STOP action implementation in SUSI iOS

You may have experienced, you can stop Google home or Amazon Alexa during the ongoing task. The same feature is available for SUSI too. Now, SUSI can respond to ‘stop’ action and stop ongoing tasks (e.g. SUSI is narrating a story and if the user says STOP, it stops narrating the story). ‘stop’ action is introduced to enable the user to make SUSI stop anything it’s doing.

Video demonstration of how stop action work on SUSI iOS App can be found here.

Stop action is implemented on SUSI iOS, Web chat, and Android. Here we will see how it is implemented in SUSI iOS.

When you ask SUSI to stop, you get following actions object from server side:

"actions": [{"type": "stop"}]

Full JSON response can be found here.

When SUSI respond with ‘stop’ action, we create a new action type ‘stop’ and assign `Message` object `actionType` to ‘stop’.

Adding ‘stop’ to action type:

enum ActionType: String {
... // other action types
case stop

Assigning to the message object:

if type == ActionType.stop.rawValue {
message.actionType = ActionType.stop.rawValue
message.message = ControllerConstants.stopMessage
message.answerData = AnswerAction(action: action)

A new collectionView cell is created to respond user with “stoped” text.

Registering the stopCell:

collectionView?.register(StopCell.self, forCellWithReuseIdentifier: ControllerConstants.stopCell)

Add cell to the chat screen:

if message.actionType == ActionType.stop.rawValue {
if let cell = collectionView.dequeueReusableCell(withReuseIdentifier: ControllerConstants.stopCell, for: indexPath) as? StopCell {
cell.message = message
let message = ControllerConstants.stopMessage
let estimatedFrame = self.estimatedFrame(message: message)
cell.setupCell(estimatedFrame, view.frame)
return cell

AVFoundation’s AVSpeechSynthesizer API is used to stop the action:

func stopSpeakAction() {
speechSynthesizer.stopSpeaking(at: AVSpeechBoundary.immediate)

This method immediately stops the speak action.

Final Output:

Resources – 

  1. About SUSI:
  2. JSON response for ‘stop’ action:
  3. AVSpeechSynthesisVoice:
  4. AVFoundation:
  5. SUSI iOS Link:
  6. SUSI Android Link:
  7. SUSI Web Chat Link:

Published by

Jogendra Singh

Google Summer of Code '18 | Self-taught Programmer | Developer | Open Source & Swift Enthusiast | iOS Engineer | UI/UX Designer | Developed Web and Windows Apps