dependencies {
 implementation fileTree(dir: 'libs', include: ['*.jar'])
 implementation"org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
 implementation 'androidx.appcompat:appcompat:1.1.0'
 implementation 'androidx.core:core-ktx:1.0.2'
 implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
 testImplementation 'junit:junit:4.12'
 androidTestImplementation 'androidx.test.ext:junit:1.1.1'
 androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
 api 'com.blankj:utilcode:1.24.4'
}
repositories {
 mavenCentral()
}

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

package com.ufi.pdioms.ztkotlin
 
 
import android.content.Intent
import android.content.res.AssetFileDescriptor
import android.media.MediaPlayer
import android.os.Build
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import android.widget.Toast
import com.blankj.utilcode.util.PathUtils
import kotlinx.android.synthetic.main.activity_main.*
 
class MainActivity : AppCompatActivity() {
 // https://github.com/fanqilongmoli/AndroidScreenRecord
 private var screenRecordHelper: ScreenRecordHelper? = null
 private val afdd:AssetFileDescriptor by lazy { assets.openFd("test.aac") }
 
 override fun onCreate(savedInstanceState: Bundle?) {
  super.onCreate(savedInstanceState)
  setContentView(R.layout.activity_main)
 
  btnStart.setOnClickListener {
   if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
    if (screenRecordHelper == null) {
     screenRecordHelper = ScreenRecordHelper(this, object : ScreenRecordHelper.OnVideoRecordListener {
      override fun onBeforeRecord() {
      }
 
      override fun onStartRecord() {
       play()
      }
 
      override fun onCancelRecord() {
       releasePlayer()
      }
 
      override fun onEndRecord() {
       releasePlayer()
      }
 
     }, PathUtils.getExternalStoragePath() + "/fanqilong")
    }
    screenRecordHelper?.apply {
     if (!isRecording) {
      // 如果你想錄制音頻（一定會有環境音量），你可以打開下面這個限制,并且使用不帶參數的 stopRecord()
//      recordAudio = true
      startRecord()
     }
    }
   } else {
    Toast.makeText(this@MainActivity.applicationContext, "sorry,your phone does not support recording screen", Toast.LENGTH_LONG).show()
   }
  }
 
  btnStop.setOnClickListener {
   if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
    screenRecordHelper?.apply {
     if (isRecording) {
      if (mediaPlayer != null) {
       // 如果選擇帶參數的 stop 方法，則錄制音頻無效
       stopRecord(mediaPlayer!!.duration.toLong(), 15 * 1000, afdd)
      } else {
       stopRecord()
      }
     }
    }
   }
  }
 }
 
 private fun play() {
  mediaPlayer = MediaPlayer()
  try {
   mediaPlayer?.apply {
    this.reset()
    this.setDataSource(afdd.fileDescriptor, afdd.startOffset, afdd.length)
    this.isLooping = true
    this.prepare()
    this.start()
   }
  } catch (e: Exception) {
   Log.d("fanqilong", "播放音樂失敗")
  } finally {
 
  }
 }
 
 // 音頻播放
 private var mediaPlayer: MediaPlayer? = null
 
 private fun releasePlayer() {
  mediaPlayer?.apply {
   stop()
   release()
  }
  mediaPlayer = null
 }
 
 override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
  super.onActivityResult(requestCode, resultCode, data)
  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP && data != null) {
   screenRecordHelper?.onActivityResult(requestCode, resultCode, data)
  }
 }
 
 override fun onDestroy() {
  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
   screenRecordHelper?.clearAll()
  }
  afdd.close()
  super.onDestroy()
 }
}

package com.ufi.pdioms.ztkotlin
 
import android.app.Activity
import android.content.Context
import android.content.Intent
import android.content.pm.PackageManager
import android.content.res.AssetFileDescriptor
import android.hardware.display.DisplayManager
import android.hardware.display.VirtualDisplay
import android.media.*
import android.media.projection.MediaProjection
import android.media.projection.MediaProjectionManager
import android.net.Uri
import android.os.Build
import android.os.Environment
import android.os.Handler
import android.util.DisplayMetrics
import android.util.Log
import android.widget.Toast
import androidx.annotation.RequiresApi
import com.blankj.utilcode.constant.PermissionConstants
import com.blankj.utilcode.util.PermissionUtils
import java.io.File
import java.lang.Exception
import java.nio.ByteBuffer
 
