feat: add selection property to user list item

lib/src/user_item.dart

@@ -17,13 +17,14 @@ import 'stream_chat_theme.dart';
 /// Modify it to change the widget appearance.
 class UserItem extends StatelessWidget {
   /// Instantiate a new UserItem
-  const UserItem(
+  const UserItem({
-      {Key key,
+    Key key,
-      @required this.user,
+    @required this.user,
-      this.onTap,
+    this.onTap,
-      this.onLongPress,
+    this.onLongPress,
-      this.onImageTap})
+    this.onImageTap,
-      : super(key: key);
+    this.selected = false,
+  }) : super(key: key);
 
   /// Function called when tapping this widget
   final void Function(User) onTap;
@@ -37,6 +38,9 @@ class UserItem extends StatelessWidget {
   /// The function called when the image is tapped
   final void Function(User) onImageTap;
 
+  /// If true the [UserItem] will show a trailing checkmark
+  final bool selected;
+
   @override
   Widget build(BuildContext context) {
     return ListTile(
@@ -58,6 +62,15 @@ class UserItem extends StatelessWidget {
               onImageTap(user);
             }
           }),
+      trailing: selected
+          ? CircleAvatar(
+              child: Icon(
+                StreamIcons.check,
+                size: 20,
+              ),
+              radius: 10,
+            )
+          : null,
       title: Text(user.name),
       subtitle: _buildLastActive(context),
     );

lib/src/user_list_view.dart

@@ -60,6 +60,7 @@ class UserListView extends StatefulWidget {
     this.userItemBuilder,
     this.separatorBuilder,
     this.onImageTap,
+    this.selectedUsers,
     this.swipeToAction = false,
     this.pullToRefresh = true,
   }) : super(key: key);
@@ -119,6 +120,9 @@ class UserListView extends StatefulWidget {
   /// Set it to false to disable the pull-to-refresh widget
   final bool pullToRefresh;
 
+  /// Sets a blue trailing checkMark in [UserItem] for all the [selectedUsers]
+  final List<User> selectedUsers;
+
   @override
   _UserListViewState createState() => _UserListViewState();
 }
@@ -309,6 +313,7 @@ class _UserListViewState extends State<UserListView>
     final usersProvider = UsersBloc.of(context);
     if (i < users.length) {
       final user = users[i];
+      final selected = widget.selectedUsers?.contains(user) ?? false;
 
       UserTapCallback onTap;
       if (widget.onUserTap != null) {
@@ -335,6 +340,7 @@ class _UserListViewState extends State<UserListView>
         onTap: (user) => onTap(user, widget.userWidget),
         onLongPress: widget.onUserLongPress,
         onImageTap: widget.onImageTap,
+        selected: selected,
       );
     } else {
       return _buildQueryProgressIndicator(context, usersProvider);