Monetization in an Android application at a certain stage?

Question

Android

Good afternoon!
The bottom line is this: for example, there is an application for calculating the cost of food.
Monday
products quantity amount
apples 12 kg 65r
Tuesday
products quantity sum
apples 5 kg 10r
Wednesday
products quantity sum
pears 5 kg 10r
How to make an offer to buy the full version of the application when you try to start recording on Thursday?

Answer 1

Your users only eat Apples and Pears, what is the purchase of the full version of the application? Have pity on the vegan... But seriously, do you need to know if it is connected with some kind of backend? If so, then do it on it. If not, you can write to the record counter and pop up a message box when the value is reached. We read about - Preferences. And it's best to stick to the date.