refactor: Make more widgets null safe

lib/widgets/adaptive_flat_button.dart

@@ -1,3 +1,5 @@
+//@dart=2.12
+
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 
@@ -5,12 +7,12 @@ import 'package:fluffychat/utils/platform_infos.dart';
 
 class AdaptiveFlatButton extends StatelessWidget {
   final String label;
-  final Color textColor;
+  final Color? textColor;
-  final Function onPressed;
+  final void Function()? onPressed;
 
   const AdaptiveFlatButton({
-    Key key,
+    Key? key,
-    @required this.label,
+    required this.label,
     this.textColor,
     this.onPressed,
   }) : super(key: key);

lib/widgets/avatar.dart

@@ -1,3 +1,5 @@
+//@dart=2.12
+
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 
@@ -8,12 +10,12 @@ import 'package:fluffychat/utils/string_color.dart';
 import 'matrix.dart';
 
 class Avatar extends StatelessWidget {
-  final Uri mxContent;
+  final Uri? mxContent;
-  final String name;
+  final String? name;
   final double size;
-  final Function onTap;
+  final void Function()? onTap;
   static const double defaultSize = 44;
-  final Client client;
+  final Client? client;
   final double fontSize;
 
   const Avatar(
@@ -23,7 +25,7 @@ class Avatar extends StatelessWidget {
     this.onTap,
     this.client,
     this.fontSize = 18,
-    Key key,
+    Key? key,
   }) : super(key: key);
 
   @override
@@ -34,11 +36,14 @@ class Avatar extends StatelessWidget {
       height: size * MediaQuery.of(context).devicePixelRatio,
     );
     var fallbackLetters = '@';
-    if ((name?.runes?.length ?? 0) >= 2) {
+    final name = this.name;
+    if (name != null) {
+      if (name.runes.length >= 2) {
         fallbackLetters = String.fromCharCodes(name.runes, 0, 2);
-    } else if ((name?.runes?.length ?? 0) == 1) {
+      } else if (name.runes.length == 1) {
         fallbackLetters = name;
       }
+    }
     final noPic = mxContent == null ||
         mxContent.toString().isEmpty ||
         mxContent.toString() == 'null';

lib/widgets/chat_settings_popup_menu.dart

@@ -1,3 +1,5 @@
+//@dart=2.12
+
 import 'dart:async';
 
 import 'package:flutter/material.dart';
@@ -13,7 +15,7 @@ import 'matrix.dart';
 class ChatSettingsPopupMenu extends StatefulWidget {
   final Room room;
   final bool displayChatDetails;
-  const ChatSettingsPopupMenu(this.room, this.displayChatDetails, {Key key})
+  const ChatSettingsPopupMenu(this.room, this.displayChatDetails, {Key? key})
       : super(key: key);
 
   @override
@@ -21,7 +23,7 @@ class ChatSettingsPopupMenu extends StatefulWidget {
 }
 
 class _ChatSettingsPopupMenuState extends State<ChatSettingsPopupMenu> {
-  StreamSubscription notificationChangeSub;
+  StreamSubscription? notificationChangeSub;
 
   @override
   void dispose() {
@@ -37,7 +39,7 @@ class _ChatSettingsPopupMenuState extends State<ChatSettingsPopupMenu> {
         .stream
         .where((u) => u.type == 'm.push_rules')
         .listen(
-          (u) => setState(() => null),
+          (u) => setState(() {}),
         );
     final items = <PopupMenuEntry<String>>[
       widget.room.pushRuleState == PushRuleState.notify
@@ -47,7 +49,7 @@ class _ChatSettingsPopupMenuState extends State<ChatSettingsPopupMenu> {
                 children: [
                   const Icon(Icons.notifications_off_outlined),
                   const SizedBox(width: 12),
-                  Text(L10n.of(context).muteChat),
+                  Text(L10n.of(context)!.muteChat),
                 ],
               ),
             )
@@ -57,7 +59,7 @@ class _ChatSettingsPopupMenuState extends State<ChatSettingsPopupMenu> {
                 children: [
                   const Icon(Icons.notifications_on_outlined),
                   const SizedBox(width: 12),
-                  Text(L10n.of(context).unmuteChat),
+                  Text(L10n.of(context)!.unmuteChat),
                 ],
               ),
             ),
@@ -67,7 +69,7 @@ class _ChatSettingsPopupMenuState extends State<ChatSettingsPopupMenu> {
           children: [
             const Icon(Icons.delete_outlined),
             const SizedBox(width: 12),
-            Text(L10n.of(context).leave),
+            Text(L10n.of(context)!.leave),
           ],
         ),
       ),
@@ -81,7 +83,7 @@ class _ChatSettingsPopupMenuState extends State<ChatSettingsPopupMenu> {
             children: [
               const Icon(Icons.info_outline_rounded),
               const SizedBox(width: 12),
-              Text(L10n.of(context).chatDetails),
+              Text(L10n.of(context)!.chatDetails),
             ],
           ),
         ),
@@ -94,9 +96,9 @@ class _ChatSettingsPopupMenuState extends State<ChatSettingsPopupMenu> {
             final confirmed = await showOkCancelAlertDialog(
               useRootNavigator: false,
               context: context,
-              title: L10n.of(context).areYouSure,
+              title: L10n.of(context)!.areYouSure,
-              okLabel: L10n.of(context).ok,
+              okLabel: L10n.of(context)!.ok,
-              cancelLabel: L10n.of(context).cancel,
+              cancelLabel: L10n.of(context)!.cancel,
             );
             if (confirmed == OkCancelResult.ok) {
               final success = await showFutureLoadingDialog(

