pkgs/jnigen/example/in_app_java/lib/main.dart

// Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file
// for details. 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:jni/jni.dart';

// The hierarchy created in generated code will mirror the java package
// structure.
import 'android_utils.dart';

JObject activity = JObject.fromReference(Jni.getCurrentActivity());
JObject context = JObject.fromReference(Jni.getCachedApplicationContext());

final hashmap = HashMap.new$2(K: JString.type, V: JString.type);

final emojiCompat = EmojiCompat.get()!;

extension IntX on int {
  JString toJString() {
    return toString().toJString();
  }
}

const sunglassEmoji = "😎";

/// Display device model number and the number of times this was called
/// as Toast.
void showToast() {
  final toastCount =
      hashmap.getOrDefault("toastCount".toJString(), 0.toJString());
  final newToastCount = (int.parse(toastCount!.toDartString()) + 1).toJString();
  hashmap.put("toastCount".toJString(), newToastCount);
  final emoji = emojiCompat.hasEmojiGlyph(sunglassEmoji.toJString())
      ? sunglassEmoji
      : ':cool:';
  final message =
      '${newToastCount.toDartString()} - ${Build.MODEL!.toDartString()} $emoji';
  AndroidUtils.showToast(activity, message.toJString(), 0);
}

void main() {
  EmojiCompat.init(context);
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.teal,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatelessWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            ElevatedButton(
              child: const Text('Show Device Model'),
              onPressed: () => showToast(),
            ),
          ],
        ),
      ),
    );
  }
}