圖片置灰

public void setImageBlack(){

Drawable mDrawable = getResources().getDrawable(R.drawable.ic_launcher);    
//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);  
layout1.setBackgroundDrawable(mDrawable);
}