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  • android 接收服务端 oracle数据中存储的blob对象 转化为图像

    服务端比较好处理:

    直接返回一个String类型

    return Base64.encode(rs.getBytes("BLOB字段名"));

    其中,rs为resultSet,接收查询语句的结果

    客户端:

    byte[] b = Base64.decode(ru,Base64.DEFAULT);
    Bitmap bitmap = BitMapUtil.getBitmapFromByte(b);
    if(bitmap!=null)
     {
        setBigBitmap(bitmap);
      }

     其中,ru为服务端返回的字符串

    BitMapUtil.java:

    public class BitMapUtil {
        /**
         * 根据本地图片的path获得Bitmap
         * @param url
         * @return
         */
        public static Bitmap getBitmapFromByte(byte[] b) {
            try {
                 BitmapFactory.Options opts = new BitmapFactory.Options();
                 /**
                  * ALPHA_8:每个像素占用 1byte 内存、
                  * ARGB_4444:每个像素占用 2byte 内存、
                  * ARGB_8888:每个像素占用 4byte 内存、
                  * RGB_565:每个像素占用 2byte 内存。
                  * Android默认的颜色模式为ARGB_8888
                  */
                 opts.inPreferredConfig = Bitmap.Config.RGB_565;//
                 opts.inPurgeable = true;  
                 opts.inInputShareable = true; 
                 opts.inJustDecodeBounds = true;
                 BitmapFactory.decodeByteArray(b, 0, b.length, opts);
                 opts.inSampleSize = computeSampleSize(opts, -1, 1024*1024);
                 opts.inJustDecodeBounds = false;
                 Bitmap bmp = BitmapFactory.decodeByteArray(b, 0, b.length, opts);
                 return bmp;
            } catch (Exception e) {
                 e.printStackTrace();
                 return null;
            }
        }
        /**
         * 计算 bitmap 尺寸
         * @param options
         * @param minSideLength
         * @param maxNumOfPixels
         * @return
         */
        private static int computeSampleSize(BitmapFactory.Options options,
                int minSideLength, int maxNumOfPixels) {
            int initialSize = computeInitialSampleSize(options, minSideLength,
                    maxNumOfPixels);
            int roundedSize;
            if (initialSize <= 8) {
                roundedSize = 1;
                while (roundedSize < initialSize) {
                    roundedSize <<= 1;
                }
            } else {
                roundedSize = (initialSize + 7) / 8 * 8;
            }
            return roundedSize;
        }
    
        /**
         * 计算 bitmap 尺寸
         * @param options
         * @param minSideLength
         * @param maxNumOfPixels
         * @return
         */
        private static int computeInitialSampleSize(BitmapFactory.Options options,
                int minSideLength, int maxNumOfPixels) {
            double w = options.outWidth;
            double h = options.outHeight;
            int lowerBound = (maxNumOfPixels == -1) ? 1 : (int) Math.ceil(Math
                    .sqrt(w * h / maxNumOfPixels));
            int upperBound = (minSideLength == -1) ? 128 : (int) Math.min(Math
                    .floor(w / minSideLength), Math.floor(h / minSideLength));
            if (upperBound < lowerBound) {
                return lowerBound;
            }
            if ((maxNumOfPixels == -1) && (minSideLength == -1)) {
                return 1;
            } else if (minSideLength == -1) {
                return lowerBound;
            } else {
                return upperBound;
            }
        }
    }

    setBigBitmap(Bitmap bitmap)

        public void setBigBitmap(Bitmap bigBitmap) {
            this.bigBitmap = bigBitmap;
            if(cWidth!=0&&cHeight!=0)
            {
                this.setImageBitmap(Bitmap.createScaledBitmap(bigBitmap, cWidth,cHeight, false));
                
            }
            else
            {
                this.setImageBitmap(Bitmap.createScaledBitmap(bigBitmap, this.getWidth(), this.getHeight(), false));
            }
        }

    setBigBitmap(Bitmap bitmap)方法是位于一个继承ImageView的类中

    这样,这个功能就完成了,需要的时候写个LinearLayout ,add上去就可以了

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  • 原文地址:https://www.cnblogs.com/goldeneast/p/3406509.html
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