import 'dart:math' as math;
import 'package:flutter/widgets.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/gestures.dart' show DragStartBehavior;
import 'button_bar.dart';
import 'card.dart';
import 'constants.dart';
import 'data_table.dart';
import 'data_table_source.dart';
import 'debug.dart';
import 'dropdown.dart';
import 'icon_button.dart';
import 'icons.dart';
import 'ink_decoration.dart';
import 'material_localizations.dart';
import 'progress_indicator.dart';
import 'theme.dart';
class PaginatedDataTable extends StatefulWidget {
PaginatedDataTable({
Key key,
this.header,
this.actions,
@required this.columns,
this.sortColumnIndex,
this.sortAscending = true,
this.onSelectAll,
this.dataRowHeight = kMinInteractiveDimension,
this.headingRowHeight = 56.0,
this.horizontalMargin = 24.0,
this.columnSpacing = 56.0,
this.initialFirstRowIndex = 0,
this.onPageChanged,
this.rowsPerPage = defaultRowsPerPage,
this.availableRowsPerPage = const <int>[defaultRowsPerPage, defaultRowsPerPage * 2, defaultRowsPerPage * 5, defaultRowsPerPage * 10],
this.onRowsPerPageChanged,
this.dragStartBehavior = DragStartBehavior.start,
@required this.source,
}) : assert(header == null),
assert(columns != null),
assert(dragStartBehavior != null),
assert(columns.isNotEmpty),
assert(sortColumnIndex == null || (sortColumnIndex >= 0 && sortColumnIndex < columns.length)),
assert(sortAscending != null),
assert(dataRowHeight != null),
assert(headingRowHeight != null),
assert(horizontalMargin != null),
assert(columnSpacing != null),
assert(rowsPerPage != null),
assert(rowsPerPage > 0),
assert(() {
if (onRowsPerPageChanged != null)
assert(availableRowsPerPage != null && availableRowsPerPage.contains(rowsPerPage));
return true;
}()),
assert(source != null),
super(key: key);
final Widget header;
final List<Widget> actions;
final List<DataColumn> columns;
final int sortColumnIndex;
final bool sortAscending;
final ValueSetter<bool> onSelectAll;
final double dataRowHeight;
final double headingRowHeight;
final double horizontalMargin;
final double columnSpacing;
final int initialFirstRowIndex;
final ValueChanged<int> onPageChanged;
final int rowsPerPage;
static const int defaultRowsPerPage = 10;
final List<int> availableRowsPerPage;
final ValueChanged<int> onRowsPerPageChanged;
final DataTableSource source;
final DragStartBehavior dragStartBehavior;
@override
PaginatedDataTableState createState() => PaginatedDataTableState();
}
class PaginatedDataTableState extends State<PaginatedDataTable> {
int _firstRowIndex;
int _rowCount;
bool _rowCountApproximate;
int _selectedRowCount;
final Map<int, DataRow> _rows = <int, DataRow>{};
@override
void initState() {
super.initState();
_firstRowIndex = PageStorage.of(context)?.readState(context) ?? widget.initialFirstRowIndex ?? 0;
widget.source.addListener(_handleDataSourceChanged);
_handleDataSourceChanged();
}
@override
void didUpdateWidget(PaginatedDataTable oldWidget) {
super.didUpdateWidget(oldWidget);
if (oldWidget.source != widget.source) {
oldWidget.source.removeListener(_handleDataSourceChanged);
widget.source.addListener(_handleDataSourceChanged);
_handleDataSourceChanged();
}
}
@override
void dispose() {
widget.source.removeListener(_handleDataSourceChanged);
super.dispose();
}
void _handleDataSourceChanged() {
setState(() {
_rowCount = widget.source.rowCount;
_rowCountApproximate = widget.source.isRowCountApproximate;
_selectedRowCount = widget.source.selectedRowCount;
_rows.clear();
});
}
/// Ensures that the given row is visible.
void pageTo(int rowIndex) {
final int oldFirstRowIndex = _firstRowIndex;
setState(() {
final int rowsPerPage = widget.rowsPerPage;
_firstRowIndex = (rowIndex ~/ rowsPerPage) * rowsPerPage;
});
if ((widget.onPageChanged != null) &&
(oldFirstRowIndex != _firstRowIndex))
widget.onPageChanged(_firstRowIndex);
}
DataRow _getBlankRowFor(int index) {
return DataRow.byIndex(
index: index,
cells: widget.columns.map<DataCell>((DataColumn column) => DataCell.empty).toList(),
);
}
DataRow _getProgressIndicatorRowFor(int index) {
bool haveProgressIndicator = false;
final List<DataCell> cells = widget.columns.map<DataCell>((DataColumn column) {
if (!column.numeric) {
haveProgressIndicator = true;
return const DataCell(CircularProgressIndicator());
}
return DataCell.empty;
}).toList();
if (!haveProgressIndicator) {
haveProgressIndicator = true;
cells[0] = const DataCell(CircularProgressIndicator());
}
return DataRow.byIndex(
index: index,
cells: cells,
);
}
List<DataRow> _getRows(int firstRowIndex, int rowsPerPage) {
final List<DataRow> result = <DataRow>[];
final int nextPageFirstRowIndex = firstRowIndex + rowsPerPage;
bool haveProgressIndicator = false;
for (int index = firstRowIndex; index < nextPageFirstRowIndex; index += 1) {
DataRow row;
