Android 简单图片浏览器 读取sdcard图片+形成缩略图+Gallery

    //想要的返回值所在的列
            String[] projection = { MediaStore.Images.Thumbnails._ID};
            //图片信息存储在 android.provider.MediaStore.Images.Thumbnails数据库 
            //快速查询数据库中的图片对应存放路劲         
            Cursor cursor = managedQuery(
                    MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI,
                    projection, //List of columns to return ：想要他返回的列
                    null, // Return all rows
                    null,
                    null);
            int columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Thumbnails._ID);
            uriArray = new Uri[cursor.getCount()];//把图片路径放在数组中

    while(cursor.moveToNext()&&i<cursor.getCount())
            {   //移到指定的位置，遍历数据库
                cursor.moveToPosition(i);
                uri = Uri.withAppendedPath(MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI,cursor.getInt(columnIndex)+"");
                uriArray[i]=uri;
                try {
                    bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(uri));
                    if (bitmap != null) {
                        //将原来的位图转换成新的位图
                        newBitmap = Bitmap.createScaledBitmap(bitmap,80, 80,true);
                        bitmap.recycle();//释放内存
                        if (newBitmap != null) {
                            publishProgress(new LoadedImage(newBitmap));
                        }
                    }
                } catch (IOException e) {}
                i++;
            }