Android – How to create a service run after rebooting the phone?

How to create a service like that?

• Create a Notification channel

public class MyApp extends Application {
    public static final String CHANNEL_ID = "autoStartServiceChannel";
    public static final String CHANNEL_NAME = "Auto Start Service Channel";
    @Override
    public void onCreate() {
        super.onCreate();
        createNotificationChannel();
    }

    private void createNotificationChannel() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationChannel serviceChannel = new NotificationChannel(
                    CHANNEL_ID,
                    CHANNEL_NAME,
                    NotificationManager.IMPORTANCE_DEFAULT
            );
            NotificationManager manager = getSystemService(NotificationManager.class);
            manager.createNotificationChannel(serviceChannel);
        }
    }
}

• Create a Service and call a local notification with startForeground

public class AutoStartService extends Service {
    @Override
    public void onCreate() {
        super.onCreate();
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        String input = intent.getStringExtra("inputExtra");
        Intent notificationIntent = new Intent(this, MainActivity.class);
        PendingIntent pendingIntent = PendingIntent.getActivity(this,
                0, notificationIntent, 0);
        Notification notification = new NotificationCompat.Builder(this, MyApp.CHANNEL_ID)
                .setContentTitle("Auto Start Service")
                .setContentText(input)
                .setSmallIcon(R.drawable.ic_launcher_background)
                .setContentIntent(pendingIntent)
                .build();
        NotificationManager  mNotificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationChannel channel = new NotificationChannel( MyApp.CHANNEL_ID, MyApp.CHANNEL_NAME, NotificationManager.IMPORTANCE_DEFAULT);
            mNotificationManager.createNotificationChannel(channel);
            new NotificationCompat.Builder(this, MyApp.CHANNEL_ID);
        }
        startForeground(1, notification);
        return START_NOT_STICKY;
    }
    @Override
    public void onDestroy() {
        super.onDestroy();
    }
    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
}

• Start the above service with startForegroundService

        Intent serviceIntent = new Intent(this, AutoStartService.class);
        serviceIntent.putExtra("inputExtra", "passing any text");
        ContextCompat.startForegroundService(this, serviceIntent);

• Create a BroadcastReceiver to start the service with startForegroundService

public class AutoStartReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        Intent serviceIntent = new Intent(context, AutoStartService.class);
        serviceIntent.putExtra("inputExtra", "passing any text");
        ContextCompat.startForegroundService(context, serviceIntent);
    }
}

• Add the following into AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.myapp">

    <uses-permission android:name="android.permission.FOREGROUND_SERVICE"/>
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

    <application
        android:name=".MyApp"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.MyApp">

        <receiver
            android:name=".AutoStartReceiver"
            android:enabled="true"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED" />
            </intent-filter>
        </receiver>

        <service
            android:name=".AutoStartService"
            android:enabled="true"
            android:exported="true" />

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

https://github.com/hung-nb/android-foreground-service

How to keep service running while screen off?

PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "My Tag");
wl.acquire();
// ..cpu will stay running on during this section..
wl.release();

 if you want to keep your service always running, acquire your lock in onStartCommand() and release in onDestroy()