bin/userpicker_base_shell/lib/user_picker_base_shell_screen.dart

// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'package:fidl_fuchsia_sys/fidl_async.dart';
import 'package:flutter/material.dart';
import 'package:fuchsia_scenic_flutter/child_view.dart' show ChildView;
import 'package:meta/meta.dart';

import 'clock.dart';
import 'user_picker_base_shell_model.dart';
import 'user_picker_screen.dart';

/// The root widget which displays all the other windows of this app.
class UserPickerBaseShellScreen extends StatelessWidget {
  /// Launcher to launch the kernel panic module if needed.
  final Launcher launcher;

  /// Constructor.
  const UserPickerBaseShellScreen({
    @required this.launcher,
    Key key,
  }) : super(key: key);
  @override
  Widget build(BuildContext context) {
    return new ScopedModelDescendant<UserPickerBaseShellModel>(
      builder: (
        BuildContext context,
        Widget child,
        UserPickerBaseShellModel model,
      ) {
        List<Widget> stackChildren = <Widget>[];

        if (model.childViewConnection == null || model.loadingChildView) {
          stackChildren.addAll(<Widget>[
            new UserPickerScreen(),
            new Align(
              alignment: FractionalOffset.center,
              child: new Offstage(
                offstage: !model.showingClock,
                child: new Clock(),
              ),
            ),
          ]);
        }

        if (model.childViewConnection != null) {
          stackChildren.add(new Offstage(
            child: new Container(
              color: Colors.black,
              child: new ChildView(connection: model.childViewConnection),
            ),
            offstage: model.loadingChildView,
          ));
        }

        return new Stack(fit: StackFit.expand, children: stackChildren);
      },
    );
  }
}