custom_menu_page.dart

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/services.dart';
import 'package:flutter/widgets.dart';
import 'app_scaffold.dart';

class _TextSelectionToolbarItemData {
  const _TextSelectionToolbarItemData({
    this.label,
    this.onPressed,
  });

  final String label;
  final VoidCallback onPressed;
}

class CustomMenuPage extends StatefulWidget {
  const CustomMenuPage({ Key key }) : super(key: key);

  static const String routeName = '/custom-menu';

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

class _CustomMenuPageState extends State<CustomMenuPage> {
  @override
  Widget build(BuildContext context) {
    return AppScaffold(
      title: 'Custom Menu Page',
      /*
      child: TextField(
        maxLines: 5,
        selectionControls: MyMaterialTextSelectionControls(),
      ),
      */
      child: SelectableText(
        'Select me custom menu',
        selectionControls: MyMaterialTextSelectionControls(),
      ),
    );
  }
}

class MyMaterialTextSelectionControls extends MaterialTextSelectionControls {
  // Padding between the toolbar and the anchor.
  static const double _kToolbarContentDistanceBelow = 20.0;
  static const double _kToolbarContentDistance = 8.0;

  /// Builder for material-style copy/paste text selection toolbar.
  @override
  Widget buildToolbar(
    BuildContext context,
    Rect globalEditableRegion,
    double textLineHeight,
    Offset selectionMidpoint,
    List<TextSelectionPoint> endpoints,
    TextSelectionDelegate delegate,
    ClipboardStatusNotifier clipboardStatus,
    Offset lastSecondaryTapDownPosition,
  ) {
    final TextSelectionPoint startTextSelectionPoint = endpoints[0];
    final TextSelectionPoint endTextSelectionPoint = endpoints.length > 1
      ? endpoints[1]
      : endpoints[0];
    final Offset anchorAbove = Offset(
      globalEditableRegion.left + selectionMidpoint.dx,
      globalEditableRegion.top + startTextSelectionPoint.point.dy - textLineHeight - _kToolbarContentDistance
    );
    final Offset anchorBelow = Offset(
      globalEditableRegion.left + selectionMidpoint.dx,
      globalEditableRegion.top + endTextSelectionPoint.point.dy + _kToolbarContentDistanceBelow,
    );

    return MyTextSelectionToolbar(
      anchorAbove: anchorAbove,
      anchorBelow: anchorBelow,
      clipboardStatus: clipboardStatus,
      handleCopy: canCopy(delegate) && handleCopy != null ? () => handleCopy(delegate, clipboardStatus) : null,
      handleCustomButton: () {
        delegate.textEditingValue = delegate.textEditingValue.copyWith(
          selection: TextSelection.collapsed(
            offset: delegate.textEditingValue.selection.baseOffset,
          ),
        );
        delegate.hideToolbar();
      },
      handleCut: canCut(delegate) && handleCut != null ? () => handleCut(delegate) : null,
      handlePaste: canPaste(delegate) && handlePaste != null ? () => handlePaste(delegate) : null,
      handleSelectAll: canSelectAll(delegate) && handleSelectAll != null ? () => handleSelectAll(delegate) : null,
    );
  }
}

class MyTextSelectionToolbar extends StatefulWidget {
  const MyTextSelectionToolbar({
    Key key,
    this.anchorAbove,
    this.anchorBelow,
    this.clipboardStatus,
    this.handleCopy,
    this.handleCustomButton,
    this.handleCut,
    this.handlePaste,
    this.handleSelectAll,
  }) : super(key: key);

  final Offset anchorAbove;
  final Offset anchorBelow;
  final ClipboardStatusNotifier clipboardStatus;
  final VoidCallback handleCopy;
  final VoidCallback handleCustomButton;
  final VoidCallback handleCut;
  final VoidCallback handlePaste;
  final VoidCallback handleSelectAll;

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

class MyTextSelectionToolbarState extends State<MyTextSelectionToolbar> {
  void _onChangedClipboardStatus() {
    setState(() {
      // Inform the widget that the value of clipboardStatus has changed.
    });
  }

  @override
  void initState() {
    super.initState();
    widget.clipboardStatus.addListener(_onChangedClipboardStatus);
    widget.clipboardStatus.update();
  }

  @override
  void didUpdateWidget(MyTextSelectionToolbar oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (widget.clipboardStatus != oldWidget.clipboardStatus) {
      widget.clipboardStatus.addListener(_onChangedClipboardStatus);
      oldWidget.clipboardStatus.removeListener(_onChangedClipboardStatus);
    }
    widget.clipboardStatus.update();
  }

  @override
  void dispose() {
    super.dispose();
    if (!widget.clipboardStatus.disposed) {
      widget.clipboardStatus.removeListener(_onChangedClipboardStatus);
    }
  }

  @override
  Widget build(BuildContext context) {
    assert(debugCheckHasMaterialLocalizations(context));
    final MaterialLocalizations localizations = MaterialLocalizations.of(context);

    final List<_TextSelectionToolbarItemData> itemDatas = <_TextSelectionToolbarItemData>[
      if (widget.handleCut != null)
        _TextSelectionToolbarItemData(
          label: localizations.cutButtonLabel,
          onPressed: widget.handleCut,
        ),
      if (widget.handleCopy != null)
        _TextSelectionToolbarItemData(
          label: localizations.copyButtonLabel,
          onPressed: widget.handleCopy,
        ),
      if (widget.handlePaste != null
          && widget.clipboardStatus.value == ClipboardStatus.pasteable)
        _TextSelectionToolbarItemData(
          label: localizations.pasteButtonLabel,
          onPressed: widget.handlePaste,
        ),
      if (widget.handleSelectAll != null)
        _TextSelectionToolbarItemData(
          label: localizations.selectAllButtonLabel,
          onPressed: widget.handleSelectAll,
        ),
      _TextSelectionToolbarItemData(
        onPressed: widget.handleCustomButton,
        label: 'Custom button',
      ),
    ];

    int childIndex = 0;
    return TextSelectionToolbar(
      anchorAbove: widget.anchorAbove,
      anchorBelow: widget.anchorBelow,
      toolbarBuilder: (BuildContext context, Widget child) {
        return Container(
          color: Colors.pink,
          child: child,
        );
      },
      children: itemDatas.map((_TextSelectionToolbarItemData itemData) {
        return TextSelectionToolbarTextButton(
          padding: TextSelectionToolbarTextButton.getPadding(childIndex++, itemDatas.length),
          onPressed: itemData.onPressed,
          child: Text(itemData.label),
        );
      }).toList(),
    );
  }
}