Fixed column and row header for DataTable on Flutter Dart. Basically it’s an horizontal scroll for the first row, a vertical scroll for the first column and a mixed horizontal and vertical scroll for the subtable. Then when you move the subtable, its controllers move the column and the row.
Here is a custom widget with an example of how to use it:
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final _rowsCells = [ [7, 8, 10, 8, 7], [10, 10, 9, 6, 6], [5, 4, 5, 7, 5], [9, 4, 1, 7, 8], [7, 8, 10, 8, 7], [10, 10, 9, 6, 6], [5, 4, 5, 7, 5], [9, 4, 1, 7, 8], [7, 8, 10, 8, 7], [10, 10, 9, 6, 6], [5, 4, 5, 7, 5], [9, 4, 1, 7, 8], [7, 8, 10, 8, 7], [10, 10, 9, 6, 6], [5, 4, 5, 7, 5], [9, 4, 1, 7, 8] ]; final _fixedColCells = [ "Pablo", "Gustavo", "John", "Jack", "Pablo", "Gustavo", "John", "Jack", "Pablo", "Gustavo", "John", "Jack", "Pablo", "Gustavo", "John", "Jack", ]; final _fixedRowCells = [ "Math", "Informatics", "Geography", "Physics", "Biology" ]; @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar(), body: CustomDataTable( rowsCells: _rowsCells, fixedColCells: _fixedColCells, fixedRowCells: _fixedRowCells, cellBuilder: (data) { return Text('$data', style: TextStyle(color: Colors.red)); }, ), ); } class CustomDataTable<T> extends StatefulWidget { final T fixedCornerCell; final List<T> fixedColCells; final List<T> fixedRowCells; final List<List<T>> rowsCells; final Widget Function(T data) cellBuilder; final double fixedColWidth; final double cellWidth; final double cellHeight; final double cellMargin; final double cellSpacing; CustomDataTable({ this.fixedCornerCell, this.fixedColCells, this.fixedRowCells, @required this.rowsCells, this.cellBuilder, this.fixedColWidth = 60.0, this.cellHeight = 56.0, this.cellWidth = 120.0, this.cellMargin = 10.0, this.cellSpacing = 10.0, }); @override State<StatefulWidget> createState() => CustomDataTableState(); } class CustomDataTableState<T> extends State<CustomDataTable<T>> { final _columnController = ScrollController(); final _rowController = ScrollController(); final _subTableYController = ScrollController(); final _subTableXController = ScrollController(); Widget _buildChild(double width, T data) => SizedBox( width: width, child: widget.cellBuilder?.call(data) ?? Text('$data')); Widget _buildFixedCol() => widget.fixedColCells == null ? SizedBox.shrink() : Material( color: Colors.lightBlueAccent, child: DataTable( horizontalMargin: widget.cellMargin, columnSpacing: widget.cellSpacing, headingRowHeight: widget.cellHeight, dataRowHeight: widget.cellHeight, columns: [ DataColumn( label: _buildChild( widget.fixedColWidth, widget.fixedColCells.first)) ], rows: widget.fixedColCells .sublist(widget.fixedRowCells == null ? 1 : 0) .map((c) => DataRow( cells: [DataCell(_buildChild(widget.fixedColWidth, c))])) .toList()), ); Widget _buildFixedRow() => widget.fixedRowCells == null ? SizedBox.shrink() : Material( color: Colors.greenAccent, child: DataTable( horizontalMargin: widget.cellMargin, columnSpacing: widget.cellSpacing, headingRowHeight: widget.cellHeight, dataRowHeight: widget.cellHeight, columns: widget.fixedRowCells .map((c) => DataColumn(label: _buildChild(widget.cellWidth, c))) .toList(), rows: []), ); Widget _buildSubTable() => Material( color: Colors.lightGreenAccent, child: DataTable( horizontalMargin: widget.cellMargin, columnSpacing: widget.cellSpacing, headingRowHeight: widget.cellHeight, dataRowHeight: widget.cellHeight, columns: widget.rowsCells.first .map((c) => DataColumn(label: _buildChild(widget.cellWidth, c))) .toList(), rows: widget.rowsCells .sublist(widget.fixedRowCells == null ? 1 : 0) .map((row) => DataRow( cells: row .map((c) => DataCell(_buildChild(widget.cellWidth, c))) .toList())) .toList())); Widget _buildCornerCell() => widget.fixedColCells == null || widget.fixedRowCells == null ? SizedBox.shrink() : Material( color: Colors.amberAccent, child: DataTable( horizontalMargin: widget.cellMargin, columnSpacing: widget.cellSpacing, headingRowHeight: widget.cellHeight, dataRowHeight: widget.cellHeight, columns: [ DataColumn( label: _buildChild( widget.fixedColWidth, widget.fixedCornerCell)) ], rows: []), ); @override void initState() { super.initState(); _subTableXController.addListener(() { _rowController.jumpTo(_subTableXController.position.pixels); }); _subTableYController.addListener(() { _columnController.jumpTo(_subTableYController.position.pixels); }); } @override Widget build(BuildContext context) { return Stack( children: <Widget>[ Row( children: <Widget>[ SingleChildScrollView( controller: _columnController, scrollDirection: Axis.vertical, physics: NeverScrollableScrollPhysics(), child: _buildFixedCol(), ), Flexible( child: SingleChildScrollView( controller: _subTableXController, scrollDirection: Axis.horizontal, child: SingleChildScrollView( controller: _subTableYController, scrollDirection: Axis.vertical, child: _buildSubTable(), ), ), ), ], ), Row( children: <Widget>[ _buildCornerCell(), Flexible( child: SingleChildScrollView( controller: _rowController, scrollDirection: Axis.horizontal, physics: NeverScrollableScrollPhysics(), child: _buildFixedRow(), ), ), ], ), ], ); } } |
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