Make App-To-Phone Call Using iOS and Flutter

We built an iOS application using Flutter that makes a call from a mobile application to a physical phone number using Vonage Client SDK. The application has three screens: Prerequisites, Login as Alice, and Make a Phone Call. To build the application, we installed the required packages, including permission_handler for requesting microphone permissions, and set up the Vonage CLI and Flutter SDK. We also implemented the login functionality using the Vonage Client SDK, which authenticates the user Alice and generates a JWT token. The application then makes a call to a physical phone number and handles the call state changes using the NexmoCallEventListener listener. Finally, we added the functionality to request microphone permissions and end the call when it is answered or ended by the callee.