How do I detect that localisation has occured?

Question

When utilising a Tango what would I use, callbacks or otherwise to detect when the devise has localised to a previously loaded ADF?

This is mainly for UI purposes in conjunction with Tango UX, telling a user to walk around an environment.

Answer 1

Localization may be detected when your TangoPoseData with a frame of ADF comes back valid.

Look at the Tango Java examples of AreaLearningActivity with this simplified logic:

//tell tango to provide pose for ADF
ArrayList<TangoCoordinateFramePair> framePairs = new ArrayList<TangoCoordinateFramePair>();
framePairs.add(new TangoCoordinateFramePair(
        TangoPoseData.COORDINATE_FRAME_AREA_DESCRIPTION,
        TangoPoseData.COORDINATE_FRAME_DEVICE));

//register a listener for the frames chosen
mTango.connectListener(framePairs, new OnTangoUpdateListener() {

  //listens for updates from tango pose
  public void onPoseAvailable(TangoPoseData pose) {

    //base frame of ADF provides coordinates relative to the origin of the ADF
    if (pose.baseFrame == TangoPoseData.COORDINATE_FRAME_AREA_DESCRIPTION
        && pose.targetFrame == TangoPoseData.COORDINATE_FRAME_DEVICE)

      //if the status is valid then localization has succeeded
      if(pose.statusCode == TangoPoseData.POSE_VALID){
        Log.i(TAG,"Successfully localized with ADF");
      }
    }
  }

Your config must indicate which ADF is of interest:

 config.putString(TangoConfig.KEY_STRING_AREADESCRIPTION,adfId);

This process is not easily observed from the code, but I discovered it debugging the AreaLearningActivity example. The Java API would benefit from a higher level of abstraction making the common scenario you requested more obvious and easier to use:

TangoLocalizer.builder().register(myListener).adfId(myAdfId).build();