Building the interface

To be able to place the call, you need to add two elements to the screen:

• A UILabel to show the connection status
• A UIButton to start and end calls

Open ViewController.swift and add these two programmatically by replacing the entire file content with the following:

import UIKit
import NexmoClient

class ViewController: UIViewController {

    var connectionStatusLabel = UILabel()
    var callButton = UIButton(type: .roundedRect)

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.

        connectionStatusLabel.text = "Unknown"
        connectionStatusLabel.textAlignment = .center
        connectionStatusLabel.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(connectionStatusLabel)
        view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-20-[label]-20-|", 
          options: [], metrics: nil, views: ["label" : connectionStatusLabel]))
        view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-40-[label(20)]", 
          options: [], metrics: nil, views: ["label" : connectionStatusLabel]))

        callButton.setTitle("Call", for: .normal)
        callButton.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(callButton)
        view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-20-[button]-20-|", 
          options: [], metrics: nil, views: ["button": callButton]))
        view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[label]-40-[button(40)]", 
          options: [], metrics: nil, views: ["label" : connectionStatusLabel, "button": callButton]))
        callButton.alpha = 0
        callButton.addTarget(self, action: #selector(callButtonPressed(_:)), for: .touchUpInside)
    }

    @IBAction func callButtonPressed(_ sender: Any) {

    }

}

The callButton has been hidden, its alpha is set 0, and will be shown when a connection is established.

Also, a target has been added for when callButton is tapped and will be used to place and end calls.

Build and Run

Run the project again (Cmd + R) to launch it in the simulator.

The callButton has been hidden, its alpha is set 0, and will be shown when a connection is established.

Also, a target has been added for when callButton is tapped and will be used to place and end calls.