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// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:collection';
import 'package:flutter/foundation.dart';
import 'package:flutter/rendering.dart';
import 'basic.dart';
import 'debug.dart';
import 'framework.dart';
import 'image.dart';
export 'package:flutter/rendering.dart' show
FixedColumnWidth,
FlexColumnWidth,
FractionColumnWidth,
IntrinsicColumnWidth,
MaxColumnWidth,
MinColumnWidth,
TableBorder,
TableCellVerticalAlignment,
TableColumnWidth;
/// A horizontal group of cells in a [Table].
///
/// Every row in a table must have the same number of children.
///
/// The alignment of individual cells in a row can be controlled using a
/// [TableCell].
@immutable
class TableRow {
/// Creates a row in a [Table].
const TableRow({ this.key, this.decoration, this.children });
/// An identifier for the row.
final LocalKey? key;
/// A decoration to paint behind this row.
///
/// Row decorations fill the horizontal and vertical extent of each row in
/// the table, unlike decorations for individual cells, which might not fill
/// either.
final Decoration? decoration;
/// The widgets that comprise the cells in this row.
///
/// Children may be wrapped in [TableCell] widgets to provide per-cell
/// configuration to the [Table], but children are not required to be wrapped
/// in [TableCell] widgets.
final List<Widget>? children;
@override
String toString() {
final StringBuffer result = StringBuffer();
result.write('TableRow(');
if (key != null) {
result.write('$key, ');
}
if (decoration != null) {
result.write('$decoration, ');
}
if (children == null) {
result.write('child list is null');
} else if (children!.isEmpty) {
result.write('no children');
} else {
result.write('$children');
}
result.write(')');
return result.toString();
}
}
class _TableElementRow {
const _TableElementRow({ this.key, required this.children });
final LocalKey? key;
final List<Element> children;
}
/// A widget that uses the table layout algorithm for its children.
///
/// {@youtube 560 315 https://www.youtube.com/watch?v=_lbE0wsVZSw}
///
/// {@tool dartpad}
/// This sample shows a [Table] with borders, multiple types of column widths
/// and different vertical cell alignments.
///
/// ** See code in examples/api/lib/widgets/table/table.0.dart **
/// {@end-tool}
///
/// If you only have one row, the [Row] widget is more appropriate. If you only
/// have one column, the [SliverList] or [Column] widgets will be more
/// appropriate.
///
/// Rows size vertically based on their contents. To control the individual
/// column widths, use the [columnWidths] property to specify a
/// [TableColumnWidth] for each column. If [columnWidths] is null, or there is a
/// null entry for a given column in [columnWidths], the table uses the
/// [defaultColumnWidth] instead.
///
/// By default, [defaultColumnWidth] is a [FlexColumnWidth]. This
/// [TableColumnWidth] divides up the remaining space in the horizontal axis to
/// determine the column width. If wrapping a [Table] in a horizontal
/// [ScrollView], choose a different [TableColumnWidth], such as
/// [FixedColumnWidth].
///
/// For more details about the table layout algorithm, see [RenderTable].
/// To control the alignment of children, see [TableCell].
///
/// See also:
///
/// * The [catalog of layout widgets](https://flutter.dev/widgets/layout/).
class Table extends RenderObjectWidget {
/// Creates a table.
///
/// The [children], [defaultColumnWidth], and [defaultVerticalAlignment]
/// arguments must not be null.
