When loading contacts the app hangs, because serializing the contacts is done on the main thread

[noamraph]

Hi, when I run the simple example, the GUI stops for some time, instead of having the circular progress indicator continue spinning until the contacts are shown. I first reported it here flutter/flutter#91992 , but now I understand this is a flutter_contacts issue. See a video here:

flutter-slow-contacts.mp4

I checked, and I'm pretty sure that the cause is that serializing the contacts is done on the main thread. I checked this by replacing this line:

                    GlobalScope.launch(Dispatchers.Main) { result.success(contacts) }

With this:

                    GlobalScope.launch(Dispatchers.Main) { result.success(contacts.subList(0, 5)) }

Meaning that all the contacts are retrieved from the phone, but only the first 5 are sent to the flutter app. In this case, the app doesn't hang.

I would be happy to try to fix this and send a pull request. I already managed to move the serialization to a thread in a sample app. However, android studio can't analyze the android directory for some reason, so it makes fixing this much harder. I reported it here: #31

Thanks,
Noam

[joachimvalente]

Hi @noamraph

Thanks for looking into this and working on a PR! As I said on the other thread I'm not sure how to fix the static analysis issue.

Do you have a draft PR though? Or could you tell me the idea? If you're not able to send a fix because of static analysis, I could give it a shot.

[noamraph]

Hi @joachimvalente , I pushed what I have as a PR: #33

There is still non-responsiveness - I haven't managed to move everything to a thread. The change in kotlin might be worthwhile to merge.

Thanks for all your work, it's very helpful!
Noam

[marcodecarolisidt]

I wonder if the issue is causing this:

thread #47, name = 'DartWorker', stop reason = EXC_BAD_ACCESS (code=1, address=0x680)

Sometimes my app crashes

[aytunch]

Hi, for users having too many contacts, app gets janky on startup. Is there any plans to make any enhancements?