API for configuring static IP addresses in an Android application

Settings.System includes several flags you can use for this:

• WIFI_USE_STATIC_IP
• WIFI_STATIC_IP
• WIFI_STATIC_NETMASK
• WIFI_STATIC_GATEWAY
• WIFI_STATIC_DNS1 and WIFI_STATIC_DNS2

You'll also need the android.permission.WRITE_SETTINGS permission declared for your application.

Then in your activity:

final ContentResolver cr = getContentResolver();
Settings.System.putInt(cr, Settings.System.WIFI_USE_STATIC_IP, 1);
Settings.System.putString(cr, Settings.System.WIFI_STATIC_IP, "you.re.ip.addr");
// call putString() for each value to set for your interface

If you want to change the IP address of the carrier's 3G/4G,etc interface, I do not believe this is possible - as it is connected to the carrier and uses their DHCP/security for enabling you to connect and use their services (sort of like changing the external IP of your cable modem without the consent of your ISP).