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

// app/build.gradle
plugins {
  id 'com.android.application'
  id 'kotlin-android'
}
 
android {
  compileSdk 34
  defaultConfig {
    applicationId "com.example.screenrecorder"
    minSdk 23
    targetSdk 34
  }
  buildFeatures { viewBinding true }
}
 
dependencies {
  implementation "androidx.appcompat:appcompat:1.6.1"
  implementation "androidx.core:core-ktx:1.10.1"
  implementation "androidx.lifecycle:lifecycle-runtime-ktx:2.6.1"
}

// =======================================================
// 文件：AndroidManifest.xml
// 描述：權限申請與 Service 聲明
// =======================================================
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.screenrecorder">
 
  <uses-permission android:name="android.permission.FOREGROUND_SERVICE"/>
  <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
  <uses-permission android:name="android.permission.RECORD_AUDIO"/>
 
  <application
      android:name=".App"
      android:theme="@style/Theme.ScreenRecorder">
    <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=".ScreenRecordService"
        android:exported="false"/>
  </application>
</manifest>
 
// =======================================================
// 文件：App.kt
// 描述：Application，用于初始化通知渠道
// =======================================================
package com.example.screenrecorder
 
import android.app.Application
import android.app.NotificationChannel
import android.app.NotificationManager
import android.os.Build
 
class App : Application() {
  companion object { const val CHANNEL_ID = "screen_recorder_channel" }
  override fun onCreate() {
    super.onCreate()
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
      NotificationManager::class.java
        .getSystemService(NotificationManager::class.java)
        .createNotificationChannel(
          NotificationChannel(
            CHANNEL_ID,
            "Screen Recorder Service",
            NotificationManager.IMPORTANCE_LOW
          )
        )
    }
  }
}
 
// =======================================================
// 文件：res/values/themes.xml
// 描述：應用主題
// =======================================================
<resources>
  <style name="Theme.ScreenRecorder" parent="Theme.MaterialComponents.DayNight.NoActionBar"/>
</resources>
 
// =======================================================
// 文件：res/layout/activity_main.xml
// 描述：主界面，控制錄制與播放
// =======================================================
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent" android:layout_height="match_parent"
    android:padding="24dp">
 
  <LinearLayout
      android:layout_width="match_parent" android:layout_height="wrap_content"
      android:orientation="vertical" android:gravity="center">
 
    <Button
        android:id="@+id/btnStart"
        android:layout_width="wrap_content" android:layout_height="wrap_content"
        android:text="開始錄制"/>
 
    <Button
        android:id="@+id/btnStop"
        android:layout_width="wrap_content" android:layout_height="wrap_content"
        android:text="停止錄制"
        android:layout_marginTop="16dp"
        android:enabled="false"/>
 
    <TextView
        android:id="@+id/tvPath"
        android:layout_width="match_parent" android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:text="錄制路徑："/>
  </LinearLayout>
</FrameLayout>
 
// =======================================================
// 文件：MainActivity.kt
// 描述：申請權限、發(fā)起錄屏授權、啟動/停止 Service
// =======================================================
package com.example.screenrecorder
 
import android.app.Activity
import android.content.Intent
import android.media.projection.MediaProjectionManager
import android.os.Bundle
import androidx.activity.result.contract.ActivityResultContracts
import androidx.appcompat.app.AppCompatActivity
import androidx.core.app.ActivityCompat
import com.example.screenrecorder.databinding.ActivityMainBinding
 
class MainActivity : AppCompatActivity() {
  private lateinit var b: ActivityMainBinding
  private lateinit var projectionManager: MediaProjectionManager
  private var resultCode = Activity.RESULT_CANCELED
  private var resultData: Intent? = null
 
  private val reqStorage = registerForActivityResult(
    ActivityResultContracts.RequestPermission()
  ) { granted ->
    if (!granted) finish()
  }
 
  private val reqScreen = registerForActivityResult(
    ActivityResultContracts.StartActivityForResult()
  ) { res ->
    if (res.resultCode == Activity.RESULT_OK) {
      resultCode = res.resultCode
      resultData = res.data
      startService()
    }
  }
 
  override fun onCreate(s: Bundle?) {
    super.onCreate(s)
    b = ActivityMainBinding.inflate(layoutInflater)
    setContentView(b.root)
 
    projectionManager = getSystemService(MEDIA_PROJECTION_SERVICE)
      as MediaProjectionManager
 
    reqStorage.launch(android.Manifest.permission.WRITE_EXTERNAL_STORAGE)
 
    b.btnStart.setOnClickListener {
      reqScreen.launch(projectionManager.createScreenCaptureIntent())
    }
    b.btnStop.setOnClickListener {
      stopService(Intent(this, ScreenRecordService::class.java))
    }
  }
 
  private fun startService() {
    val intent = Intent(this, ScreenRecordService::class.java).apply {
      putExtra("code", resultCode)
      putExtra("data", resultData)
    }
    startService(intent)
    b.btnStart.isEnabled = false
    b.btnStop.isEnabled = true
  }
}
 
