working save and load functionality with custom datastructures

frontend/lib/modules/greeter.dart

@@ -1,44 +1,73 @@
+import 'package:fast_network_navigation/structs/trip.dart';
+
 import 'package:flutter/material.dart';
 
-Widget Greeter(ThemeData theme, {bool full = false}) {
-  String greeterText = "";
-  try {
-    String cityName = getCityName();
-    greeterText = "Welcome to $cityName!";
-  } catch (e) {
-    greeterText = "Welcome ...";
-  }
+class Greeter extends StatefulWidget {
+  final Future<Trip> trip;
+  final bool standalone;
 
-  Widget topGreeter = Text(
-    greeterText,
-    style: TextStyle(color: theme.primaryColor, fontSize: 24.0, fontWeight: FontWeight.bold),
-    maxLines: 1,
-  );
+  Greeter({
+    required this.standalone,
+    required this.trip
+  });
 
-  Widget bottomGreeter = Container();
-  if (full) {
-    bottomGreeter = Text(
-      "Busy day ahead? Here is how to make the most of it!",
-      style: TextStyle(color: Colors.black, fontSize: 18),
-      textAlign: TextAlign.center,
-      );
-  }
-  Widget greeter = Center(
-    child: Column(
-      children: [
-        if (!full) Padding(padding: EdgeInsets.only(top: 24.0)),
-        topGreeter,
-        if (full) bottomGreeter,
-        Padding(padding: EdgeInsets.only(bottom: 24.0)),
-      ],
-    ),
-  );
-
-  return greeter;
+  @override
+  State<Greeter> createState() => _GreeterState();
 }
 
 
 
-String getCityName() {
-  return "Paris";
+class _GreeterState extends State<Greeter> {
+  Widget greeterBuild (BuildContext context, AsyncSnapshot<Trip> snapshot) {
+    ThemeData theme = Theme.of(context);
+    String cityName = "";
+    if (snapshot.hasData) {
+      cityName = snapshot.data?.cityName ?? '...';
+    } else if (snapshot.hasError) {
+      cityName = "error";
+    } else { // still awaiting the cityname
+      cityName = "...";
+    }
+
+    Widget topGreeter = Text(
+      'Welcome to $cityName!',
+      style: TextStyle(color: theme.primaryColor, fontWeight: FontWeight.bold, fontSize: 24),
+    );
+
+    if (widget.standalone) {
+      return Center(
+        child: Padding(
+          padding: EdgeInsets.only(top: 24.0),
+          child: topGreeter,
+        ),
+      );
+    } else {
+      return Center(
+        child: Column(
+          children: [
+            Padding(padding: EdgeInsets.only(top: 24.0)),
+            topGreeter,
+            bottomGreeter,
+            Padding(padding: EdgeInsets.only(bottom: 24.0)),
+          ],
+        )
+      );
+    }
+  }
+
+  Widget bottomGreeter = const Text(
+    "Busy day ahead? Here is how to make the most of it!",
+    style: TextStyle(color: Colors.black, fontSize: 18),
+    textAlign: TextAlign.center,
+  );
+
+
+
+  @override
+  Widget build(BuildContext context) {
+    return FutureBuilder(
+      future: widget.trip,
+      builder: greeterBuild,
+    );
+  }
 }

frontend/lib/modules/landmark_card.dart

@@ -32,7 +32,7 @@ class _LandmarkCardState extends State<LandmarkCard> {
               // force a fixed width
               width: 160,
               child: Image.network(
-                widget.landmark.imageURL!,
+                widget.landmark.imageURL ?? '',
                 errorBuilder: (context, error, stackTrace) => Icon(Icons.question_mark_outlined),
                 // TODO: make this a switch statement to load a placeholder if null
                 // cover the whole container meaning the image will be cropped

frontend/lib/modules/landmarks_overview.dart

@@ -5,6 +5,7 @@ import 'package:fast_network_navigation/structs/landmark.dart';
 
 import 'package:fast_network_navigation/structs/trip.dart';
 import 'package:flutter/material.dart';
+import 'package:shared_preferences/shared_preferences.dart';
 
