android - AudioRecord 总是创建失败

Question

我在使用 AudioRecord for Android 时遇到了问题。我已经尽可能多地在网上找到有关它的信息，但我似乎无法进行良好的初始化。

我创建 AudioRecord 对象的代码是这样的:

    int bufferSize = AudioRecord.getMinBufferSize(44100, AudioFormat.CHANNEL_IN_MONO,
            AudioFormat.ENCODING_PCM_16BIT);
    if (bufferSize < 4096)
        bufferSize = 4096;

    mBuffer = new short[bufferSize];
    audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, 44100, AudioFormat.CHANNEL_IN_MONO,
            AudioFormat.ENCODING_PCM_16BIT, bufferSize);

并且我已经获得了正确的许可:

但每当我运行该应用程序时，它都会显示此错误:

08-12 11:56:05.669: E/AudioRecord(10689): Could not get audio inputfor record source 1

08-12 11:56:05.669: E/AudioRecord-JNI(10689):Error creating AudioRecord instance: initialization check failed.

08-12 11:56:05.669: E/AudioRecord-Java(10689): [android.media.AudioRecord ] Error code -20 when initializing nativeAudioRecord object.

---

Answer 1

所以这是在 android 中录制音频文件所必须执行的操作。首先，您必须向 Androidmanifest.xml 文件添加一些权限。应用程序需要有写入外部存储的权限Android的录音

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

接下来你必须导入所需的类和函数

import android.app.Activity;
import android.widget.LinearLayout;
import android.os.Bundle;
import android.os.Environment;
import android.view.ViewGroup;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;
import android.content.Context;
import android.util.Log;
import android.media.MediaRecorder;
import android.media.MediaPlayer;

import java.io.IOException;

创建 Android.media.MediaRecorder 的实例。

private void startRecording() {

 mRecorder = new MediaRecorder();

接下来，您必须设置音频输入源，在大多数情况下，您会使用 Android 设备的 MIC 为应用程序提供音频输入，以便在 Android 中录制音频文件。在这种情况下，您必须将音频源设置为:MediaRecorder.AudioSource.MIC

mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);

接下来，您必须为记录器文件定义输出格式。 Android 支持多种音频格式。为此，您必须使用 MediaRecorder.SetOutputFormat();功能。

 mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);

现在您必须命名一个文件，该文件将以您指定的格式保存您的录音。为此，您必须使用 MediaRecorder.SetOutputfile() 函数。

mRecorder.setOutputFile(mFileName);

现在使用 MediaRecorder.setAudioEncoder() 函数设置音频编码器。

mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);

为录制音频输入调用 MediaRecorder.prepare() 准备您的应用程序

 mPlayer.prepare();
            mPlayer.start();
        } catch (IOException e) {
            Log.e(LOG_TAG, "prepare() failed");
        }
    }

现在一切都已准备就绪，您所要做的就是启动音频捕获过程。为此你必须这样做:MediaRecorder.start();

class RecordButton extends Button {
        boolean mStartRecording = true;

        OnClickListener clicker = new OnClickListener() {
            public void onClick(View v) {
                onRecord(mStartRecording);
                if (mStartRecording) {
                    setText("Stop recording");
                } else {
                    setText("Start recording");
                }
                mStartRecording = !mStartRecording;
            }
        };

        public RecordButton(Context ctx) {
            super(ctx);
            setText("Start recording");
            setOnClickListener(clicker);
        }
    }

要停止录制，请调用 MediaRecorder.stop()最后，当您完成录制后，您必须通过调用 MediaRecorder.release() 释放资源

mPlayer.release();

下面是一个录制音频然后回放的应用程序示例。

package com.android.audiorecordtest;

import android.app.Activity;
import android.widget.LinearLayout;
import android.os.Bundle;
import android.os.Environment;
import android.view.ViewGroup;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;
import android.content.Context;
import android.util.Log;
import android.media.MediaRecorder;
import android.media.MediaPlayer;

import java.io.IOException;

public class AudioRecordTest extends Activity
{
    private static final String LOG_TAG = "AudioRecordTest";
    private static String mFileName = null;

    private RecordButton mRecordButton = null;
    private MediaRecorder mRecorder = null;

    private PlayButton   mPlayButton = null;
    private MediaPlayer   mPlayer = null;

    private void onRecord(boolean start) {
        if (start) {
            startRecording();
        } else {
            stopRecording();
        }
    }

    private void onPlay(boolean start) {
        if (start) {
            startPlaying();
        } else {
            stopPlaying();
        }
    }

    private void startPlaying() {
        mPlayer = new MediaPlayer();
        try {
            mPlayer.setDataSource(mFileName);
            mPlayer.prepare();
            mPlayer.start();
        } catch (IOException e) {
            Log.e(LOG_TAG, "prepare() failed");
        }
    }

    private void stopPlaying() {
        mPlayer.release();
        mPlayer = null;
    }

    private void startRecording() {
        mRecorder = new MediaRecorder();
        mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        mRecorder.setOutputFile(mFileName);
        mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);

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

        mRecorder.start();
    }

    private void stopRecording() {
        mRecorder.stop();
        mRecorder.release();
        mRecorder = null;
    }

    class RecordButton extends Button {
        boolean mStartRecording = true;

        OnClickListener clicker = new OnClickListener() {
            public void onClick(View v) {
                onRecord(mStartRecording);
                if (mStartRecording) {
                    setText("Stop recording");
                } else {
                    setText("Start recording");
                }
                mStartRecording = !mStartRecording;
            }
        };

        public RecordButton(Context ctx) {
            super(ctx);
            setText("Start recording");
            setOnClickListener(clicker);
        }
    }

    class PlayButton extends Button {
        boolean mStartPlaying = true;

        OnClickListener clicker = new OnClickListener() {
            public void onClick(View v) {
                onPlay(mStartPlaying);
                if (mStartPlaying) {
                    setText("Stop playing");
                } else {
                    setText("Start playing");
                }
                mStartPlaying = !mStartPlaying;
            }
        };

        public PlayButton(Context ctx) {
            super(ctx);
            setText("Start playing");
            setOnClickListener(clicker);
        }
    }

    public AudioRecordTest() {
        mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
        mFileName += "/audiorecordtest.3gp";
    }

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        LinearLayout ll = new LinearLayout(this);
        mRecordButton = new RecordButton(this);
        ll.addView(mRecordButton,
            new LinearLayout.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT,
                0));
        mPlayButton = new PlayButton(this);
        ll.addView(mPlayButton,
            new LinearLayout.LayoutParams(
                ViewGroup.LayoutParams.WRAP_CONTENT,
                ViewGroup.LayoutParams.WRAP_CONTENT,
                0));
        setContentView(ll);
    }

    @Override
    public void onPause() {
        super.onPause();
        if (mRecorder != null) {
            mRecorder.release();
            mRecorder = null;
        }

        if (mPlayer != null) {
            mPlayer.release();
            mPlayer = null;
        }
    }
}

或使用 this很棒的教程