// =======================================================
// 文件：ScreenRecordService.kt
// 描述：前臺 Service，管理 MediaRecorder 與 MediaProjection
// =======================================================
package com.example.screenrecorder
 
import android.app.Notification
import android.app.PendingIntent
import android.app.Service
import android.content.Intent
import android.hardware.display.DisplayManager
import android.hardware.display.MediaProjection
import android.hardware.display.MediaProjectionManager
import android.hardware.display.VirtualDisplay
import android.media.MediaRecorder
import android.os.*
import android.provider.MediaStore
import androidx.core.app.NotificationCompat
import java.io.File
import java.text.SimpleDateFormat
import java.util.*
 
class ScreenRecordService : Service() {
  private lateinit var recorder: MediaRecorder
  private var projection: MediaProjection? = null
  private var virtualDisplay: VirtualDisplay? = null
  private lateinit var projectionManager: MediaProjectionManager
  private lateinit var outputFile: String
 
  override fun onCreate() {
    super.onCreate()
    projectionManager = getSystemService(MEDIA_PROJECTION_SERVICE)
      as MediaProjectionManager
    recorder = MediaRecorder()
  }
 
  override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
    val code = intent?.getIntExtra("code", -1) ?: -1
    val data = intent?.getParcelableExtra<Intent>("data")
    if (code != -1 && data != null) {
      initRecorder()
      projection = projectionManager.getMediaProjection(code, data)
      virtualDisplay = projection?.createVirtualDisplay(
        "ScreenRecorder",
        recorder.videoWidth, recorder.videoHeight, resources.displayMetrics.densityDpi,
        DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,
        recorder.surface, null, null
      )
      recorder.start()
      startForeground(1, buildNotification())
    }
    return START_NOT_STICKY
  }
 
  private fun initRecorder() {
    val metrics = resources.displayMetrics
    val width = metrics.widthPixels
    val height = metrics.heightPixels
    recorder.apply {
      setAudioSource(MediaRecorder.AudioSource.MIC)
      setVideoSource(MediaRecorder.VideoSource.SURFACE)
      setOutputFormat(MediaRecorder.OutputFormat.MPEG_4)
      outputFile = createOutputFile()
      setOutputFile(outputFile)
      setVideoEncoder(MediaRecorder.VideoEncoder.H264)
      setAudioEncoder(MediaRecorder.AudioEncoder.AAC)
      setVideoSize(width, height)
      setVideoFrameRate(30)
      setVideoEncodingBitRate(8_000_000)
      setOrientationHint(0)
      prepare()
    }
  }
 
  private fun createOutputFile(): String {
    val sd = File(getExternalFilesDir(null), "RecordVideos")
    if (!sd.exists()) sd.mkdirs()
    val name = "SCR_${SimpleDateFormat("yyyyMMdd_HHmmss",
      Locale.US).format(Date())}.mp4"
    return File(sd, name).absolutePath
  }
 
  private fun buildNotification(): Notification {
    val pi = PendingIntent.getActivity(
      this,0,
      Intent(this, MainActivity::class.java), PendingIntent.FLAG_IMMUTABLE
    )
    return NotificationCompat.Builder(this, App.CHANNEL_ID)
      .setContentTitle("正在錄屏")
      .setSmallIcon(R.drawable.ic_record)
      .setContentIntent(pi)
      .setOngoing(true)
      .build()
  }
 
  override fun onDestroy() {
    super.onDestroy()
    recorder.stop()
    recorder.reset()
    virtualDisplay?.release()
    projection?.stop()
    // 通知系統(tǒng)圖庫更新文件
    sendBroadcast(Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE).apply {
      data = android.net.Uri.fromFile(File(outputFile))
    })
  }
 
  override fun onBind(intent: Intent?) = null
}
 
// =======================================================
// 文件：res/drawable/ic_record.xml
// 描述：錄制狀態(tài)圖標（示例可用系統(tǒng)資源）
// =======================================================
<vector xmlns:android="http://schemas.android.com/apk/res/android"
  android:width="24dp" android:height="24dp" android:viewportWidth="24"
  android:viewportHeight="24">
  <path
      android:fillColor="#F44336"
      android:pathData="M12,3C7.03,3 3,7.03 3,12s4.03,9 9,9 9,-4.03 9,-9S16.97,3 12,3zM12,19c-3.86,0 -7,-3.14 -7,-7s3.14,-7 7,-7 7,3.14 7,7 -3.14,7 -7,7z"/>
  <circle
      android:fillColor="#F44336"
      android:cx="12" android:cy="12" android:r="5"/>
</vector>