Add loading state to slider widget

[seadowg]

The range question now supports displaying labels based on a list in the form via tick-labelset. There is (small) a risk that loading those labels could cause the app to freeze. Given that, the labels should be loaded off the Andorid UI thread and a loading state should be shown while that happens:

In addition, form progress (forwards or back) should be blocked while the question loads to prevent the user from missing the question.

[seadowg]

@alyblenkin there are probably many widgets that should have loading states to prevent freezes, but I think this is a good one to consider first as we've just worked on it. Let me know if you want to discuss at all!

[alyblenkin]

Good point! What about something like this? I liked the direction we were heading with the states for downloading forms and tried to build on that. Let me know what you think.

[seadowg]

Yeah, that's nice! We can now the question text instantly as well so that works to display it like that. I guess we'll probably want to block back/next while loading happens right?

[alyblenkin]

@seadowg - awesome! I don't think we should block it because what if it's not a required question.

[seadowg]

@seadowg - awesome! I don't think we should block it because what if it's not a required question.

So just allow the user to move on before the "answer view" loads? I was thinking we might want to block until they've at least had a chance to see it.

[alyblenkin]

Is there any risk of it not loading?

[seadowg]

Is there any risk of it not loading?

Good question! I think only in such an exceptional state that we'd want to crash the app/exit the form.

[alyblenkin]

Ok sounds good. We could block the back/next buttons until it loads.