wifi and static IP address

Many articles can be found on setting up a static IP address for an ethernet connection, but when it comes to a wifi static connection ... I got lost. So instead, I used an easier way:

• install a compatible USB wifi dongle (this is a Realtek module and worked out of the box)
• login to your pi's desktop, using VNCserver
• on the desktop you will find an icon: WiFi-Config
• open this program and press "scan": the available wifi networks will be shown
• select your network and enter the wifi password in the PSK box
• press OK and click connect 
• in the menu bar above, click "file" and choose "save configuration"

(These credentials are now stored in the file located at: /etc/wpa_supplicant/wpa_supplicant.conf)

You are now connected to your wifi network, but still don't have a static IP address! So, 

• in a terminal window (Mac or Pi) type:
• cd /etc/network (moves you to the directory network under the etc directory)
• sudo nano interfaces (opens the file "interfaces" with the nano editor)
• the contents of the file should be the following: of course, I chose 192.168.1.18 as my static IP address, you are free to choose any other number provided it is within the range of addresses available on your router. 

• "netmask" can be found if you enter the command: "ifconfig"
• "gateway" is your router's home page

 You should now be able to go wireless!