@RequiresApi(Build.VERSION_CODES.LOLLIPOP)
class ScreenRecordHelper @JvmOverloads constructor(
 private var activity: Activity,
 private val listener: OnVideoRecordListener?,
 private var savePath: String = Environment.getExternalStorageDirectory().absolutePath + File.separator
   + "DCIM" + File.separator + "Camera",
 private val saveName: String = "record_${System.currentTimeMillis()}"
) {
 
 private val mediaProjectionManager by lazy { activity.getSystemService(Context.MEDIA_PROJECTION_SERVICE) as? MediaProjectionManager }
 private var mediaRecorder: MediaRecorder? = null
 private var mediaProjection: MediaProjection? = null
 private var virtualDisplay: VirtualDisplay? = null
 private val displayMetrics by lazy { DisplayMetrics() }
 private var saveFile: File? = null
 var isRecording = false
 var recordAudio = false
 
 init {
  activity.windowManager.defaultDisplay.getMetrics(displayMetrics)
 }
 
 companion object {
  private const val VIDEO_FRAME_RATE = 30
  private const val REQUEST_CODE = 1024
  private const val TAG = "ScreenRecordHelper"
 }
 
 fun startRecord() {
  if (mediaProjectionManager == null) {
   Log.d(TAG, "mediaProjectionManager == null，當前手機暫不支持錄屏")
   showToast(R.string.phone_not_support_screen_record)
   return
  }
 
  PermissionUtils.permission(PermissionConstants.STORAGE, PermissionConstants.MICROPHONE)
   .callback(object : PermissionUtils.SimpleCallback {
    override fun onGranted() {
     mediaProjectionManager?.apply {
      listener?.onBeforeRecord()
      val intent = this.createScreenCaptureIntent()
      if (activity.packageManager.resolveActivity(
        intent,
        PackageManager.MATCH_DEFAULT_ONLY
       ) != null
      ) {
       activity.startActivityForResult(intent, REQUEST_CODE)
      } else {
       showToast(R.string.phone_not_support_screen_record)
      }
     }
    }
 
    override fun onDenied() {
     showToast(R.string.permission_denied)
    }
 
   }).request()
 }
 
 @RequiresApi(Build.VERSION_CODES.N)
 fun resume() {
  mediaRecorder?.resume()
 }
 
 @RequiresApi(Build.VERSION_CODES.N)
 fun pause() {
  mediaRecorder?.pause()
 }
 
 fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent) {
  if (requestCode == REQUEST_CODE) {
   if (resultCode == Activity.RESULT_OK) {
    mediaProjection = mediaProjectionManager!!.getMediaProjection(resultCode, data)
 
    // 部分手機錄制視頻的時候 會出現彈框
    Handler().postDelayed({
     if (initRecorder()) {
      isRecording = true
      mediaRecorder?.start()
      listener?.onStartRecord()
     } else {
      showToast(R.string.phone_not_support_screen_record)
     }
    }, 150)
   } else {
    showToast(R.string.phone_not_support_screen_record)
   }
  }
 }
 
 fun cancelRecord(){
  stopRecord()
  saveFile?.delete()
  saveFile = null
  listener?.onCancelRecord()
 }
 
 
 fun stopRecord(videoDuration: Long = 0, audioDuration: Long = 0, afdd: AssetFileDescriptor? = null){
  stop()
  if (audioDuration != 0L && afdd != null) {
   syntheticAudio(videoDuration, audioDuration, afdd)
  } else {
   // saveFile
   if (saveFile != null) {
    val newFile = File(savePath, "$saveName.mp4")
    // 錄制結束后修改后綴為 mp4
    saveFile!!.renameTo(newFile)
    refreshVideo(newFile)
   }
   saveFile = null
  }
 }
 
