照片压缩

 //压缩图片
    public Bitmap compressBitmap(int i) throws IOException {
        // 尺寸压缩倍数,值越大，图片尺寸越小
        int ratio = 2;
        // 压缩Bitmap到对应尺寸
        Bitmap bmp =BitmapFactory.decodeByteArray(items.get(i).getImageAsBytes(), 0, items.get(i).getImageAsBytes().length);
        Bitmap result = Bitmap.createBitmap(bmp.getWidth() / ratio, bmp.getHeight() / ratio, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(result);
        Rect rect = new Rect(0, 0, bmp.getWidth() / ratio, bmp.getHeight() / ratio);
        canvas.drawBitmap(bmp, null, rect, null);
        return result;
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        String path = Environment.getExternalStorageDirectory()+ "/Image/";
        File dirFile  = new File(path);  //目录转化成文件夹
        if (!dirFile .exists()) {       //如果不存在，建立这个文件夹
            dirFile .mkdirs();
        }
        //保存图片到文件夹
        File file = new File(path, items.get(i).getMessage()+ ".jpg");
        try {
            FileOutputStream  out = new FileOutputStream(file);
            // 把压缩后的数据存放到out中
            result.compress(Bitmap.CompressFormat.JPEG, 100 ,out);
            out.flush();
            out.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }