I've been searching how to do this in Android and I found this question:
How to make a phone call in android and come back to my activity when the call is done?
Which contatins this piece of code:
String url = "tel:3334444";
Intent intent = new Intent(Intent.ACTION_CALL, Uri.parse(url));
Which opens the dialing activity and dials to the number specified in the second parameter. The problem is the I need to open the dial activity without start to dial immediately, but with the number in the second parameter already inserted into the number textbox.