08. 뮤직 플레이어 MediaPlayer API, 서비스

8.3 준비하기: 프로젝트

8.4 레이아웃 구성하기

8.4.1 레이아웃 팔레트를 사용해 버튼 생성하기

8.4.2 버튼 속 텍스트를 리소스 파일을 사용해 지정하기

strings.xml

<resources>
    <string name="app_name">SimpleMusicPlayer</string>
    <string name="btn_play">재생</string>
    <string name="btn_pause">일시정지</string>
    <string name="btn_stop">재생중지</string>
</resources>

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btn_play"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/btn_play"
        app:layout_constraintBottom_toTopOf="@+id/button2"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="120dp"
        android:text="@string/btn_pause"
        app:layout_constraintBottom_toTopOf="@+id/button3"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/btn_play" />
    
    <Button
        android:id="@+id/button3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="120dp"
        android:text="@string/btn_stop"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button2" />
</androidx.constraintlayout.widget.ConstraintLayout>

8.5 리소스 준비하기

8.5.1 MP3 파일 준비하기

8.5.2 아이콘 준비하기

8.6 서비스 클래스 구현하기

MusicPlayerService.kt

package com.example.simplemusicplayer

import android.app.Notification
import android.app.NotificationChannel
import android.app.NotificationManager
import android.app.Service
import android.content.Intent
import android.media.MediaPlayer
import android.os.Binder
import android.os.Build
import android.os.IBinder
import android.widget.Toast

class MusicPlayerService : Service() {

    var mMediaPlayer: MediaPlayer? = null // 미디어 플레이어 객체를 null로 초기화

    var mBinder: MusicPlayerBinder = MusicPlayerBinder()

    inner class MusicPlayerBinder : Binder() {
        fun getService(): MusicPlayerService {
            return this@MusicPlayerService
        }
    }

    override fun onCreate() {
        super.onCreate()
        startForegroundService()
    }

    override fun onBind(intent: Intent?): IBinder? {
        TODO("Not yet implemented")
    }

    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
        return START_STICKY
    }

    fun startForegroundService() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            val notificationManager = getSystemService(NOTIFICATION_SERVICE) as NotificationManager
            val mChannel = NotificationChannel(
                "CHANNEL_ID",
                "CHANNEL_NAME",
                NotificationManager.IMPORTANCE_DEFAULT
            )
            notificationManager.createNotificationChannel(mChannel)
        }

        val notification: Notification = Notification.Builder(this, "CHANNEL_ID")
            .setSmallIcon(R.drawable.baseline_play_arrow_24)
            .setContentTitle("뮤직 플레이어 앱")
            .setContentText("앱이 실행 중입니다.")
            .build()

        startForeground(1, notification)
    }

    override fun onDestroy() {
        super.onDestroy()
        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            stopForeground(true);
        }
    }

    fun isPlaying() : Boolean {
        return (mMediaPlayer != null && mMediaPlayer?.isPlaying ?: false)
    }

    fun play() {
        if (mMediaPlayer == null) {
            mMediaPlayer = MediaPlayer.create(this, R.raw.chocolate)
            
            mMediaPlayer?.setVolume(1.0f, 1.0f);
            mMediaPlayer?.isLooping = true
            mMediaPlayer?.start()
        } else {
            if(mMediaPlayer!!.isPlaying) {
                Toast.makeText(this, "이미 음악이 실행 중입니다.",
                    Toast.LENGTH_SHORT).show()
            } else {
                mMediaPlayer?.start()
            }
        }
    }
    
    fun pause() {
        mMediaPlayer?.let {
            if (it.isPlaying) {
                it.pause()
            }
        }    
    }
    
    fun stop() {
        mMediaPlayer?.let {
            if (it.isPlaying) {
                it.stop()
                it.release()
                mMediaPlayer = null
            }
        }
    }
}

AndroidManifest.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">

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.SimpleMusicPlayer"
        tools:targetApi="31">
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

