flutter DataTable数据表格

import 'package:flutter/material.dart';
import './model/post.dart';
class DataTableDemo extendsStatefulWidget {
  @override
  _DataTableDemoState createState() =>_DataTableDemoState();
}
class _DataTableDemoState extends State<DataTableDemo>{
  int_sortColumnIndex;
  bool _sortAscending = true;
  @override
  Widget build(BuildContext context) {
    returnScaffold(
      appBar: AppBar(
        title: Text('DataTableDemo'),
        elevation: 0.0,
      ),
      body: Container(
        padding: EdgeInsets.all(16.0),
        child: ListView(
          children: <Widget>[
            DataTable(
              sortColumnIndex: _sortColumnIndex,
              sortAscending: _sortAscending,
              //onSelectAll: (bool value) {},
columns: [
                DataColumn(
                  label: Text('Title'),
                  onSort: (intindex, bool ascending) {
                    setState(() {
                      _sortColumnIndex =index;
                      _sortAscending =ascending;
                      posts.sort((a, b) {
                        if (!ascending) {
                          final c =a;
                          a =b;
                          b =c;
                        }
                        returna.title.length.compareTo(b.title.length);
                      });
                    });
                  },
                ),
                DataColumn(
                  label: Text('Author'),
                ),
                DataColumn(
                  label: Text('Image'),
                ),
              ],
              rows: posts.map((post) {
                returnDataRow(
                  selected: post.selected,
                  onSelectChanged: (bool value) {
                    setState(() {
                      if (post.selected !=value) {
                        post.selected =value;
                      }
                    });
                  },
                  cells: [
                    DataCell(Text(post.title)),
                    DataCell(Text(post.author)),
                    DataCell(Image.network(post.imageUrl)),
                  ]
                );
              }).toList(),
            ),
          ],
        ),
      )
    );
  }
}

import 'package:flutter/material.dart';
import './model/post.dart';
class PostDataSource extendsDataTableSource {
  final List<Post> _posts =posts;
  int _selectedCount = 0;
  @override
  int get rowCount =>_posts.length;
  @override
  bool get isRowCountApproximate => false;
  @override
  int get selectedRowCount =>_selectedCount;
  @override
  DataRow getRow(intindex) {
    final Post post =_posts[index];
    returnDataRow.byIndex(
      index: index,
      cells: <DataCell>[
        DataCell(Text(post.title)),
        DataCell(Text(post.author)),
        DataCell(Image.network(post.imageUrl)),
      ],
    );
  }
  void_sort(getField(post), bool ascending) {
    _posts.sort((a, b) {
      if (!ascending) {
        final c =a;
        a =b;
        b =c;
      }
      final aValue =getField(a);
      final bValue =getField(b);
      returnComparable.compare(aValue, bValue);
    });
    notifyListeners();
  }
}
class PaginatedDataTableDemo extendsStatefulWidget {
  @override
  _PaginatedDataTableDemoState createState() =>_PaginatedDataTableDemoState();
}
class _PaginatedDataTableDemoState extends State<PaginatedDataTableDemo>{
  int_sortColumnIndex;
  bool _sortAscending = true;
  final PostDataSource _postsDataSource =PostDataSource();
  @override
  Widget build(BuildContext context) {
    returnScaffold(
        appBar: AppBar(
          title: Text('PaginatedDataTableDemo'),
          elevation: 0.0,
        ),
        body: Container(
          padding: EdgeInsets.all(16.0),
          child: ListView(
            children: <Widget>[
              PaginatedDataTable(
                header: Text('Posts'),
                rowsPerPage: 5,
                source: _postsDataSource,
                sortColumnIndex: _sortColumnIndex,
                sortAscending: _sortAscending,
                //onSelectAll: (bool value) {},
columns: [
                  DataColumn(
                    label: Text('Title'),
                    onSort: (intcolumnIndex, bool ascending) {
                      _postsDataSource._sort((post) =>post.title.length, ascending);
                      setState(() {
                        _sortColumnIndex =columnIndex;
                        _sortAscending =ascending;
                      });
                    },
                  ),
                  DataColumn(
                    label: Text('Author'),
                  ),
                  DataColumn(
                    label: Text('Image'),
                  ),
                ],
              ),
            ],
          ),
        ));
  }
}