Android 如何使用AudioRecord录制音频并转换成wav格式

使用AudioRecord录制音频并转换成wav格式，需要进行以下步骤：

1. 设置录音参数：采样率、音频通道、编码格式等
2. 创建一个AudioRecord对象
3. 开始录制音频，将音频数据写入到一个缓存区
4. 录制完成后，停止录音并释放AudioRecord对象
5. 将缓存区中的音频数据写入到一个wav文件中

下面是一个简单的示例代码，演示如何使用AudioRecord录制音频并将其转换成wav格式：

// 设置录音参数
int sampleRateInHz = 44100;
int channelConfig = AudioFormat.CHANNEL_IN_MONO;
int audioFormat = AudioFormat.ENCODING_PCM_16BIT;
int bufferSizeInBytes = AudioRecord.getMinBufferSize(sampleRateInHz, channelConfig, audioFormat);

// 创建AudioRecord对象
AudioRecord audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, sampleRateInHz, channelConfig, audioFormat, bufferSizeInBytes);

// 开始录音
audioRecord.startRecording();

// 定义缓存区
byte[] buffer = new byte[bufferSizeInBytes];

// 定义输出文件
String outputFileName = "output.wav";
File outputFile = new File(Environment.getExternalStorageDirectory(), outputFileName);

// 定义输出流
FileOutputStream outputStream = new FileOutputStream(outputFile);

// 写入wav文件头
WaveHeader waveHeader = new WaveHeader(sampleRateInHz, channelConfig, audioFormat, bufferSizeInBytes);
waveHeader.write(outputStream);

// 写入音频数据
int readSize;
while ((readSize = audioRecord.read(buffer, 0, bufferSizeInBytes)) != AudioRecord.ERROR_INVALID_OPERATION) {
    outputStream.write(buffer, 0, readSize);
}

// 停止录音并释放资源
audioRecord.stop();
audioRecord.release();

// 关闭输出流
outputStream.close();

在上述代码中，我们使用了一个自定义的WaveHeader类，用于生成wav文件头信息。该类的实现可以参考下面的示例代码：

public class WaveHeader {

    private int sampleRate;
    private int channelCount;
    private int audioFormat;
    private int audioDataLength;

    public WaveHeader(int sampleRate, int channelCount, int audioFormat, int audioDataLength) {
        this.sampleRate = sampleRate;
        this.channelCount = channelCount;
        this.audioFormat = audioFormat;
        this.audioDataLength = audioDataLength;
    }

    public void write(OutputStream outputStream) throws IOException {
        outputStream.write("RIFF".getBytes());
        outputStream.write(intToByteArray(36 + audioDataLength), 0, 4);
        outputStream.write("WAVE".getBytes());
        outputStream.write("fmt ".getBytes());
        outputStream.write(intToByteArray(16), 0, 4);
        outputStream.write(shortToByteArray((short) 1), 0, 2);
        outputStream.write(shortToByteArray((short) channelCount), 0, 2);
        outputStream.write(intToByteArray(sampleRate), 0, 4);
        outputStream.write(intToByteArray(sampleRate * channelCount * audioFormat / 8), 0, 4);
        outputStream.write(shortToByteArray((short) (channelCount * audioFormat / 8)), 0, 2);
        outputStream.write(shortToByteArray((short) audioFormat), 0, 2);
        outputStream.write("data".getBytes());
        outputStream.write(intToByteArray(audioDataLength), 0, 4);
    }

    private byte[] intToByteArray(int value) {
        byte[] byteArray = new byte[4];
        byteArray[0] = (byte) (value & 0xff);
        byteArray[1] = (byte) ((value >> 8) & 0xff);
        byteArray[2] = (byte) ((value >> 16) & 0xff);
        byteArray[3] = (byte) ((value >> 24) & 0xff);
        return byteArray;
    }

    private byte[] shortToByteArray(short value) {
        byte[] byteArray = new byte[2];
        byteArray[0] = (byte) (value & 0xff);
        byteArray[1] = (byte) ((value >> 8) & 0xff);
        return byteArray;
    }
}

通过以上代码，我们可以实现将AudioRecord录制的音频转换成wav格式并保存到文件中。需要注意的是，由于Android 6.0及以上版本需要动态获取录音权限，因此在使用前需要先请求录音权限。