全体のコード
まずは結論から。
kotlinのファイルはこちら(引用元:https://qiita.com/mkosuke/items/b384035e507ad0208c10)
package com.example.[プロジェクト名]
import android.content.pm.PackageManager
import androidx.annotation.NonNull
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugin.common.MethodChannel
import kotlinx.coroutines.ExperimentalCoroutinesApi
class MainActivity: FlutterActivity() {
private val CHANNEL = "appInfo"
@OptIn(ExperimentalCoroutinesApi::class)
override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHANNEL).setMethodCallHandler{
call, result ->
println("MethodChannel start")
if(call.method == "getAppVersion"){
println("call getAppVersion start")
try {
val pInfo = applicationContext.packageManager.getPackageInfo(context.packageName, 0)
var version = pInfo.versionName
result.success("${pInfo.versionName}");
} catch (e: PackageManager.NameNotFoundException) {
e.printStackTrace()
result.notImplemented()
}
println("call getAppVersion end")
}else{
result.notImplemented()
}
}
}
}
Flutter(Dart)のファイルはこちら
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'getAppVersion',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
_MyHomePageState() {
getAppVersion();
}
String _appVersion = '';
Future<void> getAppVersion() async {
String appVersion;
print("getAppVersion start");
try {
appVersion = await AppInfo.appVersion ?? 'Unknown App version';
} on PlatformException {
appVersion = 'Failed app version';
}
print("getAppVersion end");
setState(() {
_appVersion = appVersion;
print("appVersion: $_appVersion");
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(),
body: Center(
child: Text(_appVersion, style: const TextStyle(fontSize: 20))),
);
}
}
class AppInfo {
static const MethodChannel _channel = MethodChannel('appInfo');
static Future<String?> get appVersion async {
print("AppInfoClass: appVersion start");
final String? version = await _channel.invokeMethod('getAppVersion');
print("AppInfoClass: appVersion end");
return version;
}
}
考察
MainActivity.kt
configureFlutterEngine
以前はonCreateメソッドで実行していたようだが、現在(2022年6月)ではconfigureFlutterEngineメソッドを使うとのこと。
void configureFlutterEngine (@NonNull FlutterEngine flutterEngine)
Configures the given FlutterEngine.
This method is called after the given FlutterEngine has been attached to the owning FragmentActivity.
FragmentActivityにアクセスしたFlutterEngineが与えられた後に呼ばれるメソッドという感じですかね。
setMethodCallHandlerメソッド
Sets a callback for receiving method calls on this channel.