I have 2 android devices, one is mine and the other is my son's. I have them both logged into facebook and I cannot see his and he cannot see my city. Irritating. Also the same is true for Google Play. Log in on both devices and no friend icon.
I actually had this resolved as a couple days after trying the delete/re-add BuildIt from Facebook, I could see a friend.
Then after the recent app update last week, I can no longer see friends. And as was the case before, friends can see me.
I fixed mine today! I used a combination of suggestions combined with some experimentation. Details below (These are based on my Galaxy Note 4)
1. Go to your Facebook on a desktop PC. Click on Settings, then click on Apps
2. Search for and click on SimCity Build It
3. At the bottom of the pop-up window, click 'Remove App'. After it's complete, close Facebook
4. Go to Applications on your cell device. Click on SimCity and click the 'Clear Data' button. (If using an iPhone device, you must delete and re-download the app)
5. Open SimCity and complete the first few "missions" until you are able to click on settings and "Log in to Facebook" again
6. Once you've logged in and allowed Facebook permissions, you should now see your friends. This worked for both my wife (iPhone) and myself (Android). Hit me up with feedback!
Yes. It deletes the data on your device, but once you log back into Facebook, it asks if you would like to import your previous saved city. It's saved on a server and connected to your Facebook.