better visual coherence

frontend/lib/pages/current_trip.dart

@@ -1,11 +1,10 @@
-import 'package:anyway/modules/current_trip_save_button.dart';
+import 'package:anyway/constants.dart';
 import 'package:flutter/material.dart';
 import 'package:sliding_up_panel/sliding_up_panel.dart';
 
 import 'package:anyway/structs/trip.dart';
-import 'package:anyway/modules/current_trip_landmarks_list.dart';
-import 'package:anyway/modules/current_trip_greeter.dart';
 import 'package:anyway/modules/current_trip_map.dart';
+import 'package:anyway/modules/current_trip_panel.dart';
 
 
 
@@ -27,15 +26,20 @@ class _TripPageState extends State<TripPage> {
   @override
   Widget build(BuildContext context) {
     return SlidingUpPanel(
-        panelBuilder: (sc) => _panelFull(sc),
-        // collapsed: _floatingCollapsed(),
+        // use panelBuilder instead of panel so that we can reuse the scrollcontroller for the listview
+        panelBuilder: (scrollcontroller) => CurrentTripPanel(controller: scrollcontroller, trip: widget.trip),
+        // using collapsed and panelBuilder seems to show both at the same time, so we include the greeter in the panelBuilder
+        // collapsed: Greeter(trip: widget.trip),
         body: CurrentTripMap(trip: widget.trip),
-        // renderPanelSheet: false,
-        // backdropEnabled: true,
-        maxHeight: MediaQuery.of(context).size.height * 0.8,
-        padding: EdgeInsets.only(left: 10, right: 10, top: 25, bottom: 10),
-        // panelSnapping: false,
-        borderRadius: BorderRadius.only(topLeft: Radius.circular(25), topRight: Radius.circular(25)),
+        minHeight: MediaQuery.of(context).size.height * TRIP_PANEL_MIN_HEIGHT,
+        maxHeight: MediaQuery.of(context).size.height * TRIP_PANEL_MAX_HEIGHT,
+        // padding in this context is annoying: it offsets the notion of vertical alignment.
+        // children that want to be centered vertically need to have their size adjusted by 2x the padding
+        padding: const EdgeInsets.only(top: 10),
+        // Panel snapping should not be disabled because it significantly improves the user experience
+        // panelSnapping: false
+        borderRadius: const BorderRadius.only(topLeft: Radius.circular(25), topRight: Radius.circular(25)),
+        parallaxEnabled: true,
         boxShadow: const [
           BoxShadow(
             blurRadius: 20.0,
@@ -44,41 +48,4 @@ class _TripPageState extends State<TripPage> {
         ],
     );
   }
-
-  
-  Widget _panelFull(ScrollController sc) {
-    return ListenableBuilder(
-      listenable: widget.trip,
-      builder: (context, child) {
-        if (widget.trip.uuid != 'pending' && widget.trip.uuid != 'error') {
-          return ListView(
-            controller: sc,
-            padding: EdgeInsets.only(bottom: 35),
-            children: [
-              Greeter(trip: widget.trip),
-              ...landmarksList(widget.trip),
-              Padding(padding: EdgeInsets.only(top: 10)),
-              Center(child: saveButton(widget.trip)),
-            ],
-          );
-        } else if(widget.trip.uuid == 'pending') {
-          return Greeter(trip: widget.trip);
-        } else {
-          return Column(
-            children: [
-              const Icon(
-                Icons.error_outline,
-                color: Colors.red,
-                size: 60,
-              ),
-              Padding(
-                padding: const EdgeInsets.only(top: 16),
-                child: Text('Error: ${widget.trip.errorDescription}'),
-              ),
-            ],
-          );
-        }
-      }
-    );
-  }
 }