Implement server selection

This lets the user select the fully qualified domain name (FQDN) of the
MQTT broker.

The FQDN is not yet preserved after a manual disconnect.

2 files changed, 22 insertions, 14 deletions

diff --git a/lib/data.dart b/lib/data.dart
index eaf301a..365f5bc 100644
--- a/lib/data.dart
+++ b/lib/data.dart
@@ -2,7 +2,6 @@ import 'package:flutter/foundation.dart';
 import 'package:mqtt_client/mqtt_client.dart';
 import 'package:mqtt_client/mqtt_server_client.dart';
 
-const String brokerHostname = 'sia.xengineering.eu';
 const int brokerPort = 1883;
 const String topicPrefix = 'sia';
 
@@ -47,6 +46,8 @@ class AppState with ChangeNotifier {
   Map<String, bool> contacts = <String, bool>{};
   late MqttServerClient _client;
 
+  String fqdn = '';
+
   AppState();
 
   void process(MachineEvent event) {
@@ -86,7 +87,7 @@ class AppState with ChangeNotifier {
 
   void _initMqtt() {
     _client = MqttServerClient(
-      brokerHostname,
+      fqdn,
       'sia_app_${DateTime.now().millisecondsSinceEpoch}',
     );
 
diff --git a/lib/ui.dart b/lib/ui.dart
index 7a97f32..a191f5f 100644
--- a/lib/ui.dart
+++ b/lib/ui.dart
@@ -29,19 +29,26 @@ class ConnectionPage extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return Scaffold(
-      appBar: AppBar(title: const Text("Connection")),
-      body: const Padding(
-        padding: EdgeInsets.all(16.0),
-        child: TextField(
-          decoration: InputDecoration(
-            labelText: "Server name",
-            hintText: "iot.example.org",
-            border: OutlineInputBorder(),
+    return Consumer<AppState>(
+      builder: (_, AppState state, _) {
+        return Scaffold(
+          appBar: AppBar(title: const Text("Connection")),
+          body: Padding(
+            padding: const EdgeInsets.all(16.0),
+            child: TextField(
+              decoration: const InputDecoration(
+                labelText: "Server name",
+                hintText: "iot.example.org",
+                border: OutlineInputBorder(),
+              ),
+              onChanged: (String value) {
+                state.fqdn = value;
+              },
+            ),
           ),
-        ),
-      ),
-      bottomNavigationBar: const ConnectionStatus(),
+          bottomNavigationBar: const ConnectionStatus(),
+        );
+      }
     );
   }
 }