I have the following code: ```suspend fun pickSystemImage(): ImageContainer = suspendCancellabl...

# ios

[Philip Dukhov]

I have the following code:

suspend fun pickSystemImage(): ImageContainer =
    suspendCancellableCoroutine { continuation ->
        MainScope().launch {
            NSLog("pickSystemImage MainScope().launch")
            val imagePicker = UIImagePickerController()
            NSLog("pickSystemImage 1")
            // present and handle
        }
    }

the problem is that initializing UIImagePickerController takes huge amount of time - around 6 secs, every time.

2021-01-24 21:56:42.439651+0700 Well[3450:1028035] pickSystemImage MainScope().launch
2021-01-24 21:56:48.593539+0700 Well[3450:1028035] pickSystemImage 1

I’ve tried reproducing this in a test project, and there it works fine.
I’ve tried switching outer scope, as well as creating scope with main context instead of MainScope, or just without switch to an other scope..
I’m out of the ideas where to look for a solution

[louiscad]

This is not the right way to use suspendCancellableCoroutine at all FYI (you can refