AudioRecord是安卓多媒體框架中用于錄制音頻的工具。它支持錄制原始音頻數據，即PCM數據，PCM數據不能被播放器直接播放，需要編碼壓縮成常見音頻格式才能被播放器識別。通常生成PCM文件之后可將PCM文件轉成WAV文件一般的播放器便可直接播放了。

接下來處理AudioRecord操作。

1.初始化AudioRecord

先了解幾個概念：

audioSource：音頻來源
sampleRateInHz：采樣率，以赫茲為單位。目前，只有44100Hz是保證在所有設備上都可以使用的速率(最適合人耳的)，但是其他速率（例如22050、16000和11025）可能在某些設備上可以使用；如果用于語音識別的話根據不同廠商需要采用不同的采樣率
channelConfig：音頻通道的配置
audioFormat：音頻數據的格式
bufferSizeInBytes：在錄制期間寫入音頻數據的緩沖區的總大小（以字節為單位）

初始化操作：

int mBufferSize = AudioRecord.getMinBufferSize(16000, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT)*2;
AudioRecord mAudioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC,16000,AudioFormat.CHANNEL_IN_MONO,//雙聲道AudioFormat.ENCODING_PCM_16BIT,mBufferSize);

?2.開始錄音

 /*** 錄制pcm文件* @param pcmFilePath pcm文件路徑*/public void startRecord(String pcmFilePath) {if (isRecord) {return;}this.mPcmFilePath=pcmFilePath;isRecord = true;RecordThread recordThread = new RecordThread();mExecutorService.execute(recordThread);}class RecordThread implements Runnable {@Overridepublic void run() {mAudioRecord.startRecording();FileOutputStream fos = null;try {Log.i(TAG, "文件地址: " + mPcmFilePath);fos = new FileOutputStream(mPcmFilePath);byte[] bytes = new byte[mBufferSize];while (isRecord) {mAudioRecord.read(bytes, 0, bytes.length);fos.write(bytes, 0, bytes.length);fos.flush();}Log.i(TAG, "停止錄制");mAudioRecord.stop();fos.flush();} catch (IOException e) {e.printStackTrace();} finally {if (fos != null) {try {fos.close();} catch (IOException e) {e.printStackTrace();}}}}}

3.結束錄音

/*** 停止錄制*/public void stopRecord() {isRecord = false;}

4.將錄音生成的pcm文件轉成wav文件

/*** pcm文件轉wav文件* @param pcmFile pcm文件* @param wavFile wav文件*/public void pcm2Wav(File pcmFile, File wavFile) {if (!pcmFile.exists()){throw new RuntimeException(pcmFile.getAbsolutePath()+",there is no pcm file");}mExecutorService.execute(new PcmToWavThread(pcmFile,wavFile));}class PcmToWavThread implements Runnable {File pcmFile;File wavFile;public PcmToWavThread(File pcmFile, File wavFile) {this.pcmFile = pcmFile;this.wavFile = wavFile;}@Overridepublic void run() {if (!wavFile.exists()){try {wavFile.createNewFile();PcmToWavUtil util=new PcmToWavUtil(mSampleRate,mChannel,mFormat);util.pcmToWav(pcmFile.getAbsolutePath(),wavFile.getAbsolutePath());} catch (IOException e) {e.printStackTrace();}}}}

?pcm文成wav文件方法如下：

/*** pcm文件轉wav文件** @param inFilename 源文件路徑* @param outFilename 目標文件路徑*/public void pcmToWav(String inFilename, String outFilename) {FileInputStream in;FileOutputStream out;long totalAudioLen;//總錄音長度long totalDataLen;//總數據長度long longSampleRate = mSampleRate;int channels = mChannel == AudioFormat.CHANNEL_IN_MONO ? 1 : 2;long byteRate = 16 * mSampleRate * channels / 8;byte[] data = new byte[mBufferSize];try {in = new FileInputStream(inFilename);out = new FileOutputStream(outFilename);totalAudioLen = in.getChannel().size();totalDataLen = totalAudioLen + 36;writeWaveFileHeader(out, totalAudioLen, totalDataLen,longSampleRate, channels, byteRate);while (in.read(data) != -1) {out.write(data);out.flush();}Log.e(TAG, "pcmToWav: 停止處理");in.close();out.close();} catch (IOException e) {e.printStackTrace();}}/*** 加入wav文件頭*/private void writeWaveFileHeader(FileOutputStream out, long totalAudioLen,long totalDataLen, long longSampleRate, int channels, long byteRate)throws IOException {byte[] header = new byte[44];// RIFF/WAVE headerheader[0] = 'R';header[1] = 'I';header[2] = 'F';header[3] = 'F';header[4] = (byte) (totalDataLen & 0xff);header[5] = (byte) ((totalDataLen >> 8) & 0xff);header[6] = (byte) ((totalDataLen >> 16) & 0xff);header[7] = (byte) ((totalDataLen >> 24) & 0xff);//WAVEheader[8] = 'W';header[9] = 'A';header[10] = 'V';header[11] = 'E';// 'fmt ' chunkheader[12] = 'f';header[13] = 'm';header[14] = 't';header[15] = ' ';// 4 bytes: size of 'fmt ' chunkheader[16] = 16;header[17] = 0;header[18] = 0;header[19] = 0;// format = 1header[20] = 1;header[21] = 0;header[22] = (byte) channels;header[23] = 0;header[24] = (byte) (longSampleRate & 0xff);header[25] = (byte) ((longSampleRate >> 8) & 0xff);header[26] = (byte) ((longSampleRate >> 16) & 0xff);header[27] = (byte) ((longSampleRate >> 24) & 0xff);header[28] = (byte) (byteRate & 0xff);header[29] = (byte) ((byteRate >> 8) & 0xff);header[30] = (byte) ((byteRate >> 16) & 0xff);header[31] = (byte) ((byteRate >> 24) & 0xff);// block alignheader[32] = (byte) (2 * 16 / 8);header[33] = 0;// bits per sampleheader[34] = 16;header[35] = 0;//dataheader[36] = 'd';header[37] = 'a';header[38] = 't';header[39] = 'a';header[40] = (byte) (totalAudioLen & 0xff);header[41] = (byte) ((totalAudioLen >> 8) & 0xff);header[42] = (byte) ((totalAudioLen >> 16) & 0xff);header[43] = (byte) ((totalAudioLen >> 24) & 0xff);out.write(header, 0, 44);}

5.釋放資源

/*** 釋放資源*/public void release() {if (mAudioRecord != null) {mAudioRecord.release();}if (mExecutorService!=null){mExecutorService.shutdown();}}

至此錄音功能即可實現了，如果想要測試可以直接使用MediaPlayer方法進行錄音播放