Background Service(JobIntentService) + BroadcastReceiver

AlarmService.java

package com.health.myapplication.alarm;

import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.os.Build;

import androidx.annotation.NonNull;
import androidx.core.app.JobIntentService;
import androidx.core.app.NotificationCompat;
import androidx.core.app.TaskStackBuilder;

import com.health.myapplication.R;
import com.health.myapplication.activity.MainActivity;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;

public class AlarmService extends JobIntentService {
    static final int JOB_ID = 1001;
    private Calendar calendar;


    //receiver에서 실행하는 함수
    static void enqueueWork(Context context, Intent work) {
        enqueueWork(context, AlarmService.class, JOB_ID, work);
    }

    @Override
    protected void onHandleWork(@NonNull Intent intent) {
        calendar=Calendar.getInstance();
        notification("HEALTH-ER", "message", AlarmService.this); //notification 함수
        stopSelf();
    }



    public void notification(String title, String message, Context context) {
        String text = "더 쉬면 근손실.";
        NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

        int notificationId = createID();
        String channelId = "channel-id";
        String channelName = "Channel Name";
        int importance = NotificationManager.IMPORTANCE_HIGH;

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationChannel mChannel = new NotificationChannel(
                    channelId, channelName, importance);
            notificationManager.createNotificationChannel(mChannel);
        }

        NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(context, channelId)
                .setContentTitle(title)
                .setContentText(text)
                .setVibrate(new long[]{100, 250})
                .setLights(Color.YELLOW, 500, 5000)
                .setAutoCancel(true);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            mBuilder.setSmallIcon(R.drawable.noti);
            mBuilder.setColor(getResources().getColor(R.color.colorPrimaryDark));
        } else {
            mBuilder.setSmallIcon(R.drawable.noti);
        }
        TaskStackBuilder stackBuilder = TaskStackBuilder.create(context);
        stackBuilder.addNextIntent(new Intent(context, MainActivity.class));
        PendingIntent resultPendingIntent = stackBuilder.getPendingIntent(0,PendingIntent.FLAG_UPDATE_CURRENT);
        mBuilder.setContentIntent(resultPendingIntent);

        notificationManager.notify(notificationId, mBuilder.build());
    }

    public int createID() {
        Date now = new Date();
        int id = Integer.parseInt(new SimpleDateFormat("ddHHmmss", Locale.KOREA).format(now));
        return id;
    }
}

MainActivity.java

startButton.setOnClickListener{
            // Creating the pending intent to send to the BroadcastReceiver
            try {
                alarmManager = getSystemService(Context.ALARM_SERVICE) as AlarmManager
                val intent = Intent(this, MyAlarmReceiver::class.java)
                pendingIntent = PendingIntent.getBroadcast(this, REQUEST_CODE, intent, PendingIntent.FLAG_UPDATE_CURRENT)

                // Setting the specific time for the alarm manager to trigger the intent
                val calendar = Calendar.getInstance()
                calendar.timeInMillis = System.currentTimeMillis()

                //0~60초, 분 이내의 시간 입력
                if(Integer.parseInt(secondEditText.text.toString())>60 || Integer.parseInt(secondEditText.text.toString())<0 ||
                        Integer.parseInt(minuteEditText.text.toString())>60 || Integer.parseInt(minuteEditText.text.toString())<0 ){
                    Toast.makeText(this@MainActivity, "올바른 시간을 입력하세요.", Toast.LENGTH_LONG).show()
                }
                else {
                    calendar.add(Calendar.SECOND, Integer.parseInt(secondEditText.text.toString()))
                    calendar.add(Calendar.MINUTE, Integer.parseInt(minuteEditText.text.toString()))

                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
                        alarmManager.setExact(AlarmManager.RTC_WAKEUP, calendar.timeInMillis, pendingIntent)
                    } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                        alarmManager.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, calendar.timeInMillis, pendingIntent)
                    } else {
                        alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.timeInMillis, pendingIntent)
                    }

                    Toast.makeText(this@MainActivity, minuteEditText.text.toString() + "분 " + secondEditText.text.toString() + "초 뒤에 알람이 울립니다", Toast.LENGTH_SHORT).show()
                }
            }catch (e: Exception) {
                Toast.makeText(this@MainActivity, "알람 설정 오류", Toast.LENGTH_SHORT).show()
            }
        }

Manifest.xml

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

    <!--  진동 허용, 부팅 시 receive 허용, 화면 out 상태에서 켜짐 허용 -->
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
    <uses-permission android:name="android.permission.VIBRATE" />
    <application
        ...
        <receiver android:name=".alarm.MyAlarmReceiver"/>

        <service
            android:name=".alarm.AlarmService"
            android:enabled="true"
            android:exported="false"
            android:permission="android.permission.BIND_JOB_SERVICE" />
    </application>
</manifest>

MyAlarmReceiver.java

package com.health.myapplication.alarm;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;

public class MyAlarmReceiver extends BroadcastReceiver {
    private static Context context;

    @Override
    public void onReceive(Context context, Intent intent) {
        //Receiver가 알람을 받음
        this.context = context;
        Intent service_intent = new Intent(context, AlarmService.class);
        AlarmService.enqueueWork(context,service_intent); //service 시작

    }
}