Reenable rotation to and from landscape mode on Android

frontend/android/app/src/main/AndroidManifest.xml

@@ -12,7 +12,6 @@
         <activity
             android:name=".MainActivity"
             android:launchMode="singleTop"
-            android:screenOrientation="portrait"
             android:theme="@style/LaunchTheme"
             android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
             android:hardwareAccelerated="true"

frontend/lib/entry_widget.dart

@@ -10,6 +10,9 @@ import 'home/home_page.dart';
 import 'intro_slides/intro_screen.dart';
 import 'themes.dart';
 
+const introRouteName = "/intro";
+const homeRouteName = "/home";
+
 class EntryWidget extends StatelessWidget {
   const EntryWidget({Key? key}) : super(key: key);
 
@@ -26,24 +29,22 @@ class EntryWidget extends StatelessWidget {
         if (snapshot.hasError && error != null) {
           return ErrorMessage(error.toString());
         } else if (snapshot.hasData && settings != null) {
-          final routes = <String, WidgetBuilder>{};
-          String? initialRoute;
+          final routes = <String, WidgetBuilder>{
+            introRouteName: (context) => IntroScreen(
+                  onFinishedCallback: () => settings.setFirstStart(enabled: false),
+                ),
+            homeRouteName: (context) => HomePage(
+                  showVerification: configuration.showVerification,
+                )
+          };
 
-          if (settings.firstStart) {
-            routes.addAll(<String, WidgetBuilder>{
-              '/intro': (context) => IntroScreen(
-                    onFinishedCallback: () => settings.setFirstStart(enabled: false),
-                  ),
-            });
-            initialRoute = '/intro';
-          }
+          final String initialRoute = settings.firstStart ? introRouteName : homeRouteName;
 
           return MaterialApp(
             title: 'Ehrenamtskarte',
             theme: lightTheme,
             darkTheme: darkTheme,
             themeMode: ThemeMode.system,
-            initialRoute: initialRoute,
             debugShowCheckedModeBanner: false,
             localizationsDelegates: const [
               GlobalMaterialLocalizations.delegate,
@@ -53,9 +54,7 @@ class EntryWidget extends StatelessWidget {
             ],
             supportedLocales: const [Locale('de')],
             locale: const Locale('de'),
-            home: HomePage(
-              showVerification: configuration.showVerification,
-            ),
+            initialRoute: initialRoute,
             routes: routes,
           );
         } else {

frontend/lib/intro_slides/intro_screen.dart

@@ -1,3 +1,4 @@
+import 'package:ehrenamtskarte/entry_widget.dart';
 import 'package:flutter/material.dart';
 import 'package:intro_slider/intro_slider.dart';
 import 'package:intro_slider/slide_object.dart';
@@ -82,7 +83,7 @@ class IntroScreenState extends State<IntroScreen> {
     if (onFinishedCallback != null) {
       onFinishedCallback();
     }
-    Navigator.of(context).pop();
+    Navigator.of(context).pushReplacementNamed(homeRouteName);
   }
 
   @override

frontend/lib/map/map/map.dart

@@ -1,12 +1,14 @@
 import 'dart:io';
 import 'dart:math' as math;
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:geolocator/geolocator.dart';
 import 'package:maplibre_gl/mapbox_gl.dart';
 
 import '../../configuration/configuration.dart';
 import 'attribution_dialog.dart';
 import 'map_controller.dart';
+import 'screen_parent_resizer.dart';
 
 typedef OnFeatureClickCallback = void Function(dynamic feature);
 typedef OnNoFeatureClickCallback = void Function();
@@ -43,8 +45,9 @@ class _MapState extends State<Map> implements MapController {
   MaplibreMapController? _controller;
   Symbol? _symbol;
   bool _permissionGiven = false;
-  Stack? _mapboxView;
+  Widget? _currentMapLibreView;
   bool _isAnimating = false;
+  bool _isMapInitialized = false;
 
   @override
   void didChangeDependencies() {
@@ -59,13 +62,16 @@ class _MapState extends State<Map> implements MapController {
     final pixelRatio = MediaQuery.of(context).devicePixelRatio;
     final compassMargin = Platform.isIOS ? statusBarHeight / pixelRatio : statusBarHeight * pixelRatio;
 
