Mediacontroller未显示在videoview的自定义警报对话框中

Question

我使用以下代码在自定义提醒对话框中显示视频，但媒体控制器未显示在自定义提醒对话框视频视图中。

private void playvideo() {
        final Dialog dialog = new Dialog(this);
        dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
        dialog.setCancelable(false);
        dialog.setCanceledOnTouchOutside(false);
        dialog.setContentView(R.layout.playvideo);
        dialog.show();
        /*WindowManager.LayoutParams lp = new WindowManager.LayoutParams(
        LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
        lp.copyFrom(dialog.getWindow().getAttributes());
        dialog.getWindow().setAttributes(lp);*/
        WindowManager.LayoutParams a = dialog.getWindow().getAttributes();
        a.dimAmount = 0;
        dialog.getWindow().setAttributes(a);
        MediaController mc = new MediaController(dialog.getContext());
        getWindow().setFormat(PixelFormat.TRANSLUCENT);
        final VideoView videoview = (VideoView) dialog.findViewById(R.id.surface_view);
        Uri uri = Uri.parse(fileData2.toString());
        videoview.setVideoURI(uri);
        videoview.setMediaController(mc);
        mc.setAnchorView(videoview);
        videoview.start();

        ImageView playvideoclose=(ImageView)dialog.findViewById(R.id.playvideoclose);
        playvideoclose.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
            videoview.stopPlayback();   
            dialog.dismiss();

            }
        });

    }

请事先帮助我。