CallBar for iOS 7 cydia tweak re-designs the incoming call view to allow you to use your device while it’s ringing or while in a call.
Notification Center integration, complete call handling for telephony and FaceTime audio calls, completely new UI, bigger and easier to access with instant dismissal with just a swipe and a whole new and complete dialer interface which can actually replace the Phone.app.
Answer, decline or dismiss a call with ease without stopping what you’re doing. You can pick up a call and stay where you are while in any application. Even place calls from anywhere by activating the dialer interface with an activation method of your choice.