Taking attendance without a connection

Who: owner and instructor. For rooms with no Wi-Fi or mobile network.

Getting ready

Open Today with a connection before class, at least once in the day. The day's schedule and the day's attendance sheets are then kept on the device. Without this, the sheet cannot open offline.

Without a connection, the app shows "Offline · data from {time}" (the time of the last update). An offline copy from another day shows its date and offers no Take attendance button.

During class, without a connection

Open Today and tap Take attendance.
Mark students as usual (see the Attendance article). Every tap is kept on the device: closing the app loses nothing.
Tap Finish · N present. The message "Saved on this device · will be sent when the connection returns" is shown. The session gets the To send badge and the button becomes Edit (you can still correct the waiting list).
A panel "N session(s) to send" lists what is waiting.

Sending

It goes out by itself: when the connection returns, when the app starts and every 30 seconds.
Send now forces an immediate try.
A send with no answer after 15 seconds is abandoned and tried again later.
A repeated send never creates a duplicate.

Session states in the panel

To send: waiting, nothing to do.
Not sent: the server refused the send (for example the instructor's 7-day limit has passed). A message gives the reason. Remove deletes the session from the device; the owner must then enter the attendance.
In conflict: someone else saved this session. Tap Choose, then Keep my list or Keep theirs.

Expired session

This is not a panel state but a message: "Session expired: sign in again. The attendance stays on this device and will be sent afterwards." Sign in again; sending resumes afterwards.

What stays on the device

First names, initials, groups and attendance. Never contact details (emails, phones).
The data is tied to the signed-in account.
It is erased at sign-out (for the account signing out) and after 7 days (for every account that was used on the device). Sessions "To send" are never erased by the 7-day limit.
Signing out with unsent sessions shows the warning "N session(s) have not been sent yet and will be lost." Choose Sign out anyway to continue, or cancel to wait for sending.
Signing out needs a connection. Without a connection, sign-out is refused: the message "Cannot sign out without a connection. Try again once online: your attendance stays on this device." is shown, the person stays signed in and nothing is erased. Try again once the connection is back.
With a connection, signing out succeeds even if wiping the device fails (an error message is then shown).