Export iPhone contacts to Android on the Nexus 7
Export contacts on the iPhone
Syncing contacts between the iPhone and Google contacts seems to be quit challaging.
The easiest way I discovered was the following.
Install My Contacts Backup
On the iPhone install the free app "My Contacts Backup". This is a small free app that creates a backup in vcf-format.
Create and send backup of contacts
The app "My Contacts Backup" creates a backup of the contacts on the iPhone and attaches the backup file to an email message. Send the email to your own email address.
Open your mail on your Android device
On the Android Nexus 7 open the incoming mail and save the attached contacts backup file.
Go to downloads on the Android device
On the Android Nexus 7 launch the "Downloads" app.
In the screen listing the downloads, select the attachment. This file is named "MyContactsBackup-<date>-<time>.vcf" When you open this attachment, the contacts are read into the contact-list on the Nexus 7.
Open the People app on the Android
On the Nexus 7 open the People app. Now you find all your contacts here. Make sure you have them synced with Google.
Syncing your contacts with Google
Open Settings, go to Accounts and select Google.
Now you get a list of the data and the setting of the synchronisation. Check the checkbox for Contacts to have them synced with Google.
Now your contacts are not only on your Nexus 7 but also "in the cloud" (as in: in the hands of Google).