 
 private fun refreshVideo(newFile: File) {
  Log.d(TAG, "screen record end,file length:${newFile.length()}.")
  if (newFile.length() > 5000) {
   val intent = Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE)
   intent.data = Uri.fromFile(newFile)
   activity.sendBroadcast(intent)
   Log.e("TAG","refreshVideo: "+savePath)
   showToast(R.string.save_to_album_success)
  } else {
   newFile.delete()
   showToast(R.string.phone_not_support_screen_record)
   Log.d(TAG, activity.getString(R.string.record_faild))
  }
 }
 
 private fun stop() {
  if (isRecording) {
   isRecording = false
   try {
    mediaRecorder?.apply {
     setOnErrorListener(null)
     setOnInfoListener(null)
     setPreviewDisplay(null)
     stop()
     Log.d(TAG, "stop success")
    }
   } catch (e: Exception) {
    Log.e(TAG, "stopRecorder() error！${e.message}")
   } finally {
    mediaRecorder?.reset()
    virtualDisplay?.release()
    mediaProjection?.stop()
    listener?.onEndRecord()
   }
 
 
  }
 }
 
 private fun initRecorder(): Boolean {
  var result = true
  val f = File(savePath)
  if (!f.exists()) {
   f.mkdir()
  }
  saveFile = File(savePath, "$saveName.tmp")
  saveFile?.apply {
   if (exists()) {
    delete()
   }
  }
  mediaRecorder = MediaRecorder()
  val width = Math.min(displayMetrics.widthPixels, 1080)
  val height = Math.min(displayMetrics.heightPixels, 1920)
  mediaRecorder?.apply {
   if (recordAudio) {
    setAudioSource(MediaRecorder.AudioSource.MIC)
   }
   setVideoSource(MediaRecorder.VideoSource.SURFACE)
   setOutputFormat(MediaRecorder.OutputFormat.MPEG_4)
   setVideoEncoder(MediaRecorder.VideoEncoder.H264)
   if (recordAudio) {
    setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB)
   }
   setOutputFile(saveFile!!.absolutePath)
   setVideoSize(width, height)
   setVideoEncodingBitRate(8388608)
   setVideoFrameRate(VIDEO_FRAME_RATE)
 
   try {
 
    prepare()
    virtualDisplay = mediaProjection?.createVirtualDisplay(
     "MainScreen", width, height, displayMetrics.densityDpi,
     DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR, surface, null, null
    )
    Log.d(TAG, "initRecorder 成功")
   } catch (e: Exception) {
    Log.e(TAG, "IllegalStateException preparing MediaRecorder: ${e.message}")
    e.printStackTrace()
    result = false
   }
  }
 
  return result
 }
 
 
 private fun showToast(resId: Int) {
  Toast.makeText(activity.applicationContext, activity.applicationContext.getString(resId), Toast.LENGTH_SHORT)
   .show()
 }
 
 fun clearAll() {
  mediaRecorder?.release()
  mediaRecorder = null
  virtualDisplay?.release()
  virtualDisplay = null
  mediaProjection?.stop()
  mediaProjection = null
 }
 
 /**
  * https://stackoverflow.com/questions/31572067/android-how-to-mux-audio-file-and-video-file
  */
 private fun syntheticAudio(audioDuration: Long, videoDuration: Long, afdd: AssetFileDescriptor) {
  Log.d(TAG, "start syntheticAudio")
  val newFile = File(savePath, "$saveName.mp4")
  if (newFile.exists()) {
   newFile.delete()
  }
  try {
   newFile.createNewFile()
   val videoExtractor = MediaExtractor()
   videoExtractor.setDataSource(saveFile!!.absolutePath)
   val audioExtractor = MediaExtractor()
   afdd.apply {
    audioExtractor.setDataSource(fileDescriptor, startOffset, length * videoDuration / audioDuration)
   }
   val muxer = MediaMuxer(newFile.absolutePath, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4)
   videoExtractor.selectTrack(0)
   val videoFormat = videoExtractor.getTrackFormat(0)
   val videoTrack = muxer.addTrack(videoFormat)
 
