List item count is zero in SharePoint apps:

If you are getting the count as zero even the data exists means that you don’t have item level permissions. Please follow up the below steps to give permissions at the list item levels in apps.

Another way to add permissions:

Just right click on “Appmanifest.xml”, select “view code” and then add the below code in it.

Note: Don’t submit your app with “Full Control” rights to the “Office Store”. Reason is Office store apps allowed only Read, Write, and Manage permissions. Your app is blocked if you try to submit an app to the office store that requires “Full Control” rights.

The Reason is: Apps that include an app web automatically get full control of the app web. Also, because the block is in the Office Store submission pipeline, apps that request more than Manage permissions can still be deployed through the app catalog.

Correct one:

Just re-deploy the app again to the store. Now you should get the items count now.

Please let me know if still have any issues.