How to create a service in Flutter to make an app to run always in background?
flutter_background_service
combined with Timer
from dart:async
.
see :
- https://pub.dev/packages/flutter_background_service
- create new Flutter project.
- create
BroadcastReceiver
class besideMainActivity
in android dir. - change
MainActivity.java
andmain.dart
andAndroidManifest.xml
like this
- create
MyReceiver
package com.example.flutter_broadcastreceiver_alarmmanager_repeat;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
public class MyReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
MainActivity.callFlutter();
}
}
MainActivity
package com.example.flutter_broadcastreceiver_alarmmanager_repeat;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Bundle;
import io.flutter.app.FlutterActivity;
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugins.GeneratedPluginRegistrant;
import io.flutter.view.FlutterView;
public class MainActivity extends FlutterActivity {
private PendingIntent pendingIntent;
private AlarmManager alarmManager;
private static FlutterView flutterView;
private static final String CHANNEL = "com.tarazgroup";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
flutterView=getFlutterView();
GeneratedPluginRegistrant.registerWith(this);
Intent intent = new Intent(this, MyReceiver.class);
pendingIntent = PendingIntent.getBroadcast(this, 1019662, intent, 0);
alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
alarmManager.setInexactRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), 1000, pendingIntent);
}
@Override
protected void onDestroy() {
super.onDestroy();
alarmManager.cancel(pendingIntent);
}
static void callFlutter(){
MethodChannel methodChannel=new MethodChannel(flutterView, CHANNEL);
methodChannel.invokeMethod("I say hello every minute!!","");
}
}
main.dart
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key}) : super(key: key);
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
static const methodChannel = const MethodChannel('com.tarazgroup');
_MyHomePageState() {
methodChannel.setMethodCallHandler((call) {
print(call.method);
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
),
body: Container()
);
}
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.flutter_broadcastreceiver_alarmmanager_repeat">
<application
android:name="io.flutter.app.FlutterApplication"
android:icon="@mipmap/ic_launcher"
android:label="flutter_broadcastreceiver_alarmmanager_repeat">
<activity
android:name=".MainActivity"
android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
android:hardwareAccelerated="true"
android:launchMode="singleTop"
android:theme="@style/LaunchTheme"
android:windowSoftInputMode="adjustResize">
<meta-data
android:name="io.flutter.app.android.SplashScreenUntilFirstFrame"
android:value="true" />
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<receiver android:name=".MyReceiver"></receiver>
</application>
</manifest>
your flutter code calls avery 1 min. even your app minimized or switch to another app or screen off.
There isn't a way to do this directly from flutter right now although that may change at some point - see this bug/feature request. You do have a couple of options though.
The first is to use MethodChannels and simply write the android code you want to create a background service (or if you want it to always be a background service you can probably do that without needing communication from the flutter side).
The second is some combination of these two plugins - android_alarm_manager and android_intent. But that won't help for all use-cases.
EDIT Feb 2021:
Flutter now supports running background processes. See this page for details.
This is a library to do just that background_fetch.
Background Fetch is a very simple plugin which will awaken an app in the background about every 15 minutes, providing a short period of background running-time. This plugin will execute your provided callbackFn whenever a background-fetch event occurs. ref