2_callbackFunction.md

Callback Function

Every voice interaction should implement a callback function. This allows the Voice Assistant to operate the controls

1. Your application must declare the corresponding voice interaction callbacks
2. Once window loads:
   • Pass the callback to webapis.voiceinteraction.setCallback
   • Call webapis.voiceinteraction.listen()
3. This will allow the interaction with the Voice Assistant

e.g. setCallback

window.onload(function() {
    var callback = {
          ...
          onupdatestate : function () {
              ...
          },
          onplay : function () {
              ...
          },
          ...
    };
    ...
    webapis.voiceinteraction.setCallback(callback);
})

Note

All callback functions must be passed as parameters for the webapis.voiceinteraction.setCallback function. These callback functions must only be included if you intend to overwrite their default behavior, otherwise, the only mandatory callback function you must explicitly include is onupdatestate

The listen() function must be called after the webapis.voiceinteraction.setCallback function.

e.g. listen()

window.onload(function () {
    ...
    webapis.voiceinteraction.setCallback(callback);
    webapis.voiceinteraction.listen();
    ...
})

In order to get the proper voice control from the Voice Assistant, you must declare the app status inside the callback function as an Appstate function:

e.g.

webapis.voiceinteraction.setCallback({
  onupdatestate : function () {
    console.log("Assistant tries to get app state");
    return "List";
  }
});

Note

This function is called just before any utterance is processed, so that the Voice Assistant can be aware of the status dynamically. The status can affect a callback function, therefore it's important to return the status as the application's real status.

Possible application states:

Voice Application State	Description	Feature
"None"	Application Default Status.	Same with "Player" Status
"List"	The status of the application showing something as a list.	Based on this status, "Play this", "Play" will work as calling onselection(0); "Previous" will work as calling onnavigation("NAV_PREVIOUS")
"Player"	The status of the application playing content.	Based on this status, "Play this" will work as calling onplay()