How to correctly initialize a fit contributor object from a simpledatafield?

I have a simpledatafield which provides a value. I want this value to be logged if the simpledatafield is used during an activity with logging.

I found the Fitcontributor example in the SDK's samples and understand that i need to create a Field object.

Below is my code. It compiles, but crashes during runtime with error

Error: System Error Details: Failed invoking <symbol>

regarding line 14.

What's wrong here?

import Toybox.FitContributor;

class ForumsladerView extends WatchUi.SimpleDataField {

        private var _fitRecording as FitContributor.Field; // fit recording contributor

        ...

        public function initialize(dataManager as DataManager) {

        ...

        // Create the custom FIT data field we want to record
        _fitRecording = createField(
            "Forumslader", 0, FitContributor.DATA_TYPE_FLOAT,
            {:mesgType=>FitContributor.MESG_TYPE_RECORD, :units=>"FL"}
        ) as FitContributor.Field;

        _fitRecording.setData(0.0);

    }

0 flowstate over 3 years ago

createField() has to be called from SimpleDataField.initialize() -- it won't work if you call it later. I can't tell for sure by looking at your snippet if that's the case or not.

You also need the FitContributor permission to be set in the app manifest.

0 CYBERMAN54 over 3 years ago in reply to flowstate

the code snippet is from my Viewclass which extends Simpledatafield, so for my understand the initialize function here should be the right place?

Permission is set (and if not results to permission error, but not "failed invoking symbol").

0 jim_m_58 over 3 years ago in reply to CYBERMAN54

What device are you trying to use? Sim or real device?

0 CYBERMAN54 over 3 years ago in reply to jim_m_58

Sim.

0 flowstate over 3 years ago in reply to CYBERMAN54

Yeah my point was due to the ellipses and the non-standard indentation in your snippet, it wasn't 100% clear whether createField() was part of initialize() or not. I thought it was, but like I said, I couldn't tell *for sure*.

Have you tried building and running the FitContributor example (which you referred to) in the SDK, as a sanity check? (I assume you're referring to MoxyField)

0 flowstate over 3 years ago in reply to flowstate

Also, did you call SimpleDataField.initialize() at or near the top of ForumsladerView.initialize()?

0 CYBERMAN54 over 3 years ago in reply to flowstate

yes, it is called at top, before createField.

0 flowstate over 3 years ago in reply to CYBERMAN54

What does your app class (which extends AppBase) look like?

0 CYBERMAN54 over 3 years ago in reply to flowstate

is pretty simple, just initialize AppBase and

public function getInitialView() as Array<Views or InputDelegates>? {

var dataManager = _dataManager;

if (dataManager != null) {

return [new $.ForumsladerView(dataManager as DataManager)] as Array<Views>;

}

return null;

}

0 flowstate over 3 years ago in reply to CYBERMAN54

I mean it looks ok, but unrelated to your FIT problem, I'm not quite sure why the app view is returned conditionally in getInitialView()). Can dataManager actually ever really be null, or is that check just to make the type checker happy? Not to state the obvious but your app would never work if it doesn't return a view.

Do you just have the one call to createField()? Have you tried it with a different label or record type?

Have you tried testing with the simplest possible app? (e.g. Just call createField() and return a constant value in compute()?)

Have you tried testing on different devices in the sim?

Have you tried building and running the MoxyField sample (or whatever sample it was that you adapted for this app)?

It seems that someone else is seeing this on real devices, like Fenix 7:

forums.garmin.com/.../datafield---system-error---failed-to-invoke-symbol-on-initialize