Table({
super.key,
this.children = const <TableRow>[],
this.columnWidths,
this.defaultColumnWidth = const FlexColumnWidth(),
this.textDirection,
this.border,
this.defaultVerticalAlignment = TableCellVerticalAlignment.top,
this.textBaseline, // NO DEFAULT: we don't know what the text's baseline should be
}) : assert(children != null),
assert(defaultColumnWidth != null),
assert(defaultVerticalAlignment != null),
assert(defaultVerticalAlignment != TableCellVerticalAlignment.baseline || textBaseline != null, 'textBaseline is required if you specify the defaultVerticalAlignment with TableCellVerticalAlignment.baseline'),
assert(() {
if (children.any((TableRow row) => row.children == null)) {
throw FlutterError(
'One of the rows of the table had null children.\n'
'The children property of TableRow must not be null.',
);
}
return true;
}()),
assert(() {
if (children.any((TableRow row) => row.children!.any((Widget cell) => cell == null))) {
throw FlutterError(
'One of the children of one of the rows of the table was null.\n'
'The children of a TableRow must not be null.',
);
}
return true;
}()),
assert(() {
if (children.any((TableRow row1) => row1.key != null && children.any((TableRow row2) => row1 != row2 && row1.key == row2.key))) {
throw FlutterError(
'Two or more TableRow children of this Table had the same key.\n'
'All the keyed TableRow children of a Table must have different Keys.',
);
}
return true;
}()),
assert(() {
if (children.isNotEmpty) {
final int cellCount = children.first.children!.length;
if (children.any((TableRow row) => row.children!.length != cellCount)) {
throw FlutterError(
'Table contains irregular row lengths.\n'
'Every TableRow in a Table must have the same number of children, so that every cell is filled. '
'Otherwise, the table will contain holes.',
);
}
}
return true;
}()),
_rowDecorations = children.any((TableRow row) => row.decoration != null)
? children.map<Decoration?>((TableRow row) => row.decoration).toList(growable: false)
: null {
assert(() {
final List<Widget> flatChildren = children.expand<Widget>((TableRow row) => row.children!).toList(growable: false);
return !debugChildrenHaveDuplicateKeys(this, flatChildren, message:
'Two or more cells in this Table contain widgets with the same key.\n'
'Every widget child of every TableRow in a Table must have different keys. The cells of a Table are '
'flattened out for processing, so separate cells cannot have duplicate keys even if they are in '
'different rows.',
);
}());
}
/// The rows of the table.
///
/// Every row in a table must have the same number of children, and all the
/// children must be non-null.
final List<TableRow> children;
/// How the horizontal extents of the columns of this table should be determined.
///
/// If the [Map] has a null entry for a given column, the table uses the
/// [defaultColumnWidth] instead. By default, that uses flex sizing to
/// distribute free space equally among the columns.
///
/// The [FixedColumnWidth] class can be used to specify a specific width in
/// pixels. That is the cheapest way to size a table's columns.
///
/// The layout performance of the table depends critically on which column
/// sizing algorithms are used here. In particular, [IntrinsicColumnWidth] is
/// quite expensive because it needs to measure each cell in the column to
/// determine the intrinsic size of the column.
///
/// The keys of this map (column indexes) are zero-based.
///
/// If this is set to null, then an empty map is assumed.
final Map<int, TableColumnWidth>? columnWidths;
/// How to determine with widths of columns that don't have an explicit sizing
/// algorithm.
///
/// Specifically, the [defaultColumnWidth] is used for column `i` if
/// `columnWidths[i]` is null. Defaults to [FlexColumnWidth], which will
/// divide the remaining horizontal space up evenly between columns of the
/// same type [TableColumnWidth].
///
/// A [Table] in a horizontal [ScrollView] must use a [FixedColumnWidth], or
/// an [IntrinsicColumnWidth] as the horizontal space is infinite.
final TableColumnWidth defaultColumnWidth;
/// The direction in which the columns are ordered.
///
/// Defaults to the ambient [Directionality].
final TextDirection? textDirection;
/// The style to use when painting the boundary and interior divisions of the table.
final TableBorder? border;
/// How cells that do not explicitly specify a vertical alignment are aligned vertically.
///
/// Cells may specify a vertical alignment by wrapping their contents in a
/// [TableCell] widget.
final TableCellVerticalAlignment defaultVerticalAlignment;
/// The text baseline to use when aligning rows using [TableCellVerticalAlignment.baseline].
