When I access the first character from the list of names the list view gives me error in flutter-CodePudding

I have below code in flutter which shows the list of the names with rank. All are working fine but I want to access the first character of the lastName. When I do this, throws the error Bad State: No element.

class ThisMonthTab extends StatelessWidget {
  const ThisMonthTab({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 10),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          Expanded(
            child: StreamBuilder<List<UserModel>>(
                stream: PlayersRepo.fetchThisMonthPlayersList(),
                builder: (context, snapshot) {
                  List<UserModel>? list = snapshot.data;
                  if (snapshot.connectionState == ConnectionState.waiting) {
                    return getLoader();
                  }
                  if (snapshot.data!.isEmpty) {
                    return emptyPageMessage(
                        LocaleKeys.noProgressThisMonth.tr());
                  }
                 
                  if (snapshot.hasData) {
                    log(snapshot.data!.length.toString());
                    return ListView.builder(
                      shrinkWrap: true,
                      itemCount: list?.length,
                      padding: const EdgeInsets.only(top: 10),
                      itemBuilder: (context, index) => LeaderboardTileWidget(
                        imageUrl: list![index].avatarUrl,
                        title:
                            '${list[index].firstName} ${list[index].lastName.characters.first}.', //Error is here in this line for accessing the first character of last name
                        subtitle:
                            '${LocaleKeys.level.tr()} ${list[index].currentLevel} (${list[index].currentRankName.characters.first}), ${list[index].monthlyXP.gainedXP} XP',
                        isUser: list[index].id ==
                            context.read<UserModelProvider>().user.email,
                        rankNo: index   1,
                      ),
                    );
                  } else {
                    return emptyPageMessage(LocaleKeys.fetchError.tr());
                  }
                }),
          ),
          const SizedBox(height: 10),
          Text(
            LocaleKeys.leaderboardDescription.tr(),
            style: Theme.of(context).textTheme.subtitle1?.copyWith(
                fontSize: 9, color: Colors.grey.shade600, letterSpacing: 0.4),
          ),
          const SizedBox(height: 70)
        ],
      ),
    );
  }
}

Can anyone figure out what is the mistake here because directly if I am displaying the list[index].lastName it works totally fine.

CodePudding user response：

If you just want the first character of the last name, why not go the JS way, just change

list[index].lastName.characters.first

list[index].lastName[0]

For safe bet, you may want to convert it to String first as

list[index].lastName.toString()[0]

The reasoning is, at the EOD, a String is just an Array of Characters and by [0], we're picking its first item. You can run and check this at the Dart Playground.

CodePudding user response：

I have just solved the error by checking if lastName is Empty or Not. In the list of the names it was broken where the names does not have last name.

I have changed list[index].lastName.characters.first to list[index].lastName.isEmpty ? " " : list[index].lastName.characters.first

Hope this helps someone.