- fixed showToolbar: ensure selectionOverlay is available

- fixed _getSpacingForLine: ensure lineSpacing has a value
- fixed bringIntoView: doesn't throw exception when position is invalid
- code cleanup (remove warnings)

lib/flutter_quill.dart

@@ -6,9 +6,9 @@ export 'src/models/documents/nodes/embeddable.dart';
 export 'src/models/documents/nodes/leaf.dart';
 export 'src/models/documents/style.dart';
 export 'src/models/quill_delta.dart';
+export 'src/models/themes/quill_custom_icon.dart';
 export 'src/models/themes/quill_dialog_theme.dart';
 export 'src/models/themes/quill_icon_theme.dart';
-export 'src/models/themes/quill_custom_icon.dart';
 export 'src/widgets/controller.dart';
 export 'src/widgets/default_styles.dart';
 export 'src/widgets/editor.dart';

lib/src/widgets/raw_editor.dart

@@ -896,6 +896,14 @@ class RawEditorState extends EditorState
     if (kIsWeb) {
       return false;
     }
+
+    // selectionOverlay is aggressively released when selection is collapsed
+    // to remove unnecessary handles. Since a toolbar is requested here,
+    // attempt to create the selectionOverlay if it's not already created.
+    if (_selectionOverlay == null) {
+      _updateOrDisposeSelectionOverlayIfNeeded();
+    }
+
     if (_selectionOverlay == null || _selectionOverlay!.toolbar != null) {
       return false;
     }

lib/src/widgets/raw_editor/raw_editor_state_selection_delegate_mixin.dart

@@ -71,13 +71,18 @@ mixin RawEditorStateSelectionDelegateMixin on EditorState
 
   @override
   void bringIntoView(TextPosition position) {
-    final localRect = renderEditor.getLocalRectForCaret(position);
-    final targetOffset = _getOffsetToRevealCaret(localRect, position);
-
-    if (scrollController.hasClients) {
-      scrollController.jumpTo(targetOffset.offset);
+    // Ignore errors if position is invalid (i.e. paste on iOS when editor
+    // has no content and user pasted from toolbar)
+    try {
+      final localRect = renderEditor.getLocalRectForCaret(position);
+      final targetOffset = _getOffsetToRevealCaret(localRect, position);
+
+      if (scrollController.hasClients) {
+        scrollController.jumpTo(targetOffset.offset);
+      }
+      renderEditor.showOnScreen(rect: targetOffset.rect);
+    } catch (_) {
     }
-    renderEditor.showOnScreen(rect: targetOffset.rect);
   }
 
   // Finds the closest scroll offset to the current scroll offset that fully

lib/src/widgets/text_block.dart

@@ -272,6 +272,9 @@ class EditableTextBlock extends StatelessWidget {
         lineSpacing = defaultStyles!.code!.lineSpacing;
       } else if (attrs.containsKey(Attribute.align.key)) {
         lineSpacing = defaultStyles!.align!.lineSpacing;
+      } else {
+        // use paragraph linespacing as a default
+        lineSpacing = defaultStyles!.paragraph!.lineSpacing;
       }
       top = lineSpacing.item1;
       bottom = lineSpacing.item2;

lib/src/widgets/toolbar.dart

@@ -4,9 +4,9 @@ import 'package:flutter/material.dart';
 import 'package:i18n_extension/i18n_widget.dart';
 
 import '../models/documents/attribute.dart';
+import '../models/themes/quill_custom_icon.dart';
 import '../models/themes/quill_dialog_theme.dart';
 import '../models/themes/quill_icon_theme.dart';
-import '../models/themes/quill_custom_icon.dart';
 import 'controller.dart';
 import 'toolbar/arrow_indicated_button_list.dart';
 import 'toolbar/camera_button.dart';
@@ -17,13 +17,13 @@ import 'toolbar/image_button.dart';
 import 'toolbar/image_video_utils.dart';
 import 'toolbar/indent_button.dart';
 import 'toolbar/link_style_button.dart';
+import 'toolbar/quill_dropdown_button.dart';
+import 'toolbar/quill_icon_button.dart';
 import 'toolbar/select_alignment_button.dart';
 import 'toolbar/select_header_style_button.dart';
 import 'toolbar/toggle_check_list_button.dart';
 import 'toolbar/toggle_style_button.dart';
 import 'toolbar/video_button.dart';
-import 'toolbar/quill_dropdown_button.dart';
-import 'toolbar/quill_icon_button.dart';
 
 export 'toolbar/clear_format_button.dart';
 export 'toolbar/color_button.dart';

lib/src/widgets/toolbar/quill_dropdown_button.dart

@@ -1,7 +1,8 @@
 import 'package:flutter/material.dart';
-import '../../models/themes/quill_icon_theme.dart';
-import '../../models/documents/style.dart';
+
 import '../../models/documents/attribute.dart';
+import '../../models/documents/style.dart';
+import '../../models/themes/quill_icon_theme.dart';
 import '../controller.dart';
 
 class QuillDropdownButton<T> extends StatefulWidget {
@@ -92,7 +93,7 @@ class _QuillDropdownButtonState<T> extends State<QuillDropdownButton<T>> {
   @override
   Widget build(BuildContext context) {
     return ConstrainedBox(
-      constraints: BoxConstraints.tightFor(height: (widget.iconSize * 1.81)),
+      constraints: BoxConstraints.tightFor(height: widget.iconSize * 1.81),
       child: RawMaterialButton(
         visualDensity: VisualDensity.compact,
         shape: RoundedRectangleBorder(
@@ -160,7 +161,7 @@ class _QuillDropdownButtonState<T> extends State<QuillDropdownButton<T>> {
                   fontSize: widget.iconSize / 1.15,
                   color: widget.iconTheme?.iconUnselectedColor ??
                       theme.iconTheme.color)),
-          SizedBox(width: 3),
+          const SizedBox(width: 3),
           Icon(Icons.arrow_drop_down,
               size: widget.iconSize / 1.15,
               color: widget.iconTheme?.iconUnselectedColor ??