problems with in-app purchase

[Monk]

Can you tell me fernando why the line 31 when I tested my app in Google play and set my key sometimes the line work sometimes not

[Tiny]

Monk, it will take a lot of reading on google developer pages before you get a grip of it all. At least for me it took a couple of months before I understood enough to make the game work with IAP. Follow Google developer steps and then watch the video and read the in-app objects help file Fernando suggested.

Unfortunately there are no shortcuts or easy way to get it working. But I'm sure you will succeed with some endurance.