Back key not working web-mobile

Hi I am trying to run my game in web view so I exported build as web-mobile and launched it through android web-view on android device. everything works fine but I am unable to capture Android back button in my game, till now I tried

cc.systemEvent.on(cc.SystemEvent.EventType.KEY_DOWN, (event) => {
cc.log(" some event down now "+event.keyCode);
}, this);

but I am not able to even see this log, If I run my game through browser on my laptop then its working fine. Am I missing something here? Should not this code capture Andorid Back button as well if I launch through android web-view? I am working on cocos creator 2.4.3

I can ask engineering once they return from national holiday.

@slackmoehrle any idea when they will be returning so that we can plan accordingly? Also I can see that there is a vip tech support as well in your product sections, so how can I use it ?

Oct 8 back in the office.

Let me look into the state of vip tech support. Last I know it was China only but there were meetings about adding western support.

did you checked if there is any western support available ? Also it would be great If you can tag some users who works in web-mobile or might have an idea about this.

I can ask about VIP support when the team is back in the office later this week.

Clicking the back button will close the game process when the system API Level >= 28 on Android devices.
Adding focus to SurfaceView solves the problem.

If you click on a webView form that is open within the game, it will cause the SurfaceView to lose focus, and then clicking the back button will close the game.
Add the onKeyDown function to to allow the SurfaceView to regain focus before the return key triggers the closing process.
Reference code.