Android 从字节格式检索图像格式：显示空值

这是我的数据库的图片，你们可以在这里看到图片以字节格式成功插入。 这种数据库结构

public void onCreate(SQLiteDatabase db) { 
    final String[] creatStatments = new String[]{"create table "
            + Image_handler
            + "(_id INTEGER PRIMARY KEY AUTOINCREMENT,"+ Image_handeler_column+" BLOB)" 
};

我使用以下代码从数据库中检索图像

          System.out.println(" satrt image rertrive");
        cursor = dh.rawQuery("SELECT _id, image_byte FROM image_database",null);
                int i=0;
        if (cursor.moveToFirst()) {
            do {
                   String str_cursor =cursor.getString(1);
                   System.out.println("string value of cursor"+str_cursor);

               // get  the  data into array,or class variable   
                bb = cursor.getBlob(cursor.getColumnIndex(DatabaseHelper.Image_handeler_column));
                System.out.println("byte array value"+bb);
            i++;  
            } while (cursor.moveToNext());
            Bitmap bmp=BitmapFactory.decodeByteArray(bb,0,bb.length);
            System.out.println("bitmap value"+bmp);

             imageView.setImageBitmap(bmp);

        }

当我在处理上面的代码时，字节数组的值显示出来B@405889a8对于我来说，bmp位图值为空。所以为什么我得到的bmp值为null。 我将更新我的问题。为了从url在数据库中插入图像，我使用以下代码

         static private Bitmap downloadBitmap(String url) throws IOException {
    HttpUriRequest request = new HttpGet(url);
    HttpClient httpClient = new DefaultHttpClient();
    HttpResponse response = httpClient.execute(request);

    StatusLine statusLine = response.getStatusLine();
    int statusCode = statusLine.getStatusCode();  
    if (statusCode == 200) {
        System.out.println("kjklcmklxc");
      HttpEntity entity = response.getEntity();
      byte[] bytes = EntityUtils.toByteArray(entity);

      Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0,
          bytes.length);
      bitmap.compress(Bitmap.CompressFormat.JPEG, 40, byt_aary_outpt_strm);
    dh.delete(DatabaseHelper.Image_handler, null, null);
      bitmapdata = byt_aary_outpt_strm.toByteArray();
      System.out.println("bitmap of image converted image");
      for(int i =0 ; i<bitmapdata.length;i++){
          convert_save_byte_str = convert_save_byte_str+bitmapdata[i];
      }
      System.out.println("njdsfnh"+convert_save_byte_str);
      ContentValues userdetailValues = new ContentValues();

        userdetailValues.put("image_byte", convert_save_byte_str);
        System.out.println("between put and insert");
        dh.insert(DatabaseHelper.Image_handler, null, userdetailValues); 
        cursor = dh.rawQuery("SELECT _id, image_byte FROM image_database",null);
        int i=0;
        if (cursor.moveToFirst()) {
            do {


               // get  the  data into array,or class variable   
                bb = cursor.getBlob(cursor.getColumnIndex(DatabaseHelper.Image_handeler_column));
                //System.out.println("productid"+data);
                //intent.putExtra("product_id", data);
                System.out.print("bytengkfgkjgk"+bb[i]);

            i++;
            } while (cursor.moveToNext());
        }

      return bitmap;    
    } else {
      throw new IOException("Download failed, HTTP response code "
          + statusCode + " - " + statusLine.getReasonPhrase());
    }
  }

---

当字节数组数据不是有效的位图格式时，decodeByteArray返回null。请显示您在数据库中插入的内容和方式。感谢您的回复。如果将字节转换为字符串不正确，我将更新我的问题。用正确的代码替换您的代码：。另外，我认为应该使用string.getBytes而不是getBlob@vorrtex谢谢你的回复，我试过你的建议，但对我不起作用。