flutter-quill/lib/src/widgets/toolbar/link_style_button.dart

import 'package:flutter/material.dart';

import '../../models/documents/attribute.dart';
import '../controller.dart';
import '../link_dialog.dart';
import '../toolbar.dart';
import 'quill_icon_button.dart';

class LinkStyleButton extends StatefulWidget {
  const LinkStyleButton({
    required this.controller,
    this.iconSize = kDefaultIconSize,
    this.icon,
    Key? key,
  }) : super(key: key);

  final QuillController controller;
  final IconData? icon;
  final double iconSize;

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

class _LinkStyleButtonState extends State<LinkStyleButton> {
  void _didChangeSelection() {
    setState(() {});
  }

  @override
  void initState() {
    super.initState();
    widget.controller.addListener(_didChangeSelection);
  }

  @override
  void didUpdateWidget(covariant LinkStyleButton oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.controller != widget.controller) {
      oldWidget.controller.removeListener(_didChangeSelection);
      widget.controller.addListener(_didChangeSelection);
    }
  }

  @override
  void dispose() {
    super.dispose();
    widget.controller.removeListener(_didChangeSelection);
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final isEnabled = !widget.controller.selection.isCollapsed;
    final pressedHandler = isEnabled ? () => _openLinkDialog(context) : null;
    return QuillIconButton(
      highlightElevation: 0,
      hoverElevation: 0,
      size: widget.iconSize * kIconButtonFactor,
      icon: Icon(
        widget.icon ?? Icons.link,
        size: widget.iconSize,
        color: isEnabled ? theme.iconTheme.color : theme.disabledColor,
      ),
      fillColor: Theme.of(context).canvasColor,
      onPressed: pressedHandler,
    );
  }

  void _openLinkDialog(BuildContext context) {
    showDialog<String>(
      context: context,
      builder: (ctx) {
        return const LinkDialog();
      },
    ).then(_linkSubmitted);
  }

  void _linkSubmitted(String? value) {
    if (value == null || value.isEmpty) {
      return;
    }
    widget.controller.formatSelection(LinkAttribute(value));
  }
}