activity背景毛玻璃效果

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:id="@+id/relative"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:background="@drawable/screenshot" >

 </RelativeLayout>

layout

 package com.example.hairglassbackdemo;

 import android.annotation.TargetApi;
 import android.app.Activity;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
 import android.graphics.Paint;
 import android.graphics.Rect;
 import android.graphics.drawable.BitmapDrawable;
 import android.os.Build;
 import android.os.Bundle;
 import android.support.v7.app.ActionBarActivity;
 import android.util.Log;
 import android.view.View;

 @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
 public class MainActivity extends ActionBarActivity {

     private Bitmap bitmap;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
     }

     @Override
     public void onWindowFocusChanged(boolean hasFocus) {
         super.onWindowFocusChanged(hasFocus);
         if (null == bitmap) {
             // 需要在actvity显示出来后 再进行截屏操作。这里进行模糊化图片是个耗时操作，建议在项目中放到非UI线程去做
             bitmap = takeScreenShot(MainActivity.this);
         }

         if (bitmap != null) {

              blur(bitmap, findViewById(R.id.relative));
         }
     }

     /**
      * 屏幕截图
      *
      * @param activity
      * @return
      */
     private Bitmap takeScreenShot(Activity activity) {
         // View是你需要截图的View
         View view = activity.getWindow().getDecorView();
         view.setDrawingCacheEnabled(true);
         view.buildDrawingCache();
         Bitmap b1 = view.getDrawingCache();

         // 获取状态栏高度
         Rect frame = new Rect();
         activity.getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
         int statusBarHeight = frame.top;

         // 获取屏幕长和高
         int width = activity.getWindowManager().getDefaultDisplay().getWidth();
         int height = activity.getWindowManager().getDefaultDisplay()
                 .getHeight();
         // 去掉标题栏
         // Bitmap b = Bitmap.createBitmap(b1, 0, 25, 320, 455);
         Bitmap b = Bitmap.createBitmap(b1, 0, statusBarHeight, width, height
                 - statusBarHeight);
         view.destroyDrawingCache();
         return b;
     }

     private void blur(Bitmap bkg, View view) {
         long startMs = System.currentTimeMillis();
         float radius = 2;
         float scaleFactor = 8;

         Bitmap overlay = Bitmap.createBitmap(
                 (int) (view.getMeasuredWidth() / scaleFactor),
                 (int) (view.getMeasuredHeight() / scaleFactor),
                 Bitmap.Config.ARGB_8888);
         Canvas canvas = new Canvas(overlay);
         canvas.translate(-view.getLeft() / scaleFactor, -view.getTop()
                 / scaleFactor);
         canvas.scale(1 / scaleFactor, 1 / scaleFactor);
         Paint paint = new Paint();
         paint.setFlags(Paint.FILTER_BITMAP_FLAG);
         canvas.drawBitmap(bkg, 0, 0, paint);
         overlay = FastBlur.doBlur(overlay, (int) radius, true);
         view.setBackground(new BitmapDrawable(getResources(), overlay));
         Log.e("Blur", "cost " + (System.currentTimeMillis() - startMs) + "ms");
     }
 }

activity

 package com.example.hairglassbackdemo;

 import android.graphics.Bitmap;

 public class FastBlur {
     public static Bitmap doBlur(Bitmap sentBitmap, int radius, boolean canReuseInBitmap) {

         // Stack Blur v1.0 from
         // http://www.quasimondo.com/StackBlurForCanvas/StackBlurDemo.html
         //
         // Java Author: Mario Klingemann <mario at="" quasimondo.com="">
         // http://incubator.quasimondo.com
         // created Feburary 29, 2004
         // Android port : Yahel Bouaziz <yahel at="" kayenko.com="">
         // http://www.kayenko.com
         // ported april 5th, 2012

         // This is a compromise between Gaussian Blur and Box blur
         // It creates much better looking blurs than Box Blur, but is
         // 7x faster than my Gaussian Blur implementation.
         //
         // I called it Stack Blur because this describes best how this
         // filter works internally: it creates a kind of moving stack
         // of colors whilst scanning through the image. Thereby it
         // just has to add one new block of color to the right side
         // of the stack and remove the leftmost color. The remaining
         // colors on the topmost layer of the stack are either added on
         // or reduced by one, depending on if they are on the right or
         // on the left side of the stack.
         //
         // If you are using this algorithm in your code please add
         // the following line:
         //
         // Stack Blur Algorithm by Mario Klingemann <mario@quasimondo.com>

         Bitmap bitmap;
         if (canReuseInBitmap) {
             bitmap = sentBitmap;
         } else {
             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];
         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++) {
                 // Preserve alpha channel: ( 0xff000000 & pix[yi] )
                 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);
     }
 }

FastBlur