如何使列表视图与 itemBuilder 一起使用

Question

i can't seem to solve this problem, for me the code it's correct, but i can't see where the error is. What do i need to return for the listview? Should i put the listview.builder in another place? the listbuild is returning the _buildTitleSection and the _buildCreditCard so i can't seem to understand it.

  @override
  Widget build(BuildContext context) {
    return SingleChildScrollView(
      child: Container(
        padding: const EdgeInsets.all(8.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            ListView.builder(
               itemCount: users == null ? 0 : users.length,
              itemBuilder: (context, index) { //This is giving me "error" *** 
                _buildTitleSection(
                    title: "Names", subTitle: "User informations");
                _buildCreditCard(
                    url: users[index].imageURL,
                    color: Color(0xFF1E90FF),
                    cardExpiration: users[index].cardExpiration,
                    cardHolder: users[index].cardHolder,
                    cardNumber: users[index].cardNumber);
                SizedBox(
                  height: 15,
                );
              },
            ),
          ],
        ),
      ),
    );
  }

***This function has a return type of 'Widget', but doesn't end with a return statement. Try adding a return statement, or changing the return type to 'void'.

Answer 1

Builder methods need to return an object of type Widget so in order to get your code working you need to return your widgets, you have more than one widget, you have to wrap them in a Column or a Row..

  @override
  Widget build(BuildContext context) {
    return SingleChildScrollView(
      child: Container(
        padding: const EdgeInsets.all(8.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            ListView.builder(
               itemCount: users == null ? 0 : users.length,
              itemBuilder: (context, index) {
                return Column(
                   children: [
                        _buildTitleSection(
                            title: "Names", subTitle: "User informations"),
                        _buildCreditCard(
                            url: users[index].imageURL,
                            color: Color(0xFF1E90FF),
                            cardExpiration: users[index].cardExpiration,
                            cardHolder: users[index].cardHolder,
                            cardNumber: users[index].cardNumber),
                        SizedBox(
                            height: 15,
                        ),
                    ]
                );
              },
            ),
          ],
        ),
      ),
    );
  }