adapt-contrib-languagePicker: triggers error if _restoreStateOnLanguageChange enabled

[moloko]

If you have a multilanguage course and are using the option _restoreStateOnLanguageChange, when you switch language you either get an error (v5.6.1) - or no error but you end up on the wrong page (v5.7.0)

In Adapt v5.6.1, this is the error that's being triggered:

In v5.7.0, (using the OOTB content) if you change language from the menu, question components or assessment pages, you end up being sent back to the presentation components page - which is presumably why the above error is being triggered: because languagePickerModel expects 'menuView:ready' to be triggered, but it never is - 'pageView:ready' gets triggered instead.

[moloko]

To fix the v5.6.1 error it looks like this line in languagePickerModel needs to be changed to:

if (!Adapt.findById(this.locationId)) return;

[oliverfoster]

Can change the event listener to contentObjectView:ready in v5.7+

[moloko]

Can change the event listener to contentObjectView:ready in v5.7+

I'm not sure it's the event that's the problem, it's more why is it trying to send you to the course's first page?

[moloko]

For example, in v5.7.0 if i disable the setting _restoreStateOnLanguageChange and then change languages I get sent back to presentation components instead of the menu, changing the event listener wouldn't help with that

[moloko]

I think it's something to do with the _start configuration. even though it's not enabled in the JSON it somehow seems to be getting enabled if I change languages.

[moloko]

In v5.7.0, (using the OOTB content) if you change language from the menu, question components or assessment pages, you end up being sent back to the presentation components page - which is presumably why the above error is being triggered: because languagePickerModel expects 'menuView:ready' to be triggered, but it never is - 'pageView:ready' gets triggered instead.

This is a different issue altogether which has only surfaced in v5.7.0 because of this change. It's still possible to replicate this in earlier v5.x releases

Have moved this over to #2907