When there’s no signal

A basement, a barn, or a shop with thick walls doesn’t stop you cataloguing. The app keeps a copy of your library’s text on the phone — every book’s title, authors, and identifiers — so the question that matters most in a shop, "have we got this already?", is answered instantly and without a connection. A band across the top says Offline while you are, and tells you how long ago the copy was synced once it’s old enough to be worth doubting.

1. Keep scanning. Each book still tells you at once whether you own it or have it on the want list, answered from the copy on the phone. For a book with no barcode, "Check a book" searches that copy by title — every owned and wanted book, with the year, publisher and edition where it knows them.
2. A book you don’t own is saved rather than added — the result reads "Saved for later", and a count of waiting scans appears on the Scan screen and as a mark on the Scan tab.
3. Carry on down the shelf. Nothing is lost if you close the app, and nothing is lost if your phone restarts.
4. When the signal returns, the waiting scans are sent on their own — you don’t have to do anything. A "Queued scans synced" message tells you what happened: how many books were added, and how many turned out to be in the library already.

You can see the waiting scans at any time by tapping the count on the Scan screen. Each one shows its code and where it has got to — "Waiting to sync", "Added", or a reason it needs you. A few can’t be settled without you: a code the catalogue doesn’t recognise, or one matching several editions. Those wait in the list with the reason shown, and you finish them from there using the same screens as a live scan. If you have a signal but our server isn’t answering — for a minute during an update, say — a scan is saved the same way instead of failing, and the result says the server didn’t answer. A saved scan the server can’t take yet waits a little and is tried again by itself, waiting longer each time, while the app is open; after several tries it says the server could not be reached and offers Try again. A scan also waits for the library it was made in: if you switch to another library before it has gone through, it is listed under “Waiting for” that library’s name, with a button to switch back and send it. The app never switches library by itself. You can also delete any scan you’d rather not keep. When the list reads "Nothing waiting", every scan has gone through.

Two kinds of thing deliberately wait for a signal: correcting a book’s details — including reading a description off the jacket, which is a correction like any other once you save it — and anything to do with photographs, whether taking one, choosing one, promoting one to cover, or removing one. The book screen says so and greys them out rather than letting you start. Corrections are replayed against a record other people may have changed meanwhile, and there’s no safe way to settle that later; neither photographs nor read descriptions are held on the phone for later either, so nothing queues up unseen. Better to tell you now than to lose your work quietly.

Browsing offline works too, from what you last loaded: books you’ve already seen still list and open, and cover images are replaced by plain tiles. Covers are the one thing not kept on the phone, which is what makes the offline copy small enough to hold a collection of thousands.

• Getting Started →
• Adding Books →