   audioExtractor.selectTrack(0)
   val audioFormat = audioExtractor.getTrackFormat(0)
   val audioTrack = muxer.addTrack(audioFormat)
 
   var sawEOS = false
   var frameCount = 0
   val offset = 100
   val sampleSize = 1000 * 1024
   val videoBuf = ByteBuffer.allocate(sampleSize)
   val audioBuf = ByteBuffer.allocate(sampleSize)
   val videoBufferInfo = MediaCodec.BufferInfo()
   val audioBufferInfo = MediaCodec.BufferInfo()
 
   videoExtractor.seekTo(0, MediaExtractor.SEEK_TO_CLOSEST_SYNC)
   audioExtractor.seekTo(0, MediaExtractor.SEEK_TO_CLOSEST_SYNC)
 
   muxer.start()
 
   // 每秒多少幀
   // 實測 OPPO R9em 垃圾手機，拿出來的沒有 MediaFormat.KEY_FRAME_RATE
   val frameRate = if (videoFormat.containsKey(MediaFormat.KEY_FRAME_RATE)) {
    videoFormat.getInteger(MediaFormat.KEY_FRAME_RATE)
   } else {
    31
   }
   // 得出平均每一幀間隔多少微妙
   val videoSampleTime = 1000 * 1000 / frameRate
   while (!sawEOS) {
    videoBufferInfo.offset = offset
    videoBufferInfo.size = videoExtractor.readSampleData(videoBuf, offset)
    if (videoBufferInfo.size < 0) {
     sawEOS = true
     videoBufferInfo.size = 0
    } else {
     videoBufferInfo.presentationTimeUs += videoSampleTime
     videoBufferInfo.flags = videoExtractor.sampleFlags
     muxer.writeSampleData(videoTrack, videoBuf, videoBufferInfo)
     videoExtractor.advance()
     frameCount++
    }
   }
   var sawEOS2 = false
   var frameCount2 = 0
   while (!sawEOS2) {
    frameCount2++
    audioBufferInfo.offset = offset
    audioBufferInfo.size = audioExtractor.readSampleData(audioBuf, offset)
 
    if (audioBufferInfo.size < 0) {
     sawEOS2 = true
     audioBufferInfo.size = 0
    } else {
     audioBufferInfo.presentationTimeUs = audioExtractor.sampleTime
     audioBufferInfo.flags = audioExtractor.sampleFlags
     muxer.writeSampleData(audioTrack, audioBuf, audioBufferInfo)
     audioExtractor.advance()
    }
   }
   muxer.stop()
   muxer.release()
   videoExtractor.release()
   audioExtractor.release()
 
   // 刪除無聲視頻文件
   saveFile?.delete()
  } catch (e: Exception) {
   Log.e(TAG, "Mixer Error:${e.message}")
   // 視頻添加音頻合成失敗，直接保存視頻
   saveFile?.renameTo(newFile)
 
  } finally {
   afdd.close()
   Handler().post {
    refreshVideo(newFile)
    saveFile = null
   }
  }
 }
 
 
 interface OnVideoRecordListener {
 
  /**
   * 錄制開始時隱藏不必要的UI
   */
  fun onBeforeRecord()
 
  /**
   * 開始錄制
   */
  fun onStartRecord()
 
  /**
   * 取消錄制
   */
  fun onCancelRecord()
 
  /**
   * 結束錄制
   */
  fun onEndRecord()
 }
}

<?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">
 
 <Button android:id="@+id/btnStart"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:textAllCaps="false"
  android:text="start"/>
 
 <Button android:id="@+id/btnStop"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:textAllCaps="false"
  android:text="stop"/>
 
 
</LinearLayout>