如何在安卓Pjsua2视频通话中显示和隐藏视频？

CallOpParam callOpParam = new CallOpParam(true);
callOpParam.setVideoCount(1); // 启用视频
call.makeCall(uri, callOpParam);

public class MyCall extends Call {
    private SurfaceView videoView;

    public MyCall(Account acc, int call_id) {
        super(acc, call_id);
    }

    @Override
    public void onCallMediaState(OnCallMediaStateParam prm) {
        Media media = getMedia(0); // 获取视频媒体

        if (media != null && media.getType() == pjmedia_type.PJMEDIA_TYPE_VIDEO) {
            VideoMedia videoMedia = VideoMedia.typecastFromMedia(media);
            VideoWindowHandle videoWindowHandle = new VideoWindowHandle(videoView);

            try {
                videoMedia.startVideo(videoWindowHandle); // 将视频流绑定到SurfaceView上
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    public void setVideoView(SurfaceView view) {
        videoView = view;
    }
}

public class MyCall extends Call {
    // ...

    public void stopVideo() {
        Media media = getMedia(0); // 获取视频媒体

        if (media != null && media.getType() == pjmedia_type.PJMEDIA_TYPE_VIDEO) {
            VideoMedia videoMedia = VideoMedia.typecastFromMedia(media);

            try {
                videoMedia.stopVideo(); // 停止视频流
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}