I want to forward calls in a simple way, just by clicking a button.
Forwarding the call is done by dialing a GSM service code. However, after doing this, a popup window appears that tells if the action was successful or not.
Is there any way to suppress or close this popup window programmatically?
If you're asking about USSD codes used by GSM/UMTS than no, there's no way to suppress or close the confirmation popup.
The API was requested in the ticket below, but remains unresolved: