獲取錯誤型別int不是字串的子型別

我為 sqlite 創建了一個演示，其中我創建了一個模型類類別模型，并且在 sqlite 中我在其 on create 方法中創建了一些默認類別，現在想使用未來的構建器在主螢屏上顯示所有類別，但它的執行錯誤部分是功能構建器..和應用程式以中心文本開頭

type int is not a subtype of string

類別模型

class CategoryModel{
  String title;
  IconData icon;
  int entries;
  double totalamount;

  CategoryModel({required this.title,this.entries=0,required this.icon,this.totalamount=0.0});

  Map<String,dynamic> tomap()
  {
    return {
      'title':title,
      'entries':entries,
      'totalamount':totalamount.toString()
    };
  }


  factory CategoryModel.frommap(Map<String,dynamic> map)
  {
    return CategoryModel(
        title: map['title'],
        icon: icons[map['title']]!,
        entries: map['entries'],
        totalamount: double.parse(map['totalamount'])
    );
  }

}

這是我使用 futurebuilder 的小部件

Widget getbody()
  {
    return FutureBuilder(
      future: SqfliteProvider.fetchcategory(),
      builder: (context,AsyncSnapshot<List<CategoryModel>?>snapshot){
        if (snapshot.connectionState == ConnectionState.waiting) {
          return CircularProgressIndicator();
        } else if (snapshot.hasError) {
          return Center(
            child: Text(snapshot.error.toString() ' Founded'),
          );
        } else if (snapshot.hasData) {
          if (snapshot.data != null) {
            return ListView.builder(
                itemCount: snapshot.data!.length,
                itemBuilder: (context, index) {
                  CategoryModel t = snapshot.data![index];

                  print(t.title.toString());
                  print(' ');
                  print(t.entries.toString());
                  print(' ');
                  print(t.totalamount.toString());

                  return Card(
                    child: ListTile(
                      leading: CircleAvatar(
                        child:   Icon(icons[t.title]),

                      ),
                      title: Text(t.title.toString(),style: TextStyle(fontSize: 18,fontWeight: FontWeight.bold),),
                      subtitle:Text(
                        "Entries :" t.entries.toString(),
                        style: TextStyle(fontSize: 14),
                      ) ,

                    ),
                  );
                });
          } else {
            return Text('Something wrong');
          }
        } else {
          return Text('Last if');
        }

      },
    );

  }

這是我的資料庫助手類

class SqfliteProvider {
  static Future<Database> _getdb() async {
    return openDatabase(join(await getDatabasesPath(), 'expensedb1.db'),
        version: 1,
        onCreate: (db,version) {
        db.execute("CREATE TABLE categorytb(title TEXT NOT NULL,entries INTEGER NOT NULL,totalamount STRING NOT NULL)");


      //add some default categories
      print('I am ready to call');
          for(int x=0;x<icons.length;x  )
           {
             db.insert('categorytb', {
               'title':icons.keys.toList()[x],
               'entries':0,
               'totalamount':(0.0).toString()
             });
           }

        });
  }

  static Future<List<CategoryModel>?> fetchcategory() async{
    final db=await _getdb();

    List<CategoryModel> templist=[];
    List<Map<String,dynamic>> maplist=await db.query('categorytb');

    print(maplist.toString());


    if(maplist.isEmpty)
      return null;

    templist=maplist.map((e) => CategoryModel.frommap(e)).toList();
    return templist;

  }




}

uj5u.com熱心網友回復：

嘗試轉換為字串。

factory CategoryModel.frommap(Map<String, dynamic> map) {
  IconData getIconData(data) {
    try {
      return IconData(data);
    } catch (e) {
      return IconData(Icons.abc.codePoint);
    }
  }

  return CategoryModel(
    title: map['title'].toString(),
    icon: getIconData(map['title']), // pass different data if needed
    entries: int.tryParse(map['entries'].toString()) ?? 0,
    totalamount: double.tryParse(map['totalamount']) ?? 0,
  );
}

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