8.7 버튼 초기화하기

MainActivity.kt

package com.example.simplemusicplayer

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.Button

class MainActivity : AppCompatActivity(), View.OnClickListener {
    lateinit var btn_play : Button
    lateinit var btn_pause : Button
    lateinit var btn_stop : Button
    
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        
        btn_play = findViewById(R.id.btn_play)
        btn_pause = findViewById(R.id.btn_pause)
        btn_stop = findViewById(R.id.btn_stop)
        
        btn_play.setOnClickListener(this)
        btn_pause.setOnClickListener(this)
        btn_stop.setOnClickListener(this)
    }

    override fun onClick(v: View?) {
        when(v?.id) {
            R.id.btn_play -> {
                play()
            }
            
            R.id.btn_pause -> {
                pause()
            }
            
            R.id.btn_stop -> {
                stop()
            }
        }
    }

    override fun onResume() {
        super.onResume()
    }

    override fun onPause() {
        super.onPause()
    }
    
    private fun play() {
        
    }
    
    private fun pause() {
        
    }
    
    private fun stop() {
        
    }
}

8.8 액티비티와 서비스 연결하기

MainActivity.kt

package com.example.simplemusicplayer

import android.content.ComponentName
import android.content.Context
import android.content.Intent
import android.content.ServiceConnection
import android.os.Build
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.os.IBinder
import android.view.View
import android.widget.Button

class MainActivity : AppCompatActivity(), View.OnClickListener {
    lateinit var btn_play : Button
    lateinit var btn_pause : Button
    lateinit var btn_stop : Button
    var mService: MusicPlayerService? = null
    
    val mServiceConnection = object : ServiceConnection {
        override fun onServiceConnected(name: ComponentName?, service: IBinder?) {
            mService = (service as MusicPlayerService.MusicPlayerBinder).getService()
        }
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        btn_play = findViewById(R.id.btn_play)
        btn_pause = findViewById(R.id.btn_pause)
        btn_stop = findViewById(R.id.btn_stop)

        btn_play.setOnClickListener(this)
        btn_pause.setOnClickListener(this)
        btn_stop.setOnClickListener(this)
    }

    override fun onClick(v: View?) {
        when(v?.id) {
            R.id.btn_play -> {
                play()
            }

            R.id.btn_pause -> {
                pause()
            }

            R.id.btn_stop -> {
                stop()
            }
        }
    }

    override fun onResume() {
        super.onResume()
        
        if(mService == null) {
            if(Build.VERSION.SDK_INT > Build.VERSION_CODES.O) {
                startForegroundService(Intent(this, MusicPlayerService::class.java))
            } else {
                startService(Intent(applicationContext, MusicPlayerService::class.java))
            }
            
            val intent = Intent(this, MusicPlayerService::class.java)
            bindService(intent, mServiceConnection, Context.BIND_AUTO_CREATE)
        }
    }

    override fun onPause() {
        super.onPause()
        if (mService != null) {
            if (!mService!!.isPlaying()) {
                mService!!.stopSelf()
            }
            unbindService(mServiceConnection)
            mService = null
        }
    }

    private fun play() {
        mService?.play()
    }

    private fun pause() {
        mService?.pause()
    }

    private fun stop() {
        mService?.stop()
    }
}

---

09. QR 코드 리더기 카메라, 뷰 바인딩, 구글 ML 키트

9.4 사전 지식: 구글 ML 키트

1. 바코드 스캐닝 API: 바코드를 스캔하고 해석하는 API를 제공합니다. 우리가 이번 앱에서 사용할 API입니다.
2. 얼굴 인식 API: 얼굴을 인식하거나 얼굴의 요소들을 인식합니다.
3. 텍스트 인식 API: 이미지로부터 텍스트를 인식하거나 추출합니다.
4. 포즈 인식 API: 사람 몸의 자세를 실시간으로 인식합니다.
5. 언어 감지 API: 주어진 텍스트가 쓰여진 언어가 무엇인지를 알려줍니다.

