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samples/add_to_app/flutter_module_using_plugin/lib/main.dart

175 lines
5.2 KiB

// Copyright 2019 The Flutter team. 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:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:provider/provider.dart';
import 'package:url_launcher/url_launcher.dart' as launcher;
/// The entrypoint for the flutter module.
void main() {
// This call ensures the Flutter binding has been set up before creating the
// MethodChannel-based model.
WidgetsFlutterBinding.ensureInitialized();
final model = CounterModel();
runApp(
ChangeNotifierProvider.value(
value: model,
child: MyApp(),
),
);
}
/// A simple model that uses a [MethodChannel] as the source of truth for the
/// state of the counter.
///
/// Rather than storing app state data within the Flutter module itself (where
/// the native portions of the app can't access it), this module passes messages
/// back to the containing app whenever it needs to increment or retrieve the
/// value of the counter.
class CounterModel extends ChangeNotifier {
CounterModel() {
_channel.setMethodCallHandler(_handleMessage);
_channel.invokeMethod('requestCounter');
}
final _channel = MethodChannel('dev.flutter.example/counter');
int _count = 0;
int get count => _count;
void increment() {
_channel.invokeMethod('incrementCounter');
}
Future<dynamic> _handleMessage(MethodCall call) async {
if (call.method == 'reportCounter') {
_count = call.arguments as int;
notifyListeners();
}
}
}
/// The "app" displayed by this module.
///
/// It offers two routes, one suitable for displaying as a full screen and
/// another designed to be part of a larger UI.
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Module Title',
routes: {
'/': (context) => FullScreenView(),
'/mini': (context) => Contents(),
},
);
}
}
/// Wraps [Contents] in a Material [Scaffold] so it looks correct when displayed
/// full-screen.
class FullScreenView extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Full-screen Flutter with plugin'),
),
body: const Contents(showExit: true),
);
}
}
/// The actual content displayed by the module.
///
/// This widget displays info about the state of a counter and how much room (in
/// logical pixels) it's been given. It also offers buttons to increment the
/// counter, opening the Flutter documentation via the url_launcher plugin, and
/// (optionally) close the Flutter view.
class Contents extends StatelessWidget {
final bool showExit;
const Contents({this.showExit = false});
@override
Widget build(BuildContext context) {
final mediaInfo = MediaQuery.of(context);
return SizedBox.expand(
child: Stack(
children: [
Positioned.fill(
child: DecoratedBox(
decoration: BoxDecoration(
color: Theme.of(context).scaffoldBackgroundColor,
),
),
),
Positioned.fill(
child: Opacity(
opacity: .25,
child: FittedBox(
fit: BoxFit.cover,
child: FlutterLogo(),
),
),
),
Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(
'Window is ${mediaInfo.size.width.toStringAsFixed(1)} x '
'${mediaInfo.size.height.toStringAsFixed(1)}',
style: Theme.of(context).textTheme.headline,
),
SizedBox(height: 16),
Consumer<CounterModel>(
builder: (context, model, child) {
return Text(
'Taps: ${model.count}',
style: Theme.of(context).textTheme.headline,
);
},
),
SizedBox(height: 16),
Consumer<CounterModel>(
builder: (context, model, child) {
return RaisedButton(
onPressed: () => model.increment(),
child: Text('Tap me!'),
);
},
),
RaisedButton(
onPressed: () async {
// Use the url_launcher plugin to open the Flutter docs in
// a browser.
final url = 'https://flutter.dev/docs';
if (await launcher.canLaunch(url)) {
launcher.launch(url);
}
},
child: Text('Open Flutter Docs'),
),
if (showExit) ...[
SizedBox(height: 16),
RaisedButton(
onPressed: () => SystemNavigator.pop(),
child: Text('Exit this screen'),
),
],
],
),
),
],
),
);
}
}