Start to show call window

lib/ui/widgets/tablet_mode/calls/call_window_widget.dart

@@ -0,0 +1,32 @@
+import 'package:comunic/ui/screens/call_screen.dart';
+import 'package:flutter/material.dart';
+
+/// Call window widget
+///
+/// @author Pierre HUBERT
+
+class CallWindowWidget extends StatefulWidget {
+  final int convID;
+
+  const CallWindowWidget({
+    Key key,
+    this.convID,
+  })  : assert(convID != null),
+        super(key: key);
+
+  @override
+  _CallWindowWidgetState createState() => _CallWindowWidgetState();
+}
+
+class _CallWindowWidgetState extends State<CallWindowWidget> {
+  @override
+  Widget build(BuildContext context) {
+    return Positioned(
+      width: 500,
+      height: 200,
+      right: 10,
+      top: 10,
+      child: Card(child: CallScreen(convID: widget.convID)),
+    );
+  }
+}

lib/ui/widgets/tablet_mode/calls/calls_area.dart

@@ -1,5 +1,4 @@
-import 'package:comunic/utils/intl_utils.dart';
+import 'package:comunic/ui/widgets/tablet_mode/calls/call_window_widget.dart';
-import 'package:comunic/utils/ui_utils.dart';
 import 'package:flutter/material.dart';
 
 /// Tablets mode calls area
@@ -14,13 +13,25 @@ class CallsArea extends StatefulWidget {
 }
 
 class CallsAreaState extends State<CallsArea> {
+  final _openCalls = Map<int, Key>();
+
   @override
   Widget build(BuildContext context) {
-    return Stack();
+    return Stack(
+      children: _openCalls
+          .map((convID, key) =>
+              MapEntry(convID, CallWindowWidget(key: key, convID: convID)))
+          .values
+          .toList(),
+    );
   }
 
   /// Open a new call
   void openCall(int convID) {
-    showSimpleSnack(context, tr("Open call $convID"));
+    if (!_openCalls.containsKey(convID)) {
+      setState(() {
+        _openCalls[convID] = UniqueKey();
+      });
+    }
   }
 }