material_app.dart

// Copyright 2015 The Chromium 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 'dart:async';
import 'dart:ui' as ui;

import 'package:flutter/rendering.dart';
import 'package:flutter/services.dart';
import 'package:flutter/widgets.dart';

import 'page.dart';
import 'theme.dart';

const TextStyle _errorTextStyle = const TextStyle(
  color: const Color(0xD0FF0000),
  fontFamily: 'monospace',
  fontSize: 48.0,
  fontWeight: FontWeight.w900,
  textAlign: TextAlign.right,
  decoration: TextDecoration.underline,
  decorationColor: const Color(0xFFFF00),
  decorationStyle: TextDecorationStyle.double
);

AssetBundle _initDefaultBundle() {
  if (rootBundle != null)
    return rootBundle;
  const String _kAssetBase = '/packages/material_design_icons/icons/';
  return new NetworkAssetBundle(Uri.base.resolve(_kAssetBase));
}

final AssetBundle _defaultBundle = _initDefaultBundle();

class RouteArguments {
  const RouteArguments({ this.context });
  final BuildContext context;
}
typedef Widget RouteBuilder(RouteArguments args);

typedef Future<LocaleQueryData> LocaleChangedCallback(ui.Locale locale);

class MaterialApp extends StatefulComponent {
  MaterialApp({
    Key key,
    this.title,
    this.theme,
    this.routes: const <String, RouteBuilder>{},
    this.onGenerateRoute,
    this.onLocaleChanged
  }) : super(key: key) {
    assert(routes != null);
    assert(routes.containsKey(Navigator.defaultRouteName) || onGenerateRoute != null);
  }

  final String title;
  final ThemeData theme;
  final Map<String, RouteBuilder> routes;
  final RouteFactory onGenerateRoute;
  final LocaleChangedCallback onLocaleChanged;

  _MaterialAppState createState() => new _MaterialAppState();
}

class _MaterialAppState extends State<MaterialApp> implements BindingObserver {

  GlobalObjectKey _navigator;

  Size _size;
  LocaleQueryData _localeData;

  void initState() {
    super.initState();
    _navigator = new GlobalObjectKey(this);
    _size = ui.window.size;
    didChangeLocale(ui.window.locale);
    WidgetFlutterBinding.instance.addObserver(this);
  }

  void dispose() {
    WidgetFlutterBinding.instance.removeObserver(this);
    super.dispose();
  }

  bool didPopRoute() {
    assert(mounted);
    NavigatorState navigator = _navigator.currentState;
    assert(navigator != null);
    navigator.openTransaction((NavigatorTransaction transaction) {
      if (!transaction.pop())
        activity.finishCurrentActivity();
    });
    return true;
  }

  void didChangeSize(Size size) => setState(() { _size = size; });

  void didChangeLocale(ui.Locale locale) {
    if (config.onLocaleChanged != null) {
      config.onLocaleChanged(locale).then((LocaleQueryData data) {
        if (mounted)
          setState(() { _localeData = data; });
      });
    }
  }

  void didChangeAppLifecycleState(ui.AppLifecycleState state) { }

  final HeroController _heroController = new HeroController();

  Route _generateRoute(RouteSettings settings) {
    RouteBuilder builder = config.routes[settings.name];
    if (builder != null) {
      return new MaterialPageRoute(
        builder: (BuildContext context) {
          return builder(new RouteArguments(context: context));
        },
        settings: settings
      );
    }
    if (config.onGenerateRoute != null)
      return config.onGenerateRoute(settings);
    return null;
  }

  Widget build(BuildContext context) {
    if (config.onLocaleChanged != null && _localeData == null) {
      // If the app expects a locale but we don't yet know the locale, then
      // don't build the widgets now.
      return new Container();
    }

    ThemeData theme = config.theme ?? new ThemeData.fallback();
    return new MediaQuery(
      data: new MediaQueryData(size: _size),
      child: new LocaleQuery(
        data: _localeData,
        child: new Theme(
          data: theme,
          child: new DefaultTextStyle(
            style: _errorTextStyle,
            child: new DefaultAssetBundle(
              bundle: _defaultBundle,
              child: new Title(
                title: config.title,
                color: theme.primaryColor,
                child: new Navigator(
                  key: _navigator,
                  initialRoute: ui.window.defaultRouteName,
                  onGenerateRoute: _generateRoute,
                  observer: _heroController
                )
              )
            )
          )
        )
      )
    );
  }

}