if (index < _rowCount || _rowCountApproximate) {
row = _rows.putIfAbsent(index, () => widget.source.getRow(index));
if (row == null && !haveProgressIndicator) {
row ??= _getProgressIndicatorRowFor(index);
haveProgressIndicator = true;
}
}
row ??= _getBlankRowFor(index);
result.add(row);
}
return result;
}
void _handlePrevious() {
pageTo(math.max(_firstRowIndex - widget.rowsPerPage, 0));
}
void _handleNext() {
pageTo(_firstRowIndex + widget.rowsPerPage);
}
final GlobalKey _tableKey = GlobalKey();
@override
Widget build(BuildContext context) {
assert(debugCheckHasMaterialLocalizations(context));
final ThemeData themeData = Theme.of(context);
final MaterialLocalizations localizations = MaterialLocalizations.of(context);
// HEADER
final List<Widget> headerWidgets = <Widget>[];
double startPadding = 24.0;
if (_selectedRowCount == 0) {
// headerWidgets.add(Expanded(child: widget.header));
if (widget.header is ButtonBar) {
startPadding = 12.0;
}
} else {
headerWidgets.add(Expanded(
child: Text(localizations.selectedRowCountTitle(_selectedRowCount)),
));
}
if (widget.actions != null) {
headerWidgets.addAll(
widget.actions.map<Widget>((Widget action) {
return Padding(
// 8.0 is the default padding of an icon button
padding: const EdgeInsetsDirectional.only(start: 24.0 - 8.0 * 2.0),
child: action,
);
}).toList()
);
}
// FOOTER
final TextStyle footerTextStyle = themeData.textTheme.caption;
final List<Widget> footerWidgets = <Widget>[];
if (widget.onRowsPerPageChanged != null) {
final List<Widget> availableRowsPerPage = widget.availableRowsPerPage
.where((int value) => value <= _rowCount || value == widget.rowsPerPage)
.map<DropdownMenuItem<int>>((int value) {
return DropdownMenuItem<int>(
value: value,
child: Text('$value'),
);
})
.toList();
footerWidgets.addAll(<Widget>[
Container(width: 14.0), // to match trailing padding in case we overflow and end up scrolling
Text(localizations.rowsPerPageTitle),
ConstrainedBox(
constraints: const BoxConstraints(minWidth: 64.0), // 40.0 for the text, 24.0 for the icon
child: Align(
alignment: AlignmentDirectional.centerEnd,
child: DropdownButtonHideUnderline(
child: DropdownButton<int>(
items: availableRowsPerPage,
value: widget.rowsPerPage,
onChanged: widget.onRowsPerPageChanged,
style: footerTextStyle,
iconSize: 24.0,
),
),
),
),
]);
}
footerWidgets.addAll(<Widget>[
Container(width: 32.0),
Text(
localizations.pageRowsInfoTitle(
_firstRowIndex + 1,
_firstRowIndex + widget.rowsPerPage,
_rowCount,
_rowCountApproximate,
),
),
Container(width: 32.0),
IconButton(
icon: const Icon(Icons.chevron_left),
padding: EdgeInsets.zero,
tooltip: localizations.previousPageTooltip,
onPressed: _firstRowIndex <= 0 ? null : _handlePrevious,
),
Container(width: 24.0),
IconButton(
icon: const Icon(Icons.chevron_right),
padding: EdgeInsets.zero,
tooltip: localizations.nextPageTooltip,
onPressed: (!_rowCountApproximate && (_firstRowIndex + widget.rowsPerPage >= _rowCount)) ? null : _handleNext,
),
Container(width: 14.0),
]);
// CARD
return Card(
semanticContainer: false,
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
Semantics(
container: true,
child: DefaultTextStyle(
style: _selectedRowCount > 0 ? themeData.textTheme.subhead.copyWith(color: themeData.accentColor)
: themeData.textTheme.title.copyWith(fontWeight: FontWeight.w400),
child: IconTheme.merge(
data: const IconThemeData(
opacity: 0.54
),
child: Ink(
height: 0.0,
color: _selectedRowCount > 0 ? themeData.secondaryHeaderColor : null,
child: Padding(
padding: EdgeInsetsDirectional.only(start: startPadding, end: 0.0),
child: Row(
mainAxisAlignment: MainAxisAlignment.end,
children: headerWidgets,
),
),
),
),
),
),
SingleChildScrollView(
scrollDirection: Axis.horizontal,
dragStartBehavior: widget.dragStartBehavior,
child: DataTable(
key: _tableKey,
columns: widget.columns,
sortColumnIndex: widget.sortColumnIndex,
sortAscending: widget.sortAscending,
onSelectAll: widget.onSelectAll,
dataRowHeight: widget.dataRowHeight,
headingRowHeight: widget.headingRowHeight,
horizontalMargin: widget.horizontalMargin,
columnSpacing: widget.columnSpacing,
rows: _getRows(_firstRowIndex, widget.rowsPerPage),
),
),
DefaultTextStyle(
style: footerTextStyle,
child: IconTheme.merge(
data: const IconThemeData(
opacity: 0.54
),
child: Container(
height: 56.0,
child: SingleChildScrollView(
dragStartBehavior: widget.dragStartBehavior,
scrollDirection: Axis.horizontal,
reverse: true,
child: Row(
children: footerWidgets,
),
),
),
),
),
],
),
);
}
}
它的工作原理，将其替换在Paginated_data_table.dart中。 Flutter标头变为Null，现在您可以在模拟器中提供空白，对我来说它的工作。然后，如果我们可以将标题保留在您的flutter应用程序中，则可以编辑代码。您可以参考https://flutter.dev/，在flutter中还有另一个Refer链接，以查看关于flutter paginatedatatable https://pub.dev/documentation/flutter_for_web/latest/material/PaginatedDataTable-class.html
的信息。