9.5 준비하기: 프로젝트, 뷰 바인딩, 라이브러리

9.5.2 뷰 바인딩 설정과 라이브러리 추가

build.gradle

plugins {
    id 'com.android.application'
    id 'org.jetbrains.kotlin.android'
}

android {
    namespace 'com.example.qrcodereader'
    compileSdk 34

    defaultConfig {
        applicationId "com.example.qrcodereader"
        minSdk 26
        targetSdk 34
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = '1.8'
    }
    buildFeatures {
        viewBinding true
    }
}

dependencies {
    def camerax_version = "1.1.0-alpha04"
    implementation "androidx.camera:camera-camera2:$camerax_version"
    implementation "androidx.camera:camera-lifecycle:$camerax_version"
    implementation "androidx.camera:camera-view:1.0.0-alpha24"
    implementation "com.google.mlkit:barcode-scanning:16.1.1"

    implementation 'androidx.core:core-ktx:1.12.0'
    implementation 'androidx.appcompat:appcompat:1.6.1'
    implementation 'com.google.android.material:material:1.11.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.1.4'
    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.5'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.5.1'
}

9.6 레이아웃 구성하기

9.6.1 MainAtivity 레이아웃 작성하기

activity_main.xml

package com.example.qrcodereader

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }
}

9.6.2 ResultActivity 레이아웃 작성하기

activity_result.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
    tools:context=".ResultActivity">

    <TextView
        android:id="@+id/tv_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="168dp"
        android:text="결과값 :"
        android:textSize="24sp"
        android:textStyle="bold"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/tv_content"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="48dp"
        android:text="결과값이 들어갈 자리"
        android:textSize="18sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tv_title" />

    <Button
        android:id="@+id/btn_go_back"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="68dp"
        android:text="돌아가기"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />


</androidx.constraintlayout.widget.ConstraintLayout>

9.7 카메라 미리보기 화면 구현하기

9.7.1 미리보기 구현하기

MainActivity.kt

package com.example.qrcodereader

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import androidx.camera.core.CameraSelector
import androidx.camera.core.Preview
import androidx.camera.lifecycle.ProcessCameraProvider
import androidx.core.content.ContextCompat
import com.example.qrcodereader.databinding.ActivityMainBinding
import com.google.common.util.concurrent.ListenableFuture

class MainActivity : AppCompatActivity() {

    private lateinit var binding : ActivityMainBinding
    private lateinit var cameraProviderFuture : ListenableFuture<ProcessCameraProvider>

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        
        binding = ActivityMainBinding.inflate(layoutInflater)
        val view = binding.root
        setContentView(view)
        
        startCamera()
        
    }

    fun startCamera() {
        cameraProviderFuture = ProcessCameraProvider.getInstance(this)
        cameraProviderFuture.addListener(Runnable {
            val cameraProvider = cameraProviderFuture.get()
            
            val preview = getPreview()
            val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA
            
            cameraProvider.bindToLifecycle(this, cameraSelector,preview)
        }, ContextCompat.getMainExecutor(this))
    }

    fun getPreview(): Preview {

        val preview : Preview = Preview.Builder().build()
        preview.setSurfaceProvider(binding.barcodePreview.getSurfaceProvider())

        return preview
    }
}

9.7.2 카메라 권한 승인하기

AndroidMAnifest.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">
    
    <uses-feature android:name="android.hardware.camera" />
    <uses-permission android:name="android.permission.CAMERA" />
    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.QRCodeReader"
        tools:targetApi="31">
        <activity
            android:name=".ResultActivity"
            android:exported="false" />
        <activity
            android:name=".MainActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>

9.7.3 MainActivity.kt 전체코드

MainActivity.kt

package com.example.qrcodereader

import android.Manifest
import android.content.Context
import android.content.pm.PackageManager
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Toast
import androidx.camera.core.CameraSelector
import androidx.camera.core.Preview
import androidx.camera.lifecycle.ProcessCameraProvider
import androidx.core.content.ContextCompat
import com.example.qrcodereader.databinding.ActivityMainBinding
import com.google.common.util.concurrent.ListenableFuture

class MainActivity : AppCompatActivity() {

    private lateinit var binding : ActivityMainBinding
    private lateinit var cameraProviderFuture : ListenableFuture<ProcessCameraProvider>

    private val PERMISSIONS_REQUEST_CODE = 1
    private val PERMISSIONS_REQUIRED = arrayOf(Manifest.permission.CAMERA)

