Android Bitmap 操作

1、转换Drawable 为Bitmap

/** 
      * Bitmap转化为drawable 
      * @param bitmap 
      * @return 
      */  
     public static Drawable bitmap2Drawable(Bitmap bitmap){  
         return new BitmapDrawable(bitmap) ;  
     }  
       
     /** 
      * Drawable 转 bitmap 
      * @param drawable 
      * @return 
      */  
     public static Bitmap drawable2Bitmap(Drawable drawable){  
         if(drawable instanceof BitmapDrawable){  
             return ((BitmapDrawable)drawable).getBitmap() ;  
         }else if(drawable instanceof NinePatchDrawable){  
             Bitmap bitmap = Bitmap  
                     .createBitmap(  
                             drawable.getIntrinsicWidth(),  
                             drawable.getIntrinsicHeight(),  
                             drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888  
                                     : Bitmap.Config.RGB_565);  
             Canvas canvas = new Canvas(bitmap);  
             drawable.setBounds(0, 0, drawable.getIntrinsicWidth(),  
                     drawable.getIntrinsicHeight());  
             drawable.draw(canvas);  
             return bitmap;  
         }else{  
             return null ;  
         }  
    }