Office Hours — Today, April 6

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Apr 6
3:50 PM
Mark M.
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Mark M.
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4:25 PM
Randy
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Mark M.
hello, Randy!
how can I help you today?
Randy
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Hi Mark,

I’m building this journaling app (https://github.com/randroid88/TodayILearned) and I don’t yet want to introduce a back end. I’d like it to be an offline app for now.

I’d like to add a feature where users can add images to their posts. Do you think it would be viable to pick the image through the Storage Access Framework and then save the Uri in my app’s Room DB? Or would I likely need to make a copy of the image just for my app?
Mark M.
IMHO, it depends on whether you want to consider this operation to be "linking images to the post" or "attaching images to the post"
4:30 PM
Mark M.
"linking" implies that the post is somewhat decoupled from the image, and so if the image gets deleted or moved, and your Uri is no longer valid, the user will not be horrified
"attaching" (or "importing") implies that the image is truly a part of the post, and therefore should still work even if the selected image is moved or deleted
in the latter case, make a copy
in the former ("linking") case, persisting the Uri should be OK
or, give the user the option of which to do
Randy
That makes sense. Do you see a problem copying too many images for a single app though?
Mark M.
well, it consumes extra storage space, which isn't great if the images in question are photos (and therefore typically not small)
if you think you can nail the UX, offering the choice also helps to educate the user about the storage space issue
Randy
That's kind of what I was thinking. As long as I have good messaging about the limitations of an offline app, hopefully that will be fine. I can then think about adding a back end service later.
4:35 PM
Mark M.
if you are implying that eventually you will upload the images to a server, that basically consolidates the choices, as everything turns into making a copy, just a remote one
Randy
If I had a list of all the URIs, couldn't I fetch them at the time of back up?
At least the ones that haven't been moved/deleted
Mark M.
yes -- once you introduce a server, though, the question becomes: what is the system of record
your use of "back up" suggests that the device is still the system of record, in which case the linking/attaching distinction remains
in many other cases, the server becomes the system of record, in which case your app has a cache of some images and downloads them from the server as needed
4:40 PM
Randy
That actually leads into the syncing question which I haven't found a good answer for. The recommended Android Architecture seems to hint that you should always read the images from the Room DB. I get that the server can still be the source of truth and just asynchronously update the local DB when the data comes in. Where it gets fuzzy is how you keep the two in sync if the user is using the app when offline.
Mark M.
that gets tricky and is really app-dependent
for example, if the user has ways of manipulating the server-side data by other means (e.g., Web app), then things get seriously complicated
Randy
Okay, that's what I figured. Wanted to make sure I wasn't overlooking a simple solution.
4:45 PM
Randy
Thanks, Mark. I might drop-in to another office hours in the future when I get deeper into this work.
4:50 PM
Mark M.
sounds good!
5:00 PM
Mark M.
that's a wrap for today's chat
the transcript will be posted to https://commonsware.com/office-hours/ shortly
the next chat is Tuesday at 7:30pm US Eastern
have a pleasant day!
Randy
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Mark M.
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← Thursday, April 4

 

Office Hours

People in this transcript

  • Mark Murphy
  • Randy