I successfully connected to Raspberry pi3 (android things preview image) via following command
adb connect <ip-address>
but after to connect Wifi using following command :
adb shell am startservice \
-n com.google.wifisetup/.WifiSetupService \
-a WifiSetupService.Connect \
-e ssid dsid \
-e passphrase am@sin305
it gives following error msg :
Error: No intent supplied
Problem solved already : By following changes (Don't comment now) - Tip : remove all backslash from above command.
now it's connected to Wifi successfully.