Android 图片 添加高斯模糊

 private static Bitmap activityShot(Activity activity) {

        /*获取windows中最顶层的view*/
        View view = activity.getWindow().getDecorView();
        //允许当前窗口保存缓存信息
        view.setDrawingCacheEnabled(true);
        view.buildDrawingCache(true);

//        //获取状态栏高度
//        Rect rect = new Rect();
//        view.getWindowVisibleDisplayFrame(rect);
//        int statusBarHeight = rect.top;
//
//        WindowManager windowManager = activity.getWindowManager();
//
//        //获取屏幕宽和高
//        DisplayMetrics outMetrics = new DisplayMetrics();
//        windowManager.getDefaultDisplay().getMetrics(outMetrics);
//        int width = outMetrics.widthPixels;
//        int height = outMetrics.heightPixels;
//
//        //去掉状态栏
//        Bitmap shotBitmap = Bitmap.createBitmap(view.getDrawingCache(), 0, statusBarHeight, width,
//                height - statusBarHeight);

        //压缩系数2，4，8
        float scaleFactor = 8;
        Bitmap scaledBitmap = Bitmap.createBitmap(
                (int) (view.getMeasuredWidth() / scaleFactor),
                (int) (view.getMeasuredHeight() / scaleFactor),
                Bitmap.Config.ARGB_8888);

        Canvas canvas = new Canvas(scaledBitmap);
        canvas.translate(-view.getLeft() / scaleFactor, -view.getTop() / scaleFactor);
        canvas.scale(1 / scaleFactor, 1 / scaleFactor);
        Paint paint = new Paint();
        paint.setFlags(Paint.FILTER_BITMAP_FLAG);
        // 截屏view.getDrawingCache()
        canvas.drawBitmap(view.getDrawingCache(), 0, 0, paint);
        //销毁缓存信息
        view.destroyDrawingCache();
        view.setDrawingCacheEnabled(false);
        return scaledBitmap;
    }

将return的scaleBitmap放入下面的方法：

private static Bitmap rsBlur(Context context, Bitmap source, int radius) {
        Bitmap inputBmp = source;
        //(1)
        //初始化一个RenderScript Context
        RenderScript renderScript = RenderScript.create(context);
        // Allocate memory for Renderscript to work with
        //(2)
        //创建输入输出的allocation
        final Allocation input = Allocation.createFromBitmap(renderScript, inputBmp);
        final Allocation output = Allocation.createTyped(renderScript, input.getType());
        //(3)
        // Load up an instance of the specific script that we want to use.
        //创建ScriptIntrinsic
        ScriptIntrinsicBlur scriptIntrinsicBlur = ScriptIntrinsicBlur.create(renderScript, Element.U8_4(renderScript));
        //(4)
        //填充数据
        scriptIntrinsicBlur.setInput(input);
        //(5)
        // Set the blur radius
        //设置模糊半径
        scriptIntrinsicBlur.setRadius(radius);
        //(6)
        // Start the ScriptIntrinisicBlur
        //启动内核
        scriptIntrinsicBlur.forEach(output);
        //(7)
        // Copy the output to the blurred bitmap
        //copy数据
        output.copyTo(inputBmp);
        //(8)
        //销毁renderScript
        renderScript.destroy();
        return inputBmp;
    }

不用的时候要remove掉：

    public void removeMask(){
        if (group != null){
            for(int i=0;i<group.getChildCount();i++){
                group.removeView(imageView);
            }
        }
    }