-    if (_mapboxView == null || !_isAnimating) {
+    final Widget? currentMapLibreView = _currentMapLibreView;
+    final Widget maplibreView;
+
+    if (currentMapLibreView == null || !_isAnimating) {
       final userLocation = widget.userLocation;
       final cameraPosition = userLocation != null
           ? CameraPosition(target: userLocation, zoom: Map.userLocationZoomLevel)
           : const CameraPosition(target: Map.centerOfBavaria, zoom: Map.bavariaZoomLevel);
 
-      _mapboxView = Stack(
+      maplibreView = Stack(
         children: [
           MaplibreMap(
             initialCameraPosition: cameraPosition,
@@ -106,15 +112,30 @@ class _MapState extends State<Map> implements MapController {
           ),
         ],
       );
+    } else {
+      maplibreView = currentMapLibreView;
     }
-    return _mapboxView ?? Container();
+
+    // Apply ScreenParentResizer only on android
+    // https://github.com/flutter-mapbox-gl/maps/issues/195
+    return defaultTargetPlatform == TargetPlatform.android
+        ? ScreenParentResizer(
+            childInitialized: _isMapInitialized,
+            child: maplibreView,
+          )
+        : maplibreView;
   }
 
   void _onMapCreated(MaplibreMapController controller) {
     _controller = controller;
     if (widget.locationAvailable) {
       _controller?.updateMyLocationTrackingMode(MyLocationTrackingMode.Tracking);
     }
+
+    setState(() {
+      _isMapInitialized = true;
+    });
+
     final onMapCreated = widget.onMapCreated;
     if (onMapCreated != null) {
       onMapCreated(this);

frontend/lib/map/map/screen_parent_resizer.dart

@@ -0,0 +1,98 @@
+import 'dart:math';
+import 'package:flutter/material.dart';
+
+/// A widget which resizes the child widget twice when the orientation changes.
+///
+/// * Firstly, the child put in a container with the following constraints:
+///   `width = height = max(parentMaxWidth, parentMaxHeight)`. This creates a square.
+/// * Secondly, the child is resized to
+///   `width = parentMaxWidth, height = parentMaxHeight. This sizes the child according to the parent constraints. This
+///   resize only happens if the child is already initialized. If it is not yet initialized then the resize is delayed.
+class ScreenParentResizer extends StatelessWidget {
+  final Widget child;
+  final bool childInitialized;
+
+  const ScreenParentResizer({
+    Key? key,
+    required this.child,
+    required this.childInitialized,
+  }) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return LayoutBuilder(
+      builder: (BuildContext context, BoxConstraints constraints) {
+        return _InnerScreenParentResizer(
+          childInitialized: childInitialized,
+          constraints: constraints,
+          child: child,
+        );
+      },
+    );
+  }
+}
+
+class _InnerScreenParentResizer extends StatefulWidget {
+  final Widget? child;
+  final bool childInitialized;
+  final BoxConstraints constraints;
+
+  const _InnerScreenParentResizer({
+    Key? key,
+    required Widget this.child,
+    required this.childInitialized,
+    required this.constraints,
+  }) : super(key: key);
+
+  @override
+  State createState() => _InnerScreenParentResizerState();
+}
+
+class _InnerScreenParentResizerState extends State<_InnerScreenParentResizer> {
+  Orientation? _lastBuildOrientation;
+  Orientation? _initialOrientationUpdate;
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+
+    // As soon as the child is initialized we trigger the orientation update
+    if (widget.childInitialized) {
+      setState(() {
+        _lastBuildOrientation = _initialOrientationUpdate;
+      });
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final maximum = max(
+      widget.constraints.maxWidth,
+      widget.constraints.maxHeight,
+    );
+
+    final currentOrientation = MediaQuery.of(context).orientation;
+    final isOverDrawingSquare = currentOrientation != _lastBuildOrientation;
+
+    if (isOverDrawingSquare) {
+      // We only trigger a resize if the child component finished initializing
+      if (widget.childInitialized) {
+        setState(() {
+          _lastBuildOrientation = currentOrientation;
+        });
+      } else {
+        _initialOrientationUpdate = currentOrientation;
+      }
+    }
+
+    final width = isOverDrawingSquare ? maximum : null;
+    final height = isOverDrawingSquare ? maximum : null;
+
+    return OverflowBox(
+      alignment: Alignment.topLeft,
+      maxHeight: height,
+      maxWidth: width,
+      child: widget.child,
+    );
+  }
+}