Hi. I had a quick look at the survey. Thanks for sharing. I was able to make it load in my iPhone6 in 4 seconds. Here are the changes I made:
- First I changed the appearance of long lists into 'minimal'. This helps because the choices in the list are loaded only when you tap on the drop-down. I left short lists (under 5 choices) as they were. I got marginal improvement in this particular case.
- Then I looked at your relevant column to find sets of questions using the same expression. I found a couple large sets in section 22 (Gastos) so I first removed all the relevant expressions, then grouped the questions and applied the relevant expression to the Group. In this manner, the mobile app only needs to execute the relevant expression once for the group as opposed to every question. The survey started to make some noticeable improvements here.
- Then at the very beginning of the survey, in Section 3 (Codigo Encuestador), I collapsed a sequence of questions into a single Cascading Select with External Choices. This also made a significant difference.
- I applied minimal appearance to your repeat. By using minimal appearance you delay the rendering of questions within the repeat until you click on Plus. Made minor difference but applied anyways.
- Fixed typo in the header (Settings Worksheet), applied like-rt appearance to Encuesta de Satisfaccion. Just for the looks, no chance in performance.
I noticed you are using the field-list appearance. Unfortunately we are not supporting this XLSForm feature just yet. I left them there although they will be ignored in the app.
I imagine we could look at optimizing a bit more, but that is how far I was able to get it for now. For a survey of this type, which typically would take several minutes to complete, it seems like 4 seconds to open should be bearable. I did not test on other devices, the time to load will change depending on the compute time in the phone or tablet.
Attaching survey with my changes.
