Add public room discovery

lib/components/list_items/public_room_list_item.dart

@@ -0,0 +1,48 @@
+import 'package:famedlysdk/famedlysdk.dart';
+import 'package:flutter/material.dart';
+
+import '../../i18n/i18n.dart';
+import '../../utils/app_route.dart';
+import '../../views/chat.dart';
+import '../avatar.dart';
+import '../matrix.dart';
+
+class PublicRoomListItem extends StatelessWidget {
+  final PublicRoomEntry publicRoomEntry;
+
+  const PublicRoomListItem(this.publicRoomEntry, {Key key}) : super(key: key);
+
+  void joinAction(BuildContext context) async {
+    final success = await Matrix.of(context)
+        .tryRequestWithLoadingDialog(publicRoomEntry.join());
+    if (success != false) {
+      await Navigator.of(context).push(
+        AppRoute.defaultRoute(
+          context,
+          ChatView(publicRoomEntry.roomId),
+        ),
+      );
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final bool hasTopic =
+        publicRoomEntry.topic != null && publicRoomEntry.topic.isNotEmpty;
+    return ListTile(
+      leading:
+          Avatar(MxContent(publicRoomEntry.avatarUrl), publicRoomEntry.name),
+      title: Text(hasTopic
+          ? "${publicRoomEntry.name} (${publicRoomEntry.numJoinedMembers})"
+          : publicRoomEntry.name),
+      subtitle: Text(
+        hasTopic
+            ? publicRoomEntry.topic
+            : I18n.of(context).countParticipants(
+                publicRoomEntry.numJoinedMembers?.toString() ?? "0"),
+        maxLines: 1,
+      ),
+      onTap: () => joinAction(context),
+    );
+  }
+}