 
 
@@ -31,7 +32,7 @@ class _LandmarksOverviewState extends State<LandmarksOverview> {
         builder: (BuildContext context, AsyncSnapshot<LinkedList<Landmark>> snapshot) {
           List<Widget> children;
           if (snapshot.hasData) {
-            children = [landmarksWithSteps(snapshot.data!)];
+            children = [landmarksWithSteps(snapshot.data!), saveButton()];
           } else if (snapshot.hasError) {
             children = <Widget>[
               const Icon(
@@ -41,7 +42,7 @@ class _LandmarksOverviewState extends State<LandmarksOverview> {
               ),
               Padding(
                 padding: const EdgeInsets.only(top: 16),
-                child: Text('Error: ${snapshot.error}'),
+                child: Text('Error: ${snapshot.error}', style: TextStyle(fontSize: 12)),
               ),
             ];
           } else {
@@ -57,6 +58,15 @@ class _LandmarksOverviewState extends State<LandmarksOverview> {
       ),
     );
   }
+  Widget saveButton() => ElevatedButton(
+    onPressed: () async {
+      Trip? trip = await widget.trip;
+      SharedPreferences prefs = await SharedPreferences.getInstance();
+      trip?.toPrefs(prefs);
+    },
+    child: const Text('Save'),
+  );
+
 }
 
 Widget landmarksWithSteps(LinkedList<Landmark> landmarks) {
@@ -117,3 +127,4 @@ Future<LinkedList<Landmark>> getLandmarks (Future<Trip>? trip) async {
   Trip tripf = await trip!;
   return tripf.landmarks;
 }
+

frontend/lib/modules/map.dart

@@ -27,12 +27,18 @@ class _MapWidgetState extends State<MapWidget> {
   Set<Marker> markers = <Marker>{};
   
 
-  void _onMapCreated(GoogleMapController controller) {
+  void _onMapCreated(GoogleMapController controller) async {
     mapController = controller;
+    Trip? trip = await widget.trip;
+    List<double>? newLocation = trip?.landmarks.first.location;
+    if (newLocation != null) {
+      CameraUpdate update = CameraUpdate.newLatLng(LatLng(newLocation[0], newLocation[1]));
+      controller.moveCamera(update);
+    }
     drawLandmarks();
   }
 
-  
+
   void _onCameraIdle() {
     // print(mapController.getLatLng(ScreenCoordinate(x: 0, y: 0)));
   }
@@ -41,16 +47,18 @@ class _MapWidgetState extends State<MapWidget> {
   void drawLandmarks() async {
     // (re)draws landmarks on the map
     Trip? trip = await widget.trip;
-    LinkedList<Landmark> landmarks = trip!.landmarks;
-    setState(() {
-      for (Landmark landmark in landmarks) {
-        markers.add(Marker(
-          markerId: MarkerId(landmark.name),
-          position: LatLng(landmark.location[0], landmark.location[1]),
-          infoWindow: InfoWindow(title: landmark.name, snippet: landmark.type.name),
-        ));
-      }
-    });
+    LinkedList<Landmark>? landmarks = trip?.landmarks;
+    if (landmarks != null){
+      setState(() {
+        for (Landmark landmark in landmarks) {
+          markers.add(Marker(
+            markerId: MarkerId(landmark.name),
+            position: LatLng(landmark.location[0], landmark.location[1]),
+            infoWindow: InfoWindow(title: landmark.name, snippet: landmark.type.name),
+          ));
+        }
+      });
+    }
   }
 
 

frontend/lib/modules/trips_overview.dart

@@ -30,7 +30,7 @@ class _TripsOverviewState extends State<TripsOverview> {
           onTap: () {
             Navigator.of(context).push(
               MaterialPageRoute(
-                builder: (context) => BasePage(mainScreen: "map", trip: trip)
+                builder: (context) => BasePage(mainScreen: "map", trip: Future.value(trip))
               )
             );
           },