Can delete all the notifications

lib/helpers/notifications_helper.dart

@@ -102,4 +102,10 @@ class NotificationsHelper {
         },
       ).exec())
           .isOK;
+
+  /// Delete all unread notifications
+  Future<bool> deleteAllNotifications() async =>
+      (await APIRequest(uri: "notifications/delete_all", needLogin: true)
+              .exec())
+          .isOK;
 }

lib/ui/screens/notifications_screen.dart

@@ -32,6 +32,8 @@ class _NotificationsScreenState extends State<NotificationsScreen> {
   GroupsList _groups;
   _Status _status = _Status.LOADING;
 
+  final _refreshKey = GlobalKey<RefreshIndicatorState>();
+
   void setStatus(_Status s) => setState(() => _status = s);
 
   Future<void> _loadList() async {
@@ -77,7 +79,22 @@ class _NotificationsScreenState extends State<NotificationsScreen> {
     return Column(
       children: [
         Expanded(
-          child: RefreshIndicator(child: _buildBody(), onRefresh: _loadList),
+          child: Stack(children: [
+            RefreshIndicator(
+              key: _refreshKey,
+              child: _buildBody(),
+              onRefresh: _loadList,
+            ),
+            // Add conversation button
+            Positioned(
+              right: 20.0,
+              bottom: 20.0,
+              child: FloatingActionButton(
+                onPressed: () => _deleteAllNotifications(),
+                child: Icon(Icons.delete),
+              ),
+            ),
+          ]),
         )
       ],
     );
@@ -134,6 +151,21 @@ class _NotificationsScreenState extends State<NotificationsScreen> {
 
     NotificationsHelper().markSeen(notif);
   }
+
+  /// Delete all the notifications
+  void _deleteAllNotifications() async {
+    if (!await showConfirmDialog(
+        context: context,
+        message: tr("Do you really want to delete all your notifications?")))
+      return;
+
+    if (!await NotificationsHelper().deleteAllNotifications()) {
+      showSimpleSnack(context, tr("Could not delete all your notifications!"));
+      return;
+    }
+
+    _refreshKey.currentState.show();
+  }
 }
 
 class _NotificationTile extends StatelessWidget {