How to hide photo and video in Android mobile app ( timer locker app )

Dosto is video me maine aap logo ko bataya hu ki kyse aap apne parsal photo or video ko apne hi mobile me chhupa sakte hai ek app ke madat je jise koi bhi nahi khol sakta bahot se log bolte hai ki ham apne mobile me apne photo ko kyse chhupaye,ham apne video ko kyse chhupaye .To ye video maine unke liye hi banai hai to aap is video ko pura dekhe

Or is app ko downlod karne k liye niche link pe click kare