lib/widgets/connection_status_header.dart

@@ -1,3 +1,5 @@
+//@dart=2.12
+
 import 'dart:async';
 
 import 'package:flutter/material.dart';
@@ -9,15 +11,15 @@ import '../utils/localized_exception_extension.dart';
 import 'matrix.dart';
 
 class ConnectionStatusHeader extends StatefulWidget {
-  const ConnectionStatusHeader({Key key}) : super(key: key);
+  const ConnectionStatusHeader({Key? key}) : super(key: key);
 
   @override
   _ConnectionStatusHeaderState createState() => _ConnectionStatusHeaderState();
 }
 
 class _ConnectionStatusHeaderState extends State<ConnectionStatusHeader> {
-  StreamSubscription _onSyncSub;
+  StreamSubscription? _onSyncSub;
-  StreamSubscription _onSyncErrorSub;
+  StreamSubscription? _onSyncErrorSub;
   bool get _connected =>
       DateTime.now().millisecondsSinceEpoch -
           _lastSyncReceived.millisecondsSinceEpoch <
@@ -82,14 +84,15 @@ extension on SyncStatusUpdate {
   String toLocalizedString(BuildContext context) {
     switch (status) {
       case SyncStatus.waitingForResponse:
-        return L10n.of(context).loadingPleaseWait;
+        return L10n.of(context)!.loadingPleaseWait;
       case SyncStatus.error:
-        return (error.exception as Object).toLocalizedString(context);
+        return ((error?.exception ?? Object()) as Object)
+            .toLocalizedString(context);
       case SyncStatus.processing:
       case SyncStatus.cleaningUp:
       case SyncStatus.finished:
       default:
-        return L10n.of(context).synchronizingPleaseWait;
+        return L10n.of(context)!.synchronizingPleaseWait;
     }
   }
 }

lib/widgets/contacts_list.dart

@@ -1,3 +1,5 @@
+//@dart=2.12
+
 import 'dart:async';
 
 import 'package:flutter/material.dart';
@@ -14,15 +16,15 @@ class ContactsList extends StatefulWidget {
   final TextEditingController searchController;
 
   const ContactsList({
-    Key key,
+    Key? key,
-    @required this.searchController,
+    required this.searchController,
   }) : super(key: key);
   @override
   _ContactsState createState() => _ContactsState();
 }
 
 class _ContactsState extends State<ContactsList> {
-  StreamSubscription _onSync;
+  StreamSubscription? _onSync;
 
   @override
   void dispose() {
@@ -31,11 +33,11 @@ class _ContactsState extends State<ContactsList> {
   }
 
   DateTime _lastSetState = DateTime.now();
-  Timer _coolDown;
+  Timer? _coolDown;
 
   void _updateView() {
     _lastSetState = DateTime.now();
-    setState(() => null);
+    setState(() {});
   }
 
   @override
@@ -68,15 +70,16 @@ class _ContactsState extends State<ContactsList> {
 class _ContactListTile extends StatelessWidget {
   final Presence contact;
 
-  const _ContactListTile({Key key, @required this.contact}) : super(key: key);
+  const _ContactListTile({Key? key, required this.contact}) : super(key: key);
   @override
   Widget build(BuildContext context) {
     return FutureBuilder<Profile>(
         future:
             Matrix.of(context).client.getProfileFromUserId(contact.senderId),
         builder: (context, snapshot) {
-          final displayname =
+          final displayname = snapshot.data?.displayName ??
-              snapshot.data?.displayName ?? contact.senderId.localpart;
+              contact.senderId.localpart ??
+              'No valid MXID';
           final avatarUrl = snapshot.data?.avatarUrl;
           return ListTile(
             leading: SizedBox(
@@ -108,7 +111,7 @@ class _ContactListTile extends StatelessWidget {
               'rooms',
               Matrix.of(context)
                   .client
-                  .getDirectChatFromUserId(contact.senderId)
+                  .getDirectChatFromUserId(contact.senderId)!
             ]),
           );
         });

lib/widgets/layouts/two_column_layout.dart

@@ -1,4 +1,5 @@
 //@dart=2.12
+
 import 'package:flutter/material.dart';
 
 import 'package:fluffychat/config/themes.dart';