안드로이드 서비스 정의와 생명주기

안드로이드 서비스

 

서비스(Service) 

일반적으로 화면 없이 동작하는 프로그램으로 백그라운드 프로세스(Background Process)라고도 한다. 액티비티 응용 프로그램은 화면(액티비티)이 종료되면 동작하지 않지만 서비스는 백그라운드에서 실행되므로 화면과 상관없이 계속 동작한다.

 

서비스 생명 주기

 

 

화면이 종료되어도 계속되는 음악 서비스 실습

 

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btnStart"
        android:text="음악서비스 시작"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
    <Button
        android:id="@+id/btnStop"
        android:text="음악서비스 중지"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

 

 

MusicService.java

- Service 클래스의 상속을 받는 MusicService 클래스 정의

package com.example.chapter14_1;

import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.IBinder;

public class MusicService extends Service {
    MediaPlayer mp;

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        android.util.Log.i("서비스 테스트", "onCreate()");
        super.onCreate();
    }

    @Override
    public void onDestroy() {
        android.util.Log.i("서비스 테스트", "onDestroy()");
        mp.stop();
        super.onDestroy();
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        android.util.Log.i("서비스 테스트", "onStartCommand()");
        mp = MediaPlayer.create(this, R.raw.song1);
        mp.setLooping(true);
        mp.start();
        return super.onStartCommand(intent, flags, startId);
    }
}

 

 

MainActivity.java

package com.example.chapter14_1;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {
    Intent intent;
    Button btnStart, btnStop;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setTitle("서비스 테스트 예제");

        intent = new Intent(this, MusicService.class);
        btnStart = (Button) findViewById(R.id.btnStart);
        btnStop = (Button) findViewById(R.id.btnStop);

        btnStart.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                startService(intent);
                android.util.Log.i("서비스 테스트", "startService()");
            }
        });
        btnStop.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                stopService(intent);
                android.util.Log.i("서비스 테스트", "stopService()");
            }
        });
    }
}

 

 

AndroidManifest.xml

- uses-sdk와 Service 추가

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.chapter14_1">

    <uses-sdk
        android:targetSdkVersion="16"
        android:minSdkVersion="8" />

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

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

        <service android:name="MusicService">
            <intent-filter>
                <action android:name="com.example.chapter14_1"></action>
            </intent-filter>
        </service>

    </application>

</manifest>

 

---

 

배터리상태 체크 예제

가상폰 옆의 ...을 누르면 배터리 잔량을 조절해 볼 수 있습니다.

 

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

   <ImageView
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:id="@+id/ivBattery"
       android:layout_gravity="center"
       android:src="@drawable/battery_0"/>

    <EditText
        android:id="@+id/edtBattery"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#cccccc"
        android:enabled="false"/>

</LinearLayout>

 

MainActivity.java

package com.example.chapter14_6;

import androidx.appcompat.app.AppCompatActivity;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.BatteryManager;
import android.os.Bundle;
import android.widget.EditText;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {
    ImageView ivBattery;
    EditText edtBattery;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setTitle("배터리 상태 체크");

        ivBattery = (ImageView)findViewById(R.id.ivBattery);
        edtBattery = (EditText)findViewById(R.id.edtBattery);
    }

    @Override
    protected void onPause() {
        super.onPause();
        unregisterReceiver(br);
    }

    @Override
    protected void onPostResume() {
        super.onPostResume();
        IntentFilter iFilter = new IntentFilter();
        iFilter.addAction(Intent.ACTION_BATTERY_CHANGED);
        registerReceiver(br, iFilter);
    }

    BroadcastReceiver br = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if(action.equals(Intent.ACTION_BATTERY_CHANGED)){
                int remain = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);
                edtBattery.append("현재 충전량: "+remain+" %\n");

                if(remain >=90)
                    ivBattery.setImageResource(R.drawable.battery_100);
                else if(remain>=70)
                    ivBattery.setImageResource(R.drawable.battery_80);
                else if(remain>=50)
                    ivBattery.setImageResource(R.drawable.battery_60);
                else if(remain>=10)
                    ivBattery.setImageResource(R.drawable.battery_20);
                else
                    ivBattery.setImageResource(R.drawable.battery_0);
                int plug = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, 0);
                switch (plug) {
                    case 0:
                        edtBattery.append("전원 연결 : 안됨");
                        break;
                    case BatteryManager.BATTERY_PLUGGED_AC:
                        edtBattery.append("전원 연결 : 어댑터 연결됨");
                        break;
                    case BatteryManager.BATTERY_PLUGGED_USB:
                        edtBattery.append("전원 연결 : USB 연결됨");
                        break;
                }
            }
        }
    };
}

 

실습파일.zip

0.34MB