如何将我的数据库[sqflite]中的图像显示到BoxDecoration中？在Flutter

Question

基本上，我有一个外部数据库，其中有存储为BLOB的图像。我设法检索了数据，但是我不知道一旦检索到它是什么字节？一个字符串？

此外，我从另一个类初始化了一个“ var frontImage”

我尝试将其转换为BoxDecoration的MemoryImage内的_bytesImage，但显示为

  

程序包：flutter / src / painting / image_provider.dart：断言失败   行x pos x字节！=空：不正确。

class Vocabulary {

  int _id;
  String _word;
  int _category;
  var _frontimage;  <-----

//Assume i have getters and setters

}


Uint8List _bytesImage;
int photoIndex = 0;


//My main screen class [not main.dart]

 @override
  void initState(){
    super.initState();
    final Future<Database> dbFuture = widget._databaseHelper.initDatabase();
    dbFuture.then((database){
      Future<List <Vocabulary>> listFuture = widget._databaseHelper.getVocabularyByCategory(1);
      listFuture.then((list){
        setState(() {
          widget.photos = list;
        });
      });
    });
  }


void _nextImage() { // next
    setState(() {
      photoIndex++;
      print("ID: " + widget.photos[photoIndex].id.toString() + "\n"
          "VOCABULARYWORD: " + widget.photos[photoIndex].word.toString() + "\n"
          "CATEGORY: " + widget.photos[photoIndex].category.toString() + "\n"
          "++++++++++++++++++++\n");
      print(widget.photos[photoIndex].frontimage.toString());
      var blob = widget.photos[photoIndex].frontimage;
      _bytesImage = Base64Decoder().convert(blob);
    }
    );}


//My Widget build

child: Container(
                          decoration: BoxDecoration(
                              borderRadius: BorderRadius.circular(25.0),
                              image: DecorationImage(
                              image: MemoryImage(_bytesImage), //images front
                                  fit: BoxFit.cover)),
                        ),

I wanted to convert whatever my var frontImage is, into a picture in my widget build.

我想将自己的var frontImage转换为小部件版本中的图片。