这是来自StackOverflow上的一位网友的答案：

MediaRecorder recorder = new MediaRecorder();
recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
recorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
recorder.setOutputFile(Environment.getExternalStorageDirectory()
.getAbsolutePath() + “/myrecording.mp3”);
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
recorder.prepare();
recorder.start();