How to create a button in SwiftUI that, when tapped, automatically starts the call in one action (not using tel: hyperlink)?

Question

Currently, I have created a button that, when tapped, launches a phone number as a hyperlink in SwiftUI:

Button(action: {
    guard let phoneNum = URL(string: "tel://1-123-456-7890") else {return}
    UIApplication.shared.open(phoneNum)
}) {
    Text("Call number")
}

The issue is that this, when clicked, first opens up a prompt asking "Call 1 (123) 456-7890?" with the chance to cancel. Thus, this button isn't a one click option to automatically begin a phone call.

Is there a simple way that a button, when being tapped, automatically launches a phone call after a single tap without having that prompt in between?

I was hoping that this code above would automatically launch a phone call, like what happens when you use URL in SwiftUI to open up a webpage with one tap. However, with phone numbers, there seems to be the prompt in between.

Edit: If not a simple solution, is there any solution that retains this style of having a button that launches a phone number from a string?

Answer 1

Yes, you can achieve this using the CallKit library in iOS. This library allows your application to initiate phone calls without user confirmation. Here's how to achieve this in SwiftUI:

First, make sure you have added this permission in the application's Info.plist file:

<key>NSMicrophoneUsageDescription</key>

<string>We need access to your microphone to make calls.</string>

Then you can use the following code to make the call:

import SwiftUI
import CallKit

  struct ContentView: View {
    let callController = CXCallController()

var body: some View {
    Button(action: {
        let handle = CXHandle(type: .generic, value: "1234567890") 
        let startCallAction = CXStartCallAction(call: UUID(), handle: handle)
        let transaction = CXTransaction(action: startCallAction)
        
        callController.request(transaction) { error in
            if let error = error {
                print("Failed to start call: \(error.localizedDescription)")
            } else {
                print("Call started successfully")
            }
        }
    }) {
        Text("Call number")
    }
}

}