Android 离线用户的灰色头像处理

Android 离线用户的灰色头像处理

主要涉及两个技术点：

1、图标加灰色过滤；

2、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()。

代码如下：

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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); 
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);

OVER！