Cannot get admin_notices to be triggered!

Hi everyone,
Im using method #2 on this page: https://wordpress.stackexchange.com/questions/127818/how-to-make-a-plugin-require-another-plugin

Basically i just copied the code and inserted into my “child-plugin”, and replaced the path to parent-plugin.
The problem is that admin_notices wont get triggered, so the function supposed to show my warning-message wont run.
Everything else in the code is working, including the deactivation on the plugin.

Any ideas on why the hook wont trigger?
Im running multisites, if that matters.

Question number 2 i guess would be if theres any alternative hooks that would fit here? Basically i just want to tell the user that he needs another plugin for this one to run.

Thanks!