flutter - 如何在flutter中设计实现多列 ListView ？

Question

我正在开发一个新的应用程序，它将以表格格式列出数据库内容。就像我想在回收站 View 中显示它一样，它有 4 列和单独的列标题。我不知道如何在支持多列的 flutter 中使用 ListView 。

我尝试了以下替代方案

  Widget listViewWidget(List<DashboardResponse> dashboard) {
    var listView = ListView.builder(
            itemCount: dashboard.length,
            itemBuilder: (context, position) {
                    return new Row(
                        mainAxisAlignment: MainAxisAlignment.center,
                        mainAxisSize: MainAxisSize.max,
                        crossAxisAlignment: CrossAxisAlignment.center,
                        children: <Widget>[
                            Flexible(
                                child: Text ('${dashboard[position].spvName}'),
                            ),
                            Flexible(
                                child: Text ('${dashboard[position].mobileCount}'),
                            ),
                            Flexible(
                                child: Text ('${dashboard[position].webCount}'),
                            ),
                        ],
                    );
            }
    );

    return listView;
}

另一种方式

        var listView = ListView.builder(
            itemCount: dashboard.length,
                    itemBuilder: (context, position) {
                        return ListTile(
                                title: Text(
                                    '${dashboard[position].spvName}',
                                    style: TextStyle(
                                            fontSize: 18.0,
                                            color: Colors.amber,
                                            fontWeight: FontWeight.bold),
                                ),
                        );
                    }
        );

        return listView;
    }




[![Multicolumn listview][1]][1]


  [1]: /image/EoVxy.jpg

Answer 1

ListView 添加Column header 需要额外注意，请引用this。 Flutter : Can I add a Header Row to a ListView代码片段

通过 itemBuilder 将标题作为第一行返回:

ListView.builder(
    itemCount: data == null ? 1 : data.length + 1,
    itemBuilder: (BuildContext context, int index) {
        if (index == 0) {
            // return the header
            return new Column(...);
        }
        index -= 1;

        // return row
        var row = data[index];
        return new InkWell(... with row ...);
    },
);

DataTable支持列标题你可以考虑用DataTable实现，请查看下面的例子。

完整代码

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: DataTableDemo(),
    );
  }
}



class User {
  String firstName;
  String lastName;

  User({this.firstName, this.lastName});

  static List<User> getUsers() {
    return <User>[
      User(firstName: "Aaryan", lastName: "Shah"),
      User(firstName: "Ben", lastName: "John"),
      User(firstName: "Carrie", lastName: "Brown"),
      User(firstName: "Deep", lastName: "Sen"),
      User(firstName: "Emily", lastName: "Jane"),
    ];
  }
}

class DataTableDemo extends StatefulWidget {
  DataTableDemo() : super();

  final String title = "Data Table Flutter Demo";

  @override
  DataTableDemoState createState() => DataTableDemoState();
}

class DataTableDemoState extends State<DataTableDemo> {
  List<User> users;
  List<User> selectedUsers;
  bool sort;

  @override
  void initState() {
    sort = false;
    selectedUsers = [];
    users = User.getUsers();
    super.initState();
  }

  onSortColum(int columnIndex, bool ascending) {
    if (columnIndex == 0) {
      if (ascending) {
        users.sort((a, b) => a.firstName.compareTo(b.firstName));
      } else {
        users.sort((a, b) => b.firstName.compareTo(a.firstName));
      }
    }
  }

  onSelectedRow(bool selected, User user) async {
    setState(() {
      if (selected) {
        selectedUsers.add(user);
      } else {
        selectedUsers.remove(user);
      }
    });
  }

  deleteSelected() async {
    setState(() {
      if (selectedUsers.isNotEmpty) {
        List<User> temp = [];
        temp.addAll(selectedUsers);
        for (User user in temp) {
          users.remove(user);
          selectedUsers.remove(user);
        }
      }
    });
  }

  SingleChildScrollView dataBody() {
    return SingleChildScrollView(
      scrollDirection: Axis.vertical,
      child: DataTable(
        sortAscending: sort,
        sortColumnIndex: 0,
        columns: [
          DataColumn(
              label: Text("FIRST NAME"),
              numeric: false,
              tooltip: "This is First Name",
              onSort: (columnIndex, ascending) {
                setState(() {
                  sort = !sort;
                });
                onSortColum(columnIndex, ascending);
              }),
          DataColumn(
            label: Text("LAST NAME"),
            numeric: false,
            tooltip: "This is Last Name",
          ),
        ],
        rows: users
            .map(
              (user) => DataRow(
              selected: selectedUsers.contains(user),
              onSelectChanged: (b) {
                print("Onselect");
                onSelectedRow(b, user);
              },
              cells: [
                DataCell(
                  Text(user.firstName),
                  onTap: () {
                    print('Selected ${user.firstName}');
                  },
                ),
                DataCell(
                  Text(user.lastName),
                ),
              ]),
        )
            .toList(),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Column(
        mainAxisSize: MainAxisSize.min,
        mainAxisAlignment: MainAxisAlignment.center,
        verticalDirection: VerticalDirection.down,
        children: <Widget>[
          Expanded(
            child: dataBody(),
          ),
          Row(
            mainAxisAlignment: MainAxisAlignment.center,
            mainAxisSize: MainAxisSize.min,
            children: <Widget>[
              Padding(
                padding: EdgeInsets.all(20.0),
                child: OutlineButton(
                  child: Text('SELECTED ${selectedUsers.length}'),
                  onPressed: () {},
                ),
              ),
              Padding(
                padding: EdgeInsets.all(20.0),
                child: OutlineButton(
                  child: Text('DELETE SELECTED'),
                  onPressed: selectedUsers.isEmpty
                      ? null
                      : () {
                    deleteSelected();
                  },
                ),
              ),
            ],
          ),
        ],
      ),
    );
  }
}