Turn Android Wifi On/Off

To turn Wifi ON:

WifiManager wifiManager = (WifiManager)getBaseContext().getSystemService(Context.WIFI_SERVICE);

wifiManager.setWifiEnabled(true);

To turn Wifi OFF:

WifiManager wifiManager = (WifiManager)getBaseContext().getSystemService(Context.WIFI_SERVICE);

wifiManager.setWifiEnabled(false);