Intro/Settings screen

Author: code418

lib/app_preferences.dart

@@ -0,0 +1,37 @@
+import 'package:shared_preferences/shared_preferences.dart';
+
+const String _keyDistanceUnit = 'distance_unit';
+
+enum DistanceUnit { meters, miles }
+
+extension DistanceUnitX on DistanceUnit {
+  String get label => this == DistanceUnit.meters ? 'Meters' : 'Miles';
+  String get short => this == DistanceUnit.meters ? 'm' : 'mi';
+}
+
+/// User preferences (distance display, etc.).
+class AppPreferences {
+  static Future<DistanceUnit> getDistanceUnit() async {
+    final prefs = await SharedPreferences.getInstance();
+    final v = prefs.getString(_keyDistanceUnit);
+    if (v == 'miles') return DistanceUnit.miles;
+    return DistanceUnit.meters;
+  }
+
+  static Future<void> setDistanceUnit(DistanceUnit unit) async {
+    final prefs = await SharedPreferences.getInstance();
+    await prefs.setString(_keyDistanceUnit, unit == DistanceUnit.miles ? 'miles' : 'meters');
+  }
+
+  /// Converts meters to display value; callers use [AppPreferences.getDistanceUnit] for unit.
+  static double metersToDisplay(double meters, DistanceUnit unit) {
+    if (unit == DistanceUnit.miles) return meters * 0.000621371;
+    return meters;
+  }
+
+  static String formatDistance(double meters, DistanceUnit unit) {
+    final v = metersToDisplay(meters, unit);
+    if (unit == DistanceUnit.miles) return '${v.toStringAsFixed(1)} mi';
+    return '${v.toStringAsFixed(0)} m';
+  }
+}

lib/home.dart

@@ -52,6 +52,13 @@ class HomeMenu extends StatelessWidget {
             Navigator.pushNamed(context, '/leaderboard');
           },
         ),
+        HomeMenuButton(
+          text: 'Settings',
+          icon: Icon(Icons.settings),
+          onPressed: () {
+            Navigator.pushNamed(context, '/settings');
+          },
+        ),
         /*HomeMenuButton(
           text: 'Upload Photo',
           onPressed: () {