Android毛玻璃背景效果简单实现代码

/**
 * 设置毛玻璃背景
 * 背景图片 Bitmap
 */
private void setBlurBackground(Bitmap bmp)
{
  final Bitmap blurBmp = BlurUtil.fastblur(ParentCircleInfoActivity.this, bmp, 10);//0-25，表示模糊值
  final Drawable drawable = ImageUtil.getDrawable(this,blurBmp);//将bitmap类型图片 转为 Drawable类型
  mRLHead.post(new Runnable() //调用UI线程
  {
    @Override
    public void run()
    {
      mRLHead.setBackgroundDrawable(drawable);
    }
  });
}
bitmap 转 drawable:
/**
 * bitmap -> drawable
 * @param context
 * @param bm
 * @return
 */
public static Drawable getDrawable(Context context, Bitmap bm){
  BitmapDrawable bd= new BitmapDrawable(context.getResources(),bm);
  return bd;
}
使用到的工具类：
public class BlurUtil 
{ 
  @SuppressLint("NewApi")
  public static Bitmap fastblur(Context context, Bitmap sentBitmap, int radius) 
  { 
   if (VERSION.SDK_INT > 16) 
   {    
     Bitmap bitmap = sentBitmap.copy(sentBitmap.getConfig(), true); 
     final RenderScript rs = RenderScript.create(context);
     final Allocation input = Allocation.createFromBitmap(rs,sentBitmap, Allocation.MipmapControl.MIPMAP_NONE,Allocation.USAGE_SCRIPT);
     final Allocation output = Allocation.createTyped(rs,input.getType());
     final ScriptIntrinsicBlur script = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
     script.setRadius(radius);/* e.g. 3.f */
     script.setInput(input);
     script.forEach(output);     
     output.copyTo(bitmap);    
     return bitmap;  
   }   
   Bitmap bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);
    if (radius < 1) 
    {
      return (null);
    }
    int w = bitmap.getWidth();
    int h = bitmap.getHeight();
    int[] pix = new int[w * h];
    Log.e("pix", w + " " + h + " " + pix.length);
    bitmap.getPixels(pix, 0, w, 0, 0, w, h);
    int wm = w - 1;
    int hm = h - 1;
    int wh = w * h;
    int div = radius + radius + 1;
    int r[] = new int[wh];
    int g[] = new int[wh];
    int b[] = new int[wh];
    int rsum, gsum, bsum, x, y, i, p, yp, yi, yw;
    int vmin[] = new int[Math.max(w, h)];
    int divsum = (div + 1) >> 1;
    divsum *= divsum;
    int dv[] = new int[256 * divsum];
    for (i = 0; i < 256 * divsum; i++)
    {
      dv[i] = (i / divsum);
    }
    yw = yi = 0;
    int[][] stack = new int[div][3];
    int stackpointer;
    int stackstart;
    int[] sir;
    int rbs;
    int r1 = radius + 1;
    int routsum, goutsum, boutsum;
    int rinsum, ginsum, binsum;
    for (y = 0; y < h; y++)
    {
      rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
      for (i = -radius; i <= radius; i++)
      {
        p = pix[yi + Math.min(wm, Math.max(i, 0))];
        sir = stack[i + radius];
        sir[0] = (p & 0xff0000) >> 16;
        sir[1] = (p & 0x00ff00) >> 8;
        sir[2] = (p & 0x0000ff);
        rbs = r1 - Math.abs(i);
        rsum += sir[0] * rbs;
        gsum += sir[1] * rbs;
        bsum += sir[2] * rbs;
        if (i > 0)
        {
          rinsum += sir[0];
          ginsum += sir[1];
          binsum += sir[2];
        }
        else
        {
          routsum += sir[0];
          goutsum += sir[1];
          boutsum += sir[2];
        }
      }
      stackpointer = radius;
      for (x = 0; x < w; x++) 
      {
        r[yi] = dv[rsum];
        g[yi] = dv[gsum];
        b[yi] = dv[bsum];
        rsum -= routsum;
        gsum -= goutsum;
        bsum -= boutsum;
        stackstart = stackpointer - radius + div;
        sir = stack[stackstart % div];
        routsum -= sir[0];
        goutsum -= sir[1];
        boutsum -= sir[2];
        if (y == 0) 
        {
          vmin[x] = Math.min(x + radius + 1, wm);
        }
        p = pix[yw + vmin[x]];
        sir[0] = (p & 0xff0000) >> 16;
        sir[1] = (p & 0x00ff00) >> 8;
        sir[2] = (p & 0x0000ff);
        rinsum += sir[0];
        ginsum += sir[1];
        binsum += sir[2];
        rsum += rinsum;
        gsum += ginsum;
        bsum += binsum;
        stackpointer = (stackpointer + 1) % div;
        sir = stack[(stackpointer) % div];
        routsum += sir[0];
        goutsum += sir[1];
        boutsum += sir[2];
        rinsum -= sir[0];
        ginsum -= sir[1];
        binsum -= sir[2];
        yi++;
      }
      yw += w;
    }
    for (x = 0; x < w; x++) 
    {
      rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
      yp = -radius * w;
      for (i = -radius; i <= radius; i++) 
      {
        yi = Math.max(0, yp) + x;
        sir = stack[i + radius];
        sir[0] = r[yi];
        sir[1] = g[yi];
        sir[2] = b[yi];
        rbs = r1 - Math.abs(i);
        rsum += r[yi] * rbs;
        gsum += g[yi] * rbs;
        bsum += b[yi] * rbs;
        if (i > 0) 
        {
          rinsum += sir[0];
          ginsum += sir[1];
          binsum += sir[2];
        } 
        else 
        {
          routsum += sir[0];
          goutsum += sir[1];
          boutsum += sir[2];
        }
        if (i < hm) 
        {
          yp += w;
        }
      }
      yi = x;
      stackpointer = radius;
      for (y = 0; y < h; y++) 
      {
        pix[yi] = (0xff000000 & pix[yi]) | (dv[rsum] << 16) | (dv[gsum] << 8) | dv[bsum];
        rsum -= routsum;
        gsum -= goutsum;
        bsum -= boutsum;
        stackstart = stackpointer - radius + div;
        sir = stack[stackstart % div];
        routsum -= sir[0];
        goutsum -= sir[1];
        boutsum -= sir[2];
        if (x == 0) 
        {
          vmin[y] = Math.min(y + r1, hm) * w;
        }
        p = x + vmin[y];
        sir[0] = r[p];
        sir[1] = g[p];
        sir[2] = b[p];
        rinsum += sir[0];
        ginsum += sir[1];
        binsum += sir[2];
        rsum += rinsum;
        gsum += ginsum;
        bsum += binsum;
        stackpointer = (stackpointer + 1) % div;
        sir = stack[stackpointer];
        routsum += sir[0];
        goutsum += sir[1];
        boutsum += sir[2];
        rinsum -= sir[0];
        ginsum -= sir[1];
        binsum -= sir[2];
        yi += w;
      }
    }
    bitmap.setPixels(pix, 0, w, 0, 0, w, h);
    return (bitmap);
  }
}