///
/// This must be set if using baseline alignment. There is no default because there is no
/// way for the framework to know the correct baseline _a priori_.
final TextBaseline? textBaseline;
final List<Decoration?>? _rowDecorations;
@override
RenderObjectElement createElement() => _TableElement(this);
@override
RenderTable createRenderObject(BuildContext context) {
assert(debugCheckHasDirectionality(context));
return RenderTable(
columns: children.isNotEmpty ? children[0].children!.length : 0,
rows: children.length,
columnWidths: columnWidths,
defaultColumnWidth: defaultColumnWidth,
textDirection: textDirection ?? Directionality.of(context),
border: border,
rowDecorations: _rowDecorations,
configuration: createLocalImageConfiguration(context),
defaultVerticalAlignment: defaultVerticalAlignment,
textBaseline: textBaseline,
);
}
@override
void updateRenderObject(BuildContext context, RenderTable renderObject) {
assert(debugCheckHasDirectionality(context));
assert(renderObject.columns == (children.isNotEmpty ? children[0].children!.length : 0));
assert(renderObject.rows == children.length);
renderObject
..columnWidths = columnWidths
..defaultColumnWidth = defaultColumnWidth
..textDirection = textDirection ?? Directionality.of(context)
..border = border
..rowDecorations = _rowDecorations
..configuration = createLocalImageConfiguration(context)
..defaultVerticalAlignment = defaultVerticalAlignment
..textBaseline = textBaseline;
}
}
class _TableElement extends RenderObjectElement {
_TableElement(Table super.widget);
@override
RenderTable get renderObject => super.renderObject as RenderTable;
List<_TableElementRow> _children = const<_TableElementRow>[];
bool _doingMountOrUpdate = false;
@override
void mount(Element? parent, Object? newSlot) {
assert(!_doingMountOrUpdate);
_doingMountOrUpdate = true;
super.mount(parent, newSlot);
int rowIndex = -1;
_children = (widget as Table).children.map<_TableElementRow>((TableRow row) {
int columnIndex = 0;
rowIndex += 1;
return _TableElementRow(
key: row.key,
children: row.children!.map<Element>((Widget child) {
assert(child != null);
return inflateWidget(child, _TableSlot(columnIndex++, rowIndex));
}).toList(growable: false),
);
}).toList(growable: false);
_updateRenderObjectChildren();
assert(_doingMountOrUpdate);
_doingMountOrUpdate = false;
}
@override
void insertRenderObjectChild(RenderBox child, _TableSlot slot) {
renderObject.setupParentData(child);
// Once [mount]/[update] are done, the children are getting set all at once
// in [_updateRenderObjectChildren].
if (!_doingMountOrUpdate) {
renderObject.setChild(slot.column, slot.row, child);
}
}
@override
void moveRenderObjectChild(RenderBox child, _TableSlot oldSlot, _TableSlot newSlot) {
assert(_doingMountOrUpdate);
// Child gets moved at the end of [update] in [_updateRenderObjectChildren].
