Customize zoom UI but screen is just black

Meeting SDK Android
1

I’m trying to customize the zoom UI, but the video is not display on the screen. It just black.

I have enabled the custom UI feature:

meetingSettingsHelper.setCustomizedMeetingUIEnabled(true);

When join the meeting:

if (meetingStatus.toString().equals("MEETING_STATUS_INMEETING")){
                        executeInMeetingTask(); //inMeetingListener
                        setContentView(R.layout.activity_zoom_view);
                        MobileRTCVideoView videoView = findViewById(R.id.videoView);
                        viewManager = videoView.getVideoViewManager();
                        ...
                    }

my inMeetingListener:

...
            @Override
            public void onMeetingActiveVideo(long l) {
                Log.d("...", "inMeetingServiceListener: onMeetingActiveVideo" + l);
                MobileRTCVideoUnitRenderInfo info = new MobileRTCVideoUnitRenderInfo();
                viewManager.removeAllVideoUnits();
                viewManager.addAttendeeVideoUnit(l, info);
            }
...

my layout:

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <us.zoom.sdk.MobileRTCVideoView
        android:id="@+id/videoView"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:background="#0bd4cd" />
</LinearLayout>

When I turn on the camera of participant (from other device), the log is:

inMeetingServiceListener: onMeetingActiveVideo16778240

But nothing change. The screen is still black.
( I’ve change the color of videoView to #0bd4cd. When join the meeting, the background is changed to #0bd4cd, and change to black straightway).

I’m using SDK version 6.1.5.23231

Can anyone tell me where I am wrong?
Thank you for any help.