feat: refactor keyboard height observer to support multiple listeners (…

…AppFlowy-IO#602)

lib/src/editor/toolbar/mobile/mobile_toolbar_v2.dart

@@ -1,6 +1,8 @@
 import 'package:appflowy_editor/appflowy_editor.dart';
+import 'package:appflowy_editor/src/editor/toolbar/mobile/utils/keyboard_height_observer.dart';
 import 'package:flutter/material.dart';
-import 'package:keyboard_height_plugin/keyboard_height_plugin.dart';
+
+const String disableMobileToolbarKey = 'disableMobileToolbar';
 
 class MobileToolbarV2 extends StatefulWidget {
   const MobileToolbarV2({
@@ -56,23 +58,21 @@ class MobileToolbarV2 extends StatefulWidget {
 
 class _MobileToolbarV2State extends State<MobileToolbarV2> {
   OverlayEntry? toolbarOverlay;
-  final keyboardHeightPlugin = KeyboardHeightPlugin();
+
   final isKeyboardShow = ValueNotifier(false);
 
   @override
   void initState() {
     super.initState();
 
     _insertKeyboardToolbar();
-    keyboardHeightPlugin.onKeyboardHeightChanged((height) {
-      isKeyboardShow.value = height > 0;
-    });
+    KeyboardHeightObserver.instance.addListener(_onKeyboardHeightChanged);
   }
 
   @override
   void dispose() {
     _removeKeyboardToolbar();
-    keyboardHeightPlugin.dispose();
+    KeyboardHeightObserver.instance.removeListener(_onKeyboardHeightChanged);
 
     super.dispose();
   }
@@ -97,6 +97,10 @@ class _MobileToolbarV2State extends State<MobileToolbarV2> {
     );
   }
 
+  void _onKeyboardHeightChanged(double height) {
+    isKeyboardShow.value = height > 0;
+  }
+
   void _removeKeyboardToolbar() {
     toolbarOverlay?.remove();
     toolbarOverlay?.dispose();
@@ -110,7 +114,9 @@ class _MobileToolbarV2State extends State<MobileToolbarV2> {
       valueListenable: widget.editorState.selectionNotifier,
       builder: (_, Selection? selection, __) {
         // if the selection is null, hide the toolbar
-        if (selection == null) {
+        if (selection == null ||
+            widget.editorState.selectionExtraInfo?[disableMobileToolbarKey] ==
+                true) {
           return const SizedBox.shrink();
         }
 
@@ -190,7 +196,6 @@ class _MobileToolbarState extends State<_MobileToolbar>
   // This is because we want to keep the same height when the menu is shown.
   bool canUpdateCachedKeyboardHeight = true;
   ValueNotifier<double> cachedKeyboardHeight = ValueNotifier(0.0);
-  final keyboardHeightPlugin = KeyboardHeightPlugin();
 
   // used to check if click the same item again
   int? selectedMenuIndex;
@@ -202,11 +207,7 @@ class _MobileToolbarState extends State<_MobileToolbar>
     super.initState();
 
     currentSelection = widget.editorState.selection;
-    keyboardHeightPlugin.onKeyboardHeightChanged((height) {
-      if (canUpdateCachedKeyboardHeight) {
-        cachedKeyboardHeight.value = height;
-      }
-    });
+    KeyboardHeightObserver.instance.addListener(_onKeyboardHeightChanged);
   }
 
   @override
@@ -223,7 +224,7 @@ class _MobileToolbarState extends State<_MobileToolbar>
   void dispose() {
     showMenuNotifier.dispose();
     cachedKeyboardHeight.dispose();
-    keyboardHeightPlugin.dispose();
+    KeyboardHeightObserver.instance.removeListener(_onKeyboardHeightChanged);
 
     super.dispose();
   }
@@ -259,6 +260,12 @@ class _MobileToolbarState extends State<_MobileToolbar>
     showMenuNotifier.value = true;
   }
 
+  void _onKeyboardHeightChanged(double height) {
+    if (canUpdateCachedKeyboardHeight) {
+      cachedKeyboardHeight.value = height;
+    }
+  }
+
   // toolbar list view and close keyboard/menu button
   Widget _buildToolbar(BuildContext context) {
     final width = MediaQuery.of(context).size.width;

lib/src/editor/toolbar/mobile/utils/keyboard_height_observer.dart

@@ -0,0 +1,37 @@
+import 'package:keyboard_height_plugin/keyboard_height_plugin.dart';
+
+typedef KeyboardHeightCallback = void Function(double height);
+
+// the KeyboardHeightPlugin only accepts one listener, so we need to create a
+//  singleton class to manage the multiple listeners.
+class KeyboardHeightObserver {
+  KeyboardHeightObserver._() {
+    _keyboardHeightPlugin.onKeyboardHeightChanged((height) {
+      notify(height);
+    });
+  }
+
+  static final KeyboardHeightObserver instance = KeyboardHeightObserver._();
+
+  final List<KeyboardHeightCallback> _listeners = [];
+  final KeyboardHeightPlugin _keyboardHeightPlugin = KeyboardHeightPlugin();
+
+  void addListener(KeyboardHeightCallback listener) {
+    _listeners.add(listener);
+  }
+
+  void removeListener(KeyboardHeightCallback listener) {
+    _listeners.remove(listener);
+  }
+
+  void dispose() {
+    _listeners.clear();
+    _keyboardHeightPlugin.dispose();
+  }
+
+  void notify(double height) {
+    for (final listener in _listeners) {
+      listener(height);
+    }
+  }
+}