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        binding = ActivityMainBinding.inflate(layoutInflater)
        val view = binding.root
        setContentView(view)

        if (!hasPermissions(this)) {
            requestPermissions(PERMISSIONS_REQUIRED, PERMISSIONS_REQUEST_CODE)
        } else {
            startCamera()
        }

    }

    fun hasPermissions(context: Context) = PERMISSIONS_REQUIRED.all {
        ContextCompat.checkSelfPermission(context, it) ==
                PackageManager.PERMISSION_GRANTED
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        if (requestCode == PERMISSIONS_REQUEST_CODE) {
            if(PackageManager.PERMISSION_GRANTED == grantResults.firstOrNull()) {
                Toast.makeText(this@MainActivity, "권한 요청이 승인되었습니다.",
                    Toast.LENGTH_LONG).show()
                finish()
            }
        }
    }

    fun startCamera() {
        cameraProviderFuture = ProcessCameraProvider.getInstance(this)
        cameraProviderFuture.addListener(Runnable {
            val cameraProvider = cameraProviderFuture.get()

            val preview = getPreview()
            val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA

            cameraProvider.bindToLifecycle(this, cameraSelector,preview)
        }, ContextCompat.getMainExecutor(this))
    }

    fun getPreview(): Preview {

        val preview : Preview = Preview.Builder().build()
        preview.setSurfaceProvider(binding.barcodePreview.getSurfaceProvider())

        return preview
    }
}

9.8 QR 코드 인식 기능 구현하기

OnDetectListener.kt

package com.example.qrcodereader

interface OnDetectListener {
    fun onDetect(msg : String)
}

MainActivity.kt

package com.example.qrcodereader

import android.Manifest
import android.content.Context
import android.content.pm.PackageManager
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Toast
import androidx.camera.core.CameraSelector
import androidx.camera.core.ImageAnalysis
import androidx.camera.core.Preview
import androidx.camera.lifecycle.ProcessCameraProvider
import androidx.core.content.ContextCompat
import com.example.qrcodereader.databinding.ActivityMainBinding
import com.google.common.util.concurrent.ListenableFuture
import java.util.concurrent.ExecutorService
import java.util.concurrent.Executors

class MainActivity : AppCompatActivity() {

    private lateinit var binding : ActivityMainBinding
    private lateinit var cameraProviderFuture : ListenableFuture<ProcessCameraProvider>

    private val PERMISSIONS_REQUEST_CODE = 1
    private val PERMISSIONS_REQUIRED = arrayOf(Manifest.permission.CAMERA)

    fun getImageAnalysis() : ImageAnalysis {
        val cameraExecutor: ExecutorService = Executors.newSingleThreadExecutor()
        val imageAnalysis = ImageAnalysis.Builder().build()

        imageAnalysis.setAnalyzer(cameraExecutor, QRCodeAnalyzer(object : OnDetectListener {
            override fun onDetect(msg: String) {
                Toast.makeText(this@MainActivity, "${msg}", Toast.LENGTH_SHORT).show()
            }
        }))
        return imageAnalysis
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        binding = ActivityMainBinding.inflate(layoutInflater)
        val view = binding.root
        setContentView(view)

        if (!hasPermissions(this)) {
            requestPermissions(PERMISSIONS_REQUIRED, PERMISSIONS_REQUEST_CODE)
        } else {
            startCamera()
        }

