I have decided to change the form design itself to avoid the error mentioned in my post, but now I have been struggling with previewing/deploying the updated form. Now the above-mentioned issue (Unexpected token < in JSON at position 0) does not occur but currently my survey form cannot be previewed/deployed in KoBoToolbox.
When I upload the file and go into preview, it continues to load the form for more than 10 minutes and does not show the preview. Deploying the form was also failed.
I checked the form using XLSForm Online v2.0.
It returned that the default value used in geopoint-type questions “-6.175628 106.82699” are not acceptable. I deleted it and the remaining warnings are only “Question has no label”. I suppose it is no problem if I intend to do it. Then the form could be displayed from “open in the browser”.
However, when I upload the file in KoBoToolbox, it won’t work.
I hope if you could find any issues in my form.
In “choice” sheet, I deleted the list of address and changed the setting as shown below.
I faced the following issue but it resolved after deploying the form.
Preview does not accept select_one_from_file showing an error message “invalid data_type: select_one_from_file address.csv”
I suppose it will be avoided by deploying it and also understand that this type is available in deployed questionnaire, not Android App according to this post: Error message while previewing a form when using select_one_from_file.
-My concern was that whether filter function works well or not in an external file. I am using three columns in “choice” sheet relevant to desa (and also province, kota and kecamatan, all are used in conjunction with desa). However it worked properly.
For the sake of simplicity, I embedded all administration names in different levels (province, kecamatan and desa) in one csv file but I realized that it does not work well as the lower administrative sections appeared in the upper select_one question.
I simply keep major sections (province and kota, which have only a few records) in the main file then exported lists of kecamatan and desa into csv files separately. It worked out perfectly. Thank you.