Android音频开发（3）：使用AudioRecord实现录音

Android 音频开发 目录

1. Android音频开发（1）：音频相关知识
2. Android音频开发（2）：使用AudioRecord录制pcm格式音频
3. Android音频开发（3）：使用AudioRecord实现录音的暂停和恢复
4. Android音频开发（4）：PCM转WAV格式音频
5. Android音频开发（5）：Mp3的录制 - 编译Lame源码
6. Android音频开发（6）：Mp3的录制 - 使用Lame实时录制MP3格式音频

项目地址

https://github.com/zhaolewei/ZlwAudioRecorder

上一篇主要写了AudioRecord实现音频录制的开始和停止，AudioRecord并没有暂停和恢复播放功能的API,所以需要手动实现

一、解决办法

思路很简单，现在可以实现音频的文件录制和停止，并生成pcm文件，那么暂停时将这次文件先保存下来，恢复播放后开始新一轮的录制，那么最后会生成多个pcm音频，再将这些pcm文件进行合并，这样就实现了暂停/恢复的功能了。

二、实现

• 实现的重点在于如何控制录音的状态

/**
 * @author zhaolewei on 2018/7/10.
 */
public class RecordHelper {
    private volatile RecordState state = RecordState.IDLE;
    private AudioRecordThread audioRecordThread;

    private File recordFile = null;
    private File tmpFile = null;
    private List<File> files = new ArrayList<>();

    public void start(String filePath, RecordConfig config) {
        this.currentConfig = config;
        if (state != RecordState.IDLE) {
            Logger.e(TAG, "状态异常当前状态： %s", state.name());
            return;
        }
        recordFile = new File(filePath);
        String tempFilePath = getTempFilePath();
        Logger.i(TAG, "tmpPCM File: %s", tempFilePath);
        tmpFile = new File(tempFilePath);
        audioRecordThread = new AudioRecordThread();
        audioRecordThread.start();
    }

    public void stop() {
        if (state == RecordState.IDLE) {
            Logger.e(TAG, "状态异常当前状态： %s", state.name());
            return;
        }

        //若在暂停中直接停止，则直接合并文件即可
        if (state == RecordState.PAUSE) {
            makeFile();
            state = RecordState.IDLE;
        } else {
            state = RecordState.STOP;
        }
    }

    public void pause() {
        if (state != RecordState.RECORDING) {
            Logger.e(TAG, "状态异常当前状态： %s", state.name());
            return;
        }
        state = RecordState.PAUSE;
    }

    public void resume() {
        if (state != RecordState.PAUSE) {
            Logger.e(TAG, "状态异常当前状态： %s", state.name());
            return;
        }
        String tempFilePath = getTempFilePath();
        Logger.i(TAG, "tmpPCM File: %s", tempFilePath);
        tmpFile = new File(tempFilePath);
        audioRecordThread = new AudioRecordThread();
        audioRecordThread.start();
    }

    private class AudioRecordThread extends Thread {
        private AudioRecord audioRecord;
        private int bufferSize;

        AudioRecordThread() {
            bufferSize = AudioRecord.getMinBufferSize(currentConfig.getFrequency(),
                    currentConfig.getChannel(), currentConfig.getEncoding()) * RECORD_AUDIO_BUFFER_TIMES;
            audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, currentConfig.getFrequency(),
                    currentConfig.getChannel(), currentConfig.getEncoding(), bufferSize);
        }

        @Override
        public void run() {
            super.run();
            state = RecordState.RECORDING;
            notifyState();
            Logger.d(TAG, "开始录制");
            FileOutputStream fos = null;
            try {
                fos = new FileOutputStream(tmpFile);
                audioRecord.startRecording();
                byte[] byteBuffer = new byte[bufferSize];

                while (state == RecordState.RECORDING) {
                        int end = audioRecord.read(byteBuffer, 0, byteBuffer.length);
                    fos.write(byteBuffer, 0, end);
                    fos.flush();
                }
                audioRecord.stop();
                //1. 将本次录音的文件暂存下来，用于合并
                files.add(tmpFile);
                //2. 再此判断终止循环的状态是暂停还是停止，并做相应处理
                if (state == RecordState.STOP) {
                    makeFile();
                } else {
                    Logger.i(TAG, "暂停！");
                }
            } catch (Exception e) {
                Logger.e(e, TAG, e.getMessage());
            } finally {
                try {
                    if (fos != null) {
                        fos.close();
                    }
                } catch (IOException e) {
                    Logger.e(e, TAG, e.getMessage());
                }
            }
            if (state != RecordState.PAUSE) {
                state = RecordState.IDLE;
                notifyState();
                Logger.d(TAG, "录音结束");
            }
        }
    }

    private void makeFile() {
        //合并文件
        boolean mergeSuccess = mergePcmFiles(recordFile, files);

        //TODO:转换wav
        Logger.i(TAG, "录音完成！ path: %s ； 大小：%s", recordFile.getAbsoluteFile(), recordFile.length());
    }

    /**
     * 合并Pcm文件
     *
     * @param recordFile 输出文件
     * @param files      多个文件源
     * @return 是否成功
     */
    private boolean mergePcmFiles(File recordFile, List<File> files) {
        if (recordFile == null || files == null || files.size() <= 0) {
            return false;
        }

        FileOutputStream fos = null;
        BufferedOutputStream outputStream = null;
        byte[] buffer = new byte[1024];
        try {
            fos = new FileOutputStream(recordFile);
            outputStream = new BufferedOutputStream(fos);

            for (int i = 0; i < files.size(); i++) {
                BufferedInputStream inputStream = new BufferedInputStream(new FileInputStream(files.get(i)));
                int readCount;
                while ((readCount = inputStream.read(buffer)) > 0) {
                    outputStream.write(buffer, 0, readCount);
                }
                inputStream.close();
            }
        } catch (Exception e) {
            Logger.e(e, TAG, e.getMessage());
            return false;
        } finally {
            try {
                if (fos != null) {
                    fos.close();
                }
                if (outputStream != null) {
                    outputStream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        //3. 合并后记得删除缓存文件并清除list
        for (int i = 0; i < files.size(); i++) {
            files.get(i).delete();
        }
        files.clear();
        return true;
    }

}

其他

• 在此后如若需要添加录音状态回调，记得使用Handler做好线程切换。