AWSLexVoiceButton prompting and client fulfillment response

Question

I am using the AWS SDK to add a AWSLexVoiceButton to my app. I have it configured for client fulfillment in the Intent I set up, as I want to make the app show something on the screen based on voice command in the AWS Console for my Intent:

This all works, and I get a callback in the code below when the Bot recognizes my Intent:

func voiceButton(_ button: AWSLexVoiceButton, on response: AWSLexVoiceButtonResponse) {
    // `inputranscript` is the transcript of the voice input to the operation
    if response.dialogState == .readyForFulfillment {
        print("Ready to fulfill")
        // I want to provide speech output
        say(text: "OK, I will show the train status screen")
        showTrainStatusScreen()
    }
}

Two problems:

1. When I tap the AWSLexVoiceButton, there is no audio indication that it is listening, and you see no indication you even tapped on the button unless you make a loud enough sound to cause its microphone sound detection animation. I can find no way to add a voice prompt like "How can I help you?" because there are no AWSLexVoiceButtonDelegate callbacks when the button is initially tapped.

   Q: Is there any way to add an audio prompt when Lex beings listening?

2. Similarly, there is no audio indication that the client is fulfilling the intent. Because there is a callback, I can add my own response. But to do so, I manually set up a AVAudioPlayer and integrate with AWS Polly to convert my text to speech in a custom say method I wrote. My approach works, but it seems like it must be the wrong way.

   Q: Is there any way to trigger Lex to give a custom audio response as a result of client fulfillment?

Answer 1

1. You cannot provide a response via Lex without a request from the user. I'm not familiar with iOS, however in Android you can add this functionality within your application to handle this situation manually. I would guess iOS allows similar functionality. Please comment if I am wrong. Unfortunately, this is not something that Lex provides.

2. Lex will only respond once the fulfillment is complete. Since you do not require server side fulfillment, you can create a lambda function which does nothing except return the completion response you are looking for.

Hope that helps