recent dms [nfc]: Allow onDmSelect callback, notifying the selected DM

This will be used soon to provide a specific behaviour when
selecting a DM, where if specified it will replace the default
behaviour of routing to the message list page of the selected DM
narrow.

Author: rajveermalviya

lib/widgets/new_dm_sheet.dart

@@ -8,12 +8,13 @@ import 'color.dart';
 import 'icons.dart';
 import 'message_list.dart';
 import 'page.dart';
+import 'recent_dm_conversations.dart';
 import 'store.dart';
 import 'text.dart';
 import 'theme.dart';
 import 'user.dart';
 
-void showNewDmSheet(BuildContext context) {
+void showNewDmSheet(BuildContext context, OnDmSelectCallback? onDmSelect) {
   final pageContext = PageRoot.contextOf(context);
   final store = PerAccountStoreWidget.of(context);
   showModalBottomSheet<void>(
@@ -29,12 +30,14 @@ void showNewDmSheet(BuildContext context) {
       padding: EdgeInsets.only(bottom: MediaQuery.viewInsetsOf(context).bottom),
       child: PerAccountStoreWidget(
         accountId: store.accountId,
-        child: NewDmPicker())));
+        child: NewDmPicker(onDmSelect: onDmSelect))));
 }
 
 @visibleForTesting
 class NewDmPicker extends StatefulWidget {
-  const NewDmPicker({super.key});
+  const NewDmPicker({super.key, this.onDmSelect});
+
+  final OnDmSelectCallback? onDmSelect;
 
   @override
   State<NewDmPicker> createState() => _NewDmPickerState();
@@ -132,7 +135,7 @@ class _NewDmPickerState extends State<NewDmPicker> with PerAccountStoreAwareStat
   @override
   Widget build(BuildContext context) {
     return Column(crossAxisAlignment: CrossAxisAlignment.stretch, children: [
-      _NewDmHeader(selectedUserIds: selectedUserIds),
+      _NewDmHeader(selectedUserIds: selectedUserIds, onDmSelect: widget.onDmSelect),
       _NewDmSearchBar(
         controller: searchController,
         selectedUserIds: selectedUserIds,
@@ -148,9 +151,10 @@ class _NewDmPickerState extends State<NewDmPicker> with PerAccountStoreAwareStat
 }
 
 class _NewDmHeader extends StatelessWidget {
-  const _NewDmHeader({required this.selectedUserIds});
+  const _NewDmHeader({required this.selectedUserIds, required this.onDmSelect});
 
   final Set<int> selectedUserIds;
+  final OnDmSelectCallback? onDmSelect;
 
   Widget _buildCancelButton(BuildContext context) {
     final designVariables = DesignVariables.of(context);
@@ -178,8 +182,14 @@ class _NewDmHeader extends StatelessWidget {
         final narrow = DmNarrow.withUsers(
           selectedUserIds.toList(),
           selfUserId: store.selfUserId);
-        Navigator.pushReplacement(context,
-          MessageListPage.buildRoute(context: context, narrow: narrow));
+        if (onDmSelect != null) {
+          // Pop the new DMs action sheet.
+          Navigator.pop(context);
+          onDmSelect!(context, narrow);
+        } else {
+          Navigator.pushReplacement(context,
+            MessageListPage.buildRoute(context: context, narrow: narrow));
+        }
       },
       child: Text(zulipLocalizations.newDmSheetComposeButtonLabel,
         style: TextStyle(

lib/widgets/recent_dm_conversations.dart

@@ -14,13 +14,17 @@ import 'theme.dart';
 import 'unread_count_badge.dart';
 import 'user.dart';
 
+typedef OnDmSelectCallback = void Function(BuildContext context, DmNarrow narrow);
+
 class RecentDmConversationsPageBody extends StatefulWidget {
   const RecentDmConversationsPageBody({
     super.key,
     this.hideDmsIfUserCantPost = false,
+    this.onDmSelect,
   });
 
   final bool hideDmsIfUserCantPost;
+  final OnDmSelectCallback? onDmSelect;
 
   @override
   State<RecentDmConversationsPageBody> createState() => _RecentDmConversationsPageBodyState();
@@ -91,11 +95,17 @@ class _RecentDmConversationsPageBodyState extends State<RecentDmConversationsPag
                 }
                 return RecentDmConversationsItem(
                   narrow: narrow,
-                  unreadCount: unreadsModel!.countInDmNarrow(narrow));
+                  unreadCount: unreadsModel!.countInDmNarrow(narrow),
+                  onDmSelect: widget.onDmSelect
+                    ?? (context, narrow) {
+                      Navigator.push(context,
+                        MessageListPage.buildRoute(context: context,
+                          narrow: narrow));
+                    });
               })),
         Positioned(
           bottom: 21,
-          child: _NewDmButton()),
+          child: _NewDmButton(onDmSelect: widget.onDmSelect)),
       ]);
   }
 }
@@ -105,10 +115,12 @@ class RecentDmConversationsItem extends StatelessWidget {
     super.key,
     required this.narrow,
     required this.unreadCount,
+    required this.onDmSelect,
   });
 
   final DmNarrow narrow;
   final int unreadCount;
+  final OnDmSelectCallback onDmSelect;
 
   static const double _avatarSize = 32;
 
@@ -151,10 +163,7 @@ class RecentDmConversationsItem extends StatelessWidget {
     return Material(
       color: backgroundColor,
       child: InkWell(
-        onTap: () {
-          Navigator.push(context,
-            MessageListPage.buildRoute(context: context, narrow: narrow));
-        },
+        onTap: () => onDmSelect(context, narrow),
         child: ConstrainedBox(constraints: const BoxConstraints(minHeight: 48),
           child: Row(crossAxisAlignment: CrossAxisAlignment.center, children: [
             Padding(padding: const EdgeInsetsDirectional.fromSTEB(12, 8, 0, 8),
@@ -188,7 +197,11 @@ class RecentDmConversationsItem extends StatelessWidget {
 }
 
 class _NewDmButton extends StatefulWidget {
-  const _NewDmButton();
+  const _NewDmButton({
+    required this.onDmSelect,
+  });
+
+  final OnDmSelectCallback? onDmSelect;
 
   @override
   State<_NewDmButton> createState() => _NewDmButtonState();
@@ -210,7 +223,7 @@ class _NewDmButtonState extends State<_NewDmButton> {
       : designVariables.fabLabel;
 
     return GestureDetector(
-      onTap: () => showNewDmSheet(context),
+      onTap: () => showNewDmSheet(context, widget.onDmSelect),
       onTapDown: (_) => setState(() => _pressed = true),
       onTapUp: (_) => setState(() => _pressed = false),
       onTapCancel: () => setState(() => _pressed = false),