Android后台屏幕录制代码

A：以下是一个基本的Android后台屏幕录制代码：

public class ScreenRecorder extends Thread {

    private static final int VIDEO_FRAME_RATE = 30;
    private static final int VIDEO_BITRATE = 1000000;
    private static final int VIDEO_I_FRAME_INTERVAL = 10;
    private static final int VIDEO_WIDTH = 720;
    private static final int VIDEO_HEIGHT = 1280;

    private MediaRecorder mMediaRecorder;
    private Surface mSurface;
    private boolean mIsRecording;

    public ScreenRecorder(Surface surface) {
        mSurface = surface;
    }

    @Override
    public void run() {
        try {
            mMediaRecorder = new MediaRecorder();
            mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.Surface);
            mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
            mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
            mMediaRecorder.setVideoSize(VIDEO_WIDTH, VIDEO_HEIGHT);
            mMediaRecorder.setVideoFrameRate(VIDEO_FRAME_RATE);
            mMediaRecorder.setVideoEncodingBitRate(VIDEO_BITRATE);
            mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
            mMediaRecorder.setVideoEncodingBitRate(VIDEO_BITRATE);
            mMediaRecorder.setVideoFrameRate(VIDEO_FRAME_RATE);
            mMediaRecorder.setVideoIFrameInterval(VIDEO_I_FRAME_INTERVAL);
            mMediaRecorder.setOutputFile(getOutputFilePath());

            mMediaRecorder.prepare();
            mMediaRecorder.setInputSurface(mSurface);
            mMediaRecorder.start();

            mIsRecording = true;
        } catch (Exception e) {
            Log.e("Screen Recorder", "Screen recording failed: " + e.getMessage());
        }
    }

    public void stopRecording() {
        if (mIsRecording) {
            mMediaRecorder.stop();
            mMediaRecorder.release();
            mIsRecording = false;
        }
    }

    private String getOutputFilePath() {
        String directory = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MOVIES).getAbsolutePath();
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        String currentTimeStamp = dateFormat.format(new Date());
        String filename = "Screen Recording - " + currentTimeStamp + ".mp4";
        return directory + "/" + filename;
    }
}

首先，我们定义了一些常量，例如视频帧速率、视频编码器、视频宽度和高度等。然后，我们创建了一个`MediaRecorder`对象，并设置了视频源、输出格式、视频编码器、大小、帧速率、码率、I帧间隔和输出文件路径等参数。最后，我们调用`prepare`方法来准备录制，并调用`start`方法开始录制。

要停止录制，我们可以调用`stop`方法和`release`方法来停止和释放`MediaRecorder`对象。

请注意，由于Android限制了在后台录制屏幕的能力，因此您需要在应用程序前台或设备上运行代码。您还需要在manifest文件中声明RECORD_AUDIO和WRITE_EXTERNAL_STORAGE权限。