Add settings screen

lib/main_screen.dart

@@ -1,5 +1,7 @@
 import 'package:flutter/material.dart';
-import 'package:traccar_client/status_screen.dart';
+
+import 'status_screen.dart';
+import 'settings_screen.dart';
 
 class MainScreen extends StatelessWidget {
   const MainScreen({super.key});
@@ -111,7 +113,10 @@ class MainScreen extends StatelessWidget {
                     Align(
                       alignment: Alignment.centerRight,
                       child: OutlinedButton(
-                        onPressed: () {},
+                        onPressed: () => Navigator.push(
+                          context,
+                          MaterialPageRoute(builder: (_) => const SettingsScreen()),
+                        ),
                         child: const Text('Advanced settings'),
                       ),
                     ),

lib/settings_screen.dart

@@ -0,0 +1,103 @@
+import 'package:flutter/material.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+class SettingsScreen extends StatefulWidget {
+  const SettingsScreen({super.key});
+
+  @override
+  State<SettingsScreen> createState() => _SettingsScreenState();
+}
+
+class _SettingsScreenState extends State<SettingsScreen> {
+  late SharedPreferences prefs;
+
+  final deviceIdController = TextEditingController();
+  final serverUrlController = TextEditingController();
+  final accuracyController = TextEditingController();
+  final distanceController = TextEditingController();
+  final frequencyController = TextEditingController();
+  bool offlineBuffering = false;
+
+  @override
+  void initState() {
+    super.initState();
+    _loadSettings();
+  }
+
+  Future<void> _loadSettings() async {
+    prefs = await SharedPreferences.getInstance();
+
+    setState(() {
+      deviceIdController.text = prefs.getString('deviceId') ?? '';
+      serverUrlController.text = prefs.getString('serverUrl') ?? '';
+      accuracyController.text = prefs.getString('accuracy') ?? 'high';
+      distanceController.text = prefs.getString('distance') ?? '50';
+      frequencyController.text = prefs.getString('frequency') ?? '60';
+      offlineBuffering = prefs.getBool('offlineBuffering') ?? true;
+    });
+  }
+
+  Future<void> _saveSettings() async {
+    await prefs.setString('deviceId', deviceIdController.text);
+    await prefs.setString('serverUrl', serverUrlController.text);
+    await prefs.setString('accuracy', accuracyController.text);
+    await prefs.setString('distance', distanceController.text);
+    await prefs.setString('frequency', frequencyController.text);
+    await prefs.setBool('offlineBuffering', offlineBuffering);
+
+    if (mounted) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(content: Text('Settings saved')),
+      );
+    }
+  }
+
+  @override
+  void dispose() {
+    deviceIdController.dispose();
+    serverUrlController.dispose();
+    accuracyController.dispose();
+    distanceController.dispose();
+    frequencyController.dispose();
+    super.dispose();
+  }
+
+  Widget _buildTextField(String label, TextEditingController controller) {
+    return TextField(
+      controller: controller,
+      decoration: InputDecoration(labelText: label),
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('Settings'),
+        actions: [
+          IconButton(
+            icon: const Icon(Icons.save),
+            onPressed: _saveSettings,
+          ),
+        ],
+      ),
+      body: ListView(
+        padding: const EdgeInsets.all(16),
+        children: [
+          _buildTextField('Device ID', deviceIdController),
+          _buildTextField('Server URL', serverUrlController),
+          _buildTextField('Location Accuracy', accuracyController),
+          _buildTextField('Distance (meters)', distanceController),
+          _buildTextField('Frequency (seconds)', frequencyController),
+          SwitchListTile(
+            title: const Text('Offline Buffering'),
+            value: offlineBuffering,
+            onChanged: (value) {
+              setState(() => offlineBuffering = value);
+            },
+          ),
+        ],
+      ),
+    );
+  }
+}