I am developing an Android App. In which everything is working right. My app is ready to launch. But there I need to implement one more feature. I need to display a popup wh
I think what you are trying to do is probably counter-productive.
Making it easy for people to rate apps is generally a good idea, as most people who bother do so because they like the app. It is rumoured that the number of ratings affects your market rating (although I see little evidence of this). Hassling users into rating - through nag screens - is likely to cause people to clear the nag through leaving a bad rating.
Adding the capability to directly rate an app has caused a slight decrease in the numerical ratings for my free version, and a slight increase in my paid app. For the free app, my 4 star ratings increased more than my 5 star ratings, as people who thought my app was good but not great started to rate it as well. Change was about -0.2. For the paid, change was about +0.1. I should remove it from the free version, except I like getting lots of comments.
I put my rating button into a settings (preference) screen, where it does not affect normal operation. It still increased my rating rate by a factor of 4 or 5. I have no doubt that if I tried nagging my users into making a rating, I would get lots of users giving me bad ratings as a protest.