为什么我不能在 Kotlin 中创建文件对象？

Question

New to Kotlin. Trying to save an audio recording to storage. I'm currently stuck on trying to use MediaRecord.setOutputFile(filename). However, it is erroring out because of this error:

java.io.FileNotFoundException: /storage/emulated/0/Recording1.mp3: open failed: EPERM (Operation not permitted)

So now I'd like to create a File before setOutputFile is called to try to solve this problem. But for some reason Android Studio keeps underlining the line below saying "Expecting a top level declaration".

File fileval = File.createNewFile("blah.mp3"); //This is the line

The full code:

package com.example.testapp.data

import android.content.Intent;
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle;
import android.widget.Button;
import android.widget.Toast;
import android.media.MediaRecorder;
import android.os.Environment
import android.os.PersistableBundle
import com.example.testapp.R
import android.Manifest
import android.content.Context
import android.content.pm.PackageManager
import android.media.MediaPlayer
import android.os.Build
import android.os.Environment.getDataDirectory
import android.util.Log
import androidx.annotation.RequiresApi
import androidx.appcompat.widget.AppCompatButton
import java.io.File
import java.io.IOException

private const val LOG_TAG = "AudioRecordTest"
private const val REQUEST_RECORD_AUDIO_PERMISSION = 200

File fileval = File.createNewFile("blah.mp3"); //This is the line

public class RecordActivity : AppCompatActivity() {

    private var mr: MediaRecorder? = null
    private var recordbtn: Button? = null
    private var filename: String? = null
    private var state: Boolean = false

    private var recordingStopped: Boolean = false
    private var player: MediaPlayer? = null
    private var playbtn: Button? = null

    // Requesting permission to RECORD_AUDIO
    private var permissionToRecordAccepted = false
    private var permissions: Array<String> = arrayOf(Manifest.permission.RECORD_AUDIO)

    @RequiresApi(Build.VERSION_CODES.M)
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_record)

        requestPermissions(permissions, REQUEST_RECORD_AUDIO_PERMISSION)

        recordbtn = RecordButton(this)
        playbtn = PlayButton(this)

        filename = Environment.getExternalStorageDirectory().getAbsolutePath()
        filename += "/Recording1.mp3"

        mr = MediaRecorder()
        mr?.setAudioSource(MediaRecorder.AudioSource.MIC)
        mr?.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4)
        mr?.setOutputFile(filename)
        mr?.setAudioEncoder(3) //AAC; need to review what the best choice here is.
        mr?.prepare()

    }

//more code...


}

Answer 1

You're using Java syntax, not Kotlin syntax. It's

val fileval: File = File.createNewFile("blah.mp3")

Answer 2

Use below code in the AppCompatActivity()

fileName = "${externalCacheDir!!.absolutePath}/Recording1.3gp"

 mr = MediaRecorder().apply {
            setAudioSource(MediaRecorder.AudioSource.MIC)
            setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP)
            setOutputFile(fileName)
            setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB)

            try {
                prepare()
            } catch (e: IOException) {
                Log.e(LOG_TAG, "prepare() failed")
            }

            start()
        }