily add more colors.

My questions are 2:

1) How I can draw triangles as XML drawables ? (I have realized that the triangle is not one of the possible drawing shapes in Android)

2) In case I manage to achieve a triangle drawable, how can I force that drawable to say at the bottom right background ? (with nine-patch images is pretty easy, but I don't know how to do the same with drawables)

Answer 1

1) If there is no need for scaling then you could simply take your ninepatch drawable and recolor it. For example if your base triangle had transparent background and the triangle was white you could do something like this to color it into red:

NinePatch ninePatch;
NinePatchDrawable drawable = new NinePatchDrawable(ninePatch);
drawable.setColorFilter(Color.RED, Mode.MULTIPLY);

2) Solved since you know how to do it with ninepatches