I have a mobile iOS app that uses Google Analytics.
Recently I have been receiving hits in my reports that are clearly not coming from my app. I guess someone must b
I don't have a mobile view to test with, but based on web tracking the following seems to work:
Make sure that "Field A required" and "Override Output Field" are checked
Create a second filter, custom, include
It seems advanced filters do recognize if a field is empty via the "Field Required" setting. So the custom field is set only when the field is not empty, and you can subsequently use a second filter to include only visits that have the field set (thereby excluding hits that haven't the field set)
To illustrate my less than brilliant instructions, the following worked for me: