Can collpase conversation window

lib/ui/widgets/tablet_mode/conversations/conversation_window.dart

@@ -31,11 +31,16 @@ class _ConversationWindowState extends SafeState<ConversationWindow> {
   Conversation _conversation;
   String _convTitle;
   bool _error = false;
+  bool _collapsed = false;
 
   int get _convID => widget.convID;
 
+  final _convKey = UniqueKey();
+
   void _setError(bool e) => setState(() => _error = e);
 
+  void _toggleVisibility() => setState(() => _collapsed = !_collapsed);
+
   Future<void> _refresh() async {
     try {
       _setError(false);
@@ -71,6 +76,8 @@ class _ConversationWindowState extends SafeState<ConversationWindow> {
       return ConversationWindowContainer(
         title: Text(tr("Error")),
         onClose: widget.onClose,
+        onToggleCollpase: _toggleVisibility,
+        isCollapsed: _collapsed,
         body: buildErrorCard(tr("Could not load conversation information!"),
             actions: [
               FlatButton(
@@ -86,13 +93,18 @@ class _ConversationWindowState extends SafeState<ConversationWindow> {
       return ConversationWindowContainer(
         title: Text(tr("Loading...")),
         onClose: widget.onClose,
+        onToggleCollpase: _toggleVisibility,
+        isCollapsed: _collapsed,
         body: buildCenteredProgressBar(),
       );
 
     return ConversationWindowContainer(
       title: Text(_convTitle),
       onClose: widget.onClose,
+      onToggleCollpase: _toggleVisibility,
+      isCollapsed: _collapsed,
       body: ConversationScreen(
+        key: _convKey,
         conversationID: _convID,
       ),
     );

lib/ui/widgets/tablet_mode/conversations/conversation_window_container.dart

@@ -9,6 +9,8 @@ import 'package:flutter/material.dart';
 class ConversationWindowContainer extends StatelessWidget {
   final Widget title;
   final void Function() onClose;
+  final void Function() onToggleCollpase;
+  final bool isCollapsed;
   final Widget body;
 
   const ConversationWindowContainer({
@@ -16,9 +18,13 @@ class ConversationWindowContainer extends StatelessWidget {
     @required this.title,
     @required this.onClose,
     @required this.body,
+    @required this.onToggleCollpase,
+    @required this.isCollapsed,
   })  : assert(title != null),
         assert(onClose != null),
         assert(body != null),
+        assert(onToggleCollpase != null),
+        assert(isCollapsed != null),
         super(key: key);
 
   @override
@@ -26,15 +32,19 @@ class ConversationWindowContainer extends StatelessWidget {
     return Card(
       child: Container(
         width: 300,
-        height: 400,
+        height: !isCollapsed ? 400 : 40,
         child: Scaffold(
           appBar: AppBar(
-            title: title,
+            title: GestureDetector(child: title, onTap: onToggleCollpase),
             actions: <Widget>[
               IconButton(icon: Icon(Icons.close), onPressed: onClose),
             ],
           ),
-          body: body,
+          body: Visibility(
+            child: body,
+            visible: !isCollapsed,
+            maintainState: true,
+          ),
         ),
       ),
     );