updating checkbox to handle tap

lib/widgets/editor.dart

@@ -393,8 +393,6 @@ class _QuillEditorSelectionGestureDetectorBuilder
     final segmentResult = line.queryChild(result.offset, false);
     if (segmentResult.node == null) {
       if (line.length == 1) {
-        // tapping when no text yet on this line
-        _flipListCheckbox(pos, line, segmentResult);
         getEditor()!.widget.controller.updateSelection(
             TextSelection.collapsed(offset: pos.offset), ChangeSource.LOCAL);
         return true;
@@ -434,37 +432,9 @@ class _QuillEditorSelectionGestureDetectorBuilder
           ),
         );
       }
-      return false;
-    }
-    if (_flipListCheckbox(pos, line, segmentResult)) {
-      return true;
     }
-    return false;
-  }
 
-  bool _flipListCheckbox(
-      TextPosition pos, Line line, container_node.ChildQuery segmentResult) {
-    if (getEditor()!.widget.readOnly ||
-        !line.style.containsKey(Attribute.list.key) ||
-        segmentResult.offset != 0) {
-      return false;
-    }
-    // segmentResult.offset == 0 means tap at the beginning of the TextLine
-    final String? listVal = line.style.attributes[Attribute.list.key]!.value;
-    if (listVal == Attribute.unchecked.value) {
-      getEditor()!
-          .widget
-          .controller
-          .formatText(pos.offset, 0, Attribute.checked);
-    } else if (listVal == Attribute.checked.value) {
-      getEditor()!
-          .widget
-          .controller
-          .formatText(pos.offset, 0, Attribute.unchecked);
-    }
-    getEditor()!.widget.controller.updateSelection(
-        TextSelection.collapsed(offset: pos.offset), ChangeSource.LOCAL);
-    return true;
+    return false;
   }
 
   Future<void> _launchUrl(String url) async {

lib/widgets/raw_editor.dart

@@ -579,6 +579,18 @@ class RawEditorState extends EditorState
     }
   }
 
+  /// Updates the checkbox positioned at [offset] in document
+  /// by changing its attribute according to [value].
+  void _handleCheckboxTap(int offset, bool value) {
+    if (!widget.readOnly) {
+      if (value) {
+        widget.controller.formatText(offset, 0, Attribute.checked);
+      } else {
+        widget.controller.formatText(offset, 0, Attribute.unchecked);
+      }
+    }
+  }
+
   List<Widget> _buildChildren(Document doc, BuildContext context) {
     final result = <Widget>[];
     final indentLevelCounts = <int, int>{};
@@ -589,21 +601,23 @@ class RawEditorState extends EditorState
       } else if (node is Block) {
         final attrs = node.style.attributes;
         final editableTextBlock = EditableTextBlock(
-            node,
-            _textDirection,
-            widget.scrollBottomInset,
-            _getVerticalSpacingForBlock(node, _styles),
-            widget.controller.selection,
-            widget.selectionColor,
-            _styles,
-            widget.enableInteractiveSelection,
-            _hasFocus,
-            attrs.containsKey(Attribute.codeBlock.key)
-                ? const EdgeInsets.all(16)
-                : null,
-            widget.embedBuilder,
-            _cursorCont,
-            indentLevelCounts);
+          node,
+          _textDirection,
+          widget.scrollBottomInset,
+          _getVerticalSpacingForBlock(node, _styles),
+          widget.controller.selection,
+          widget.selectionColor,
+          _styles,
+          widget.enableInteractiveSelection,
+          _hasFocus,
+          attrs.containsKey(Attribute.codeBlock.key)
+              ? const EdgeInsets.all(16)
+              : null,
+          widget.embedBuilder,
+          _cursorCont,
+          indentLevelCounts,
+          _handleCheckboxTap,
+        );
         result.add(editableTextBlock);
       } else {
         throw StateError('Unreachable.');

lib/widgets/text_block.dart

@@ -61,6 +61,7 @@ class EditableTextBlock extends StatelessWidget {
     this.embedBuilder,
     this.cursorCont,
     this.indentLevelCounts,
+    this.onCheckboxTap,
   );
 
   final Block block;
@@ -76,6 +77,7 @@ class EditableTextBlock extends StatelessWidget {
   final EmbedBuilder embedBuilder;
   final CursorCont cursorCont;
   final Map<int, int> indentLevelCounts;
+  final Function(int, bool) onCheckboxTap;
 
   @override
   Widget build(BuildContext context) {
@@ -161,12 +163,22 @@ class EditableTextBlock extends StatelessWidget {
 
     if (attrs[Attribute.list.key] == Attribute.checked) {
       return _Checkbox(
-          style: defaultStyles!.leading!.style, width: 32, isChecked: true);
+        style: defaultStyles!.leading!.style,
+        width: 32,
+        isChecked: true,
+        offset: block.offset + line.offset,
+        onTap: onCheckboxTap,
+      );
     }
 
     if (attrs[Attribute.list.key] == Attribute.unchecked) {
       return _Checkbox(
-          style: defaultStyles!.leading!.style, width: 32, isChecked: false);
+        style: defaultStyles!.leading!.style,
+        width: 32,
+        isChecked: false,
+        offset: block.offset + line.offset,
+        onTap: onCheckboxTap,
+      );
     }
 
     if (attrs.containsKey(Attribute.codeBlock.key)) {
@@ -685,45 +697,38 @@ class _BulletPoint extends StatelessWidget {
   }
 }
 
-class _Checkbox extends StatefulWidget {
-  const _Checkbox({Key? key, this.style, this.width, this.isChecked})
-      : super(key: key);
+/// A Checkbox widget.
+class _Checkbox extends StatelessWidget {
+  /// Creates a [_Checkbox].
+  const _Checkbox({
+    Key? key,
+    this.style,
+    this.width,
+    this.isChecked,
+    this.offset,
+    this.onTap,
+  }) : super(key: key);
 
   final TextStyle? style;
   final double? width;
   final bool? isChecked;
+  final int? offset;
+  final Function(int, bool)? onTap;
 
-  @override
-  __CheckboxState createState() => __CheckboxState();
-}
-
-class __CheckboxState extends State<_Checkbox> {
-  bool? isChecked;
-
-  void _onCheckboxClicked(bool? newValue) => setState(() {
-        isChecked = newValue;
-
-        if (isChecked!) {
-          // check list
-        } else {
-          // uncheck list
-        }
-      });
-
-  @override
-  void initState() {
-    super.initState();
-    isChecked = widget.isChecked;
+  void _onCheckboxClicked(bool? newValue) {
+    if (onTap != null && newValue != null && offset != null) {
+      onTap!(offset!, newValue);
+    }
   }
 
   @override
   Widget build(BuildContext context) {
     return Container(
       alignment: AlignmentDirectional.topEnd,
-      width: widget.width,
+      width: width,
       padding: const EdgeInsetsDirectional.only(end: 13),
       child: Checkbox(
-        value: widget.isChecked,
+        value: isChecked,
         onChanged: _onCheckboxClicked,
       ),
     );