Android使用AudioRecord录音，手机息屏一分钟后录音采样值全为0？

Android使用AudioRecord录音，手机息屏一分钟后录音采样值全为0。
部分代码如下：

try {
            OutputStream os = new FileOutputStream(file);
            BufferedOutputStream bos = new BufferedOutputStream(os);
            DataOutputStream dos = new DataOutputStream(bos);
            // Create a new AudioRecord object to record the audio.
            mRecordBufferSize = AudioRecord.getMinBufferSize(mSampleRateInHz, channelConfiguration, audioEncoding) * 2;

            //录音类
            AudioRecord audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, mSampleRateInHz, channelConfiguration, audioEncoding, mRecordBufferSize);
            short[] buffer = new short[mRecordBufferSize];
            audioRecord.startRecording();

            mStopRecording = false;
            /*
            对录音数据保存到本地并添加到缓存数组中
            */
            while (mStartRecording) {
                    short bufferx;
                    int bufferReadResult = audioRecord.read(buffer, 0, mRecordBufferSize);
                    for (int i = 0; i < bufferReadResult; i++) {
                            bufferx = Short.reverseBytes(buffer[i]);
                            dos.writeShort(bufferx);
                    }
                    writeBuffer(buffer);
            }
            //停止录音
            audioRecord.stop();
            dos.close();
            bos.close();
            os.close();

息屏1分钟（很准确的1分钟）后bufferx全为0，唤醒屏幕后又能正常录音。
如何解决这个问题？项目需求息屏时也能完全正常录音。

解决了吗