On screen navigation keys are embarrassing while talking by viber or any free call APP

[Essharnouby]

Why Sony is making all the phone with On screen navigation keys it is embarrassing while talking by viber or any free call APP we can't enjoy the app because while tacking my face touched the back key, home key and minimize key several times this is so embarrassing. So is there any way to screen off while I put phone on my ear like real call
proximity sensor
sorry for my bad English
Thnx ...

[Johan · Accepted solution]

Yes these are possible to hide by the app developer, so they hide just like when watching video clips or pictures via the album app.

So this is not a setting in the phone, its up to the application to support this.