ColorMatrixColorFilter 类

Android的图片资源默认是静态的，单实例；如果两个IM好友的头像一样，最简单的都是用的软件自带头像，有一个在线，一个离线，直接改变头像的灰度，则两个用户的头像都会变灰或者在线，答案是：Drawable.mutate()。

Drawable mDrawable = context.getResources().getDrawable(R.drawable.face_icon);
//Make this drawable mutable.
//A mutable drawable is guaranteed to not share its state with any other drawable.
mDrawable.mutate();
ColorMatrix cm = new ColorMatrix();
cm.setSaturation(0);
ColorMatrixColorFilter cf = new ColorMatrixColorFilter(cm);
mDrawable.setColorFilter(cf);