mobile: Update to new client API

The settings screen was refactored too.

mobile/lib/screens/server_settings.dart

@@ -0,0 +1,110 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+
+import '../backend.dart';
+import '../settings.dart';
+
+class ServerSettingsScreen extends StatefulWidget {
+  @override
+  _ServerSettingsScreenState createState() => _ServerSettingsScreenState();
+}
+
+class _ServerSettingsScreenState extends State<ServerSettingsScreen> {
+  final hostController = TextEditingController();
+  final portController = TextEditingController();
+  final basePathController = TextEditingController();
+
+  BackendState backend;
+  StreamSubscription<ServerSettings> serverSubscription;
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+
+    backend = Backend.of(context);
+
+    if (serverSubscription != null) {
+      serverSubscription.cancel();
+    }
+
+    _settingsChanged(backend.settings.server.value);
+    serverSubscription = backend.settings.server.listen((settings) {
+      _settingsChanged(settings);
+    });
+  }
+
+  void _settingsChanged(ServerSettings settings) {
+    hostController.text = settings.host;
+    portController.text = settings.port.toString();
+    basePathController.text = settings.basePath;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: Text('Server settings'),
+        actions: <Widget>[
+          IconButton(
+            icon: const Icon(Icons.restore),
+            tooltip: 'Reset to default',
+            onPressed: () {
+              backend.settings.resetServerSettings();
+            },
+          ),
+          FlatButton(
+            onPressed: () async {
+              await backend.settings.setServerSettings(ServerSettings(
+                host: hostController.text,
+                port: int.parse(portController.text),
+                basePath: basePathController.text,
+              ));
+
+              Navigator.pop(context);
+            },
+            child: Text('DONE'),
+          ),
+        ],
+      ),
+      body: ListView(
+        children: <Widget>[
+          Padding(
+            padding: const EdgeInsets.all(16.0),
+            child: TextField(
+              controller: hostController,
+              decoration: InputDecoration(
+                labelText: 'Host',
+              ),
+            ),
+          ),
+          Padding(
+            padding: const EdgeInsets.all(16.0),
+            child: TextField(
+              controller: portController,
+              keyboardType: TextInputType.number,
+              decoration: InputDecoration(
+                labelText: 'Port',
+              ),
+            ),
+          ),
+          Padding(
+            padding: const EdgeInsets.all(16.0),
+            child: TextField(
+              controller: basePathController,
+              decoration: InputDecoration(
+                labelText: 'API path',
+              ),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+
+  @override
+  void dispose() {
+    super.dispose();
+    serverSubscription.cancel();
+  }
+}