    }

    fun hasPermissions(context: Context) = PERMISSIONS_REQUIRED.all {
        ContextCompat.checkSelfPermission(context, it) ==
                PackageManager.PERMISSION_GRANTED
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        if (requestCode == PERMISSIONS_REQUEST_CODE) {
            if(PackageManager.PERMISSION_GRANTED == grantResults.firstOrNull()) {
                Toast.makeText(this@MainActivity, "권한 요청이 승인되었습니다.",
                    Toast.LENGTH_LONG).show()
                finish()
            }
        }
    }

    fun startCamera() {
        cameraProviderFuture = ProcessCameraProvider.getInstance(this)
        cameraProviderFuture.addListener(Runnable {
            val cameraProvider = cameraProviderFuture.get()

            val preview = getPreview()
            val imageAnalysis = getImageAnalysis()
            val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA

            cameraProvider.bindToLifecycle(this, cameraSelector,preview,imageAnalysis)
        }, ContextCompat.getMainExecutor(this))
    }

    fun getPreview(): Preview {

        val preview : Preview = Preview.Builder().build()
        preview.setSurfaceProvider(binding.barcodePreview.getSurfaceProvider())

        return preview
    }
}

9.9 결과 화면 구현하기

package com.example.qrcodereader

import android.Manifest
import android.content.Context
import android.content.Intent
import android.content.pm.PackageManager
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Toast
import androidx.camera.core.CameraSelector
import androidx.camera.core.ImageAnalysis
import androidx.camera.core.Preview
import androidx.camera.lifecycle.ProcessCameraProvider
import androidx.core.content.ContextCompat
import com.example.qrcodereader.databinding.ActivityMainBinding
import com.google.common.util.concurrent.ListenableFuture
import java.util.concurrent.ExecutorService
import java.util.concurrent.Executors

class MainActivity : AppCompatActivity() {

    private lateinit var binding : ActivityMainBinding
    private lateinit var cameraProviderFuture : ListenableFuture<ProcessCameraProvider>

    private val PERMISSIONS_REQUEST_CODE = 1
    private val PERMISSIONS_REQUIRED = arrayOf(Manifest.permission.CAMERA)
    
    private var isDetected = false
    
    override fun onResume() {
        super.onResume()
        isDetected=false
    }

    fun getImageAnalysis() : ImageAnalysis {
        val cameraExecutor: ExecutorService = Executors.newSingleThreadExecutor()
        val imageAnalysis = ImageAnalysis.Builder().build()

        imageAnalysis.setAnalyzer(cameraExecutor, QRCodeAnalyzer(object : OnDetectListener {
            override fun onDetect(msg: String) {
                if(!isDetected) {
                    isDetected = true
                    
                    val intent = Intent(this@MainActivity,
                        ResultActivity::class.java)
                    intent.putExtra("msg", msg)
                    startActivity(intent)
                }
                Toast.makeText(this@MainActivity, "${msg}", Toast.LENGTH_SHORT).show()
            }
        }))
        return imageAnalysis
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        binding = ActivityMainBinding.inflate(layoutInflater)
        val view = binding.root
        setContentView(view)

        if (!hasPermissions(this)) {
            requestPermissions(PERMISSIONS_REQUIRED, PERMISSIONS_REQUEST_CODE)
        } else {
            startCamera()
        }

    }

    fun hasPermissions(context: Context) = PERMISSIONS_REQUIRED.all {
        ContextCompat.checkSelfPermission(context, it) ==
                PackageManager.PERMISSION_GRANTED
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        if (requestCode == PERMISSIONS_REQUEST_CODE) {
            if(PackageManager.PERMISSION_GRANTED == grantResults.firstOrNull()) {
                Toast.makeText(this@MainActivity, "권한 요청이 승인되었습니다.",
                    Toast.LENGTH_LONG).show()
                finish()
            }
        }
    }

    fun startCamera() {
        cameraProviderFuture = ProcessCameraProvider.getInstance(this)
        cameraProviderFuture.addListener(Runnable {
            val cameraProvider = cameraProviderFuture.get()

            val preview = getPreview()
            val imageAnalysis = getImageAnalysis()
            val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA

            cameraProvider.bindToLifecycle(this, cameraSelector,preview,imageAnalysis)
        }, ContextCompat.getMainExecutor(this))
    }

    fun getPreview(): Preview {

        val preview : Preview = Preview.Builder().build()
        preview.setSurfaceProvider(binding.barcodePreview.getSurfaceProvider())

        return preview
    }
}