}
@override
void removeRenderObjectChild(RenderBox child, _TableSlot slot) {
renderObject.setChild(slot.column, slot.row, null);
}
final Set<Element> _forgottenChildren = HashSet<Element>();
@override
void update(Table newWidget) {
assert(!_doingMountOrUpdate);
_doingMountOrUpdate = true;
final Map<LocalKey, List<Element>> oldKeyedRows = <LocalKey, List<Element>>{};
for (final _TableElementRow row in _children) {
if (row.key != null) {
oldKeyedRows[row.key!] = row.children;
}
}
final Iterator<_TableElementRow> oldUnkeyedRows = _children.where((_TableElementRow row) => row.key == null).iterator;
final List<_TableElementRow> newChildren = <_TableElementRow>[];
final Set<List<Element>> taken = <List<Element>>{};
for (int rowIndex = 0; rowIndex < newWidget.children.length; rowIndex++) {
final TableRow row = newWidget.children[rowIndex];
List<Element> oldChildren;
if (row.key != null && oldKeyedRows.containsKey(row.key)) {
oldChildren = oldKeyedRows[row.key]!;
taken.add(oldChildren);
} else if (row.key == null && oldUnkeyedRows.moveNext()) {
oldChildren = oldUnkeyedRows.current.children;
} else {
oldChildren = const <Element>[];
}
final List<_TableSlot> slots = List<_TableSlot>.generate(
row.children!.length,
(int columnIndex) => _TableSlot(columnIndex, rowIndex),
);
newChildren.add(_TableElementRow(
key: row.key,
children: updateChildren(oldChildren, row.children!, forgottenChildren: _forgottenChildren, slots: slots),
));
}
while (oldUnkeyedRows.moveNext()) {
updateChildren(oldUnkeyedRows.current.children, const <Widget>[], forgottenChildren: _forgottenChildren);
}
for (final List<Element> oldChildren in oldKeyedRows.values.where((List<Element> list) => !taken.contains(list))) {
updateChildren(oldChildren, const <Widget>[], forgottenChildren: _forgottenChildren);
}
_children = newChildren;
_updateRenderObjectChildren();
_forgottenChildren.clear();
super.update(newWidget);
assert(widget == newWidget);
assert(_doingMountOrUpdate);
_doingMountOrUpdate = false;
}
void _updateRenderObjectChildren() {
assert(renderObject != null);
renderObject.setFlatChildren(
_children.isNotEmpty ? _children[0].children.length : 0,
_children.expand<RenderBox>((_TableElementRow row) {
return row.children.map<RenderBox>((Element child) {
final RenderBox box = child.renderObject! as RenderBox;
return box;
});
}).toList(),
);
}
@override
void visitChildren(ElementVisitor visitor) {
for (final Element child in _children.expand<Element>((_TableElementRow row) => row.children)) {
if (!_forgottenChildren.contains(child)) {
visitor(child);
}
}
}
@override
bool forgetChild(Element child) {
_forgottenChildren.add(child);
super.forgetChild(child);
return true;
}
}
/// A widget that controls how a child of a [Table] is aligned.
///
/// A [TableCell] widget must be a descendant of a [Table], and the path from
/// the [TableCell] widget to its enclosing [Table] must contain only
/// [TableRow]s, [StatelessWidget]s, or [StatefulWidget]s (not
/// other kinds of widgets, like [RenderObjectWidget]s).
class TableCell extends ParentDataWidget<TableCellParentData> {
/// Creates a widget that controls how a child of a [Table] is aligned.
const TableCell({
super.key,
this.verticalAlignment,
required super.child,
});
/// How this cell is aligned vertically.
final TableCellVerticalAlignment? verticalAlignment;
@override
void applyParentData(RenderObject renderObject) {
final TableCellParentData parentData = renderObject.parentData! as TableCellParentData;
if (parentData.verticalAlignment != verticalAlignment) {
parentData.verticalAlignment = verticalAlignment;
final AbstractNode? targetParent = renderObject.parent;
if (targetParent is RenderObject) {
targetParent.markNeedsLayout();
}
}
}
@override
Type get debugTypicalAncestorWidgetClass => Table;
@override
void debugFillProperties(DiagnosticPropertiesBuilder properties) {
super.debugFillProperties(properties);
properties.add(EnumProperty<TableCellVerticalAlignment>('verticalAlignment', verticalAlignment));
}
}
@immutable
class _TableSlot with Diagnosticable {
const _TableSlot(this.column, this.row);
final int column;
final int row;
@override
bool operator ==(Object other) {
if (other.runtimeType != runtimeType) {
return false;
}
return other is _TableSlot
&& column == other.column
&& row == other.row;
}
@override
int get hashCode => Object.hash(column, row);
@override
void debugFillProperties(DiagnosticPropertiesBuilder properties) {
super.debugFillProperties(properties);
properties.add(IntProperty('x', column));
properties.add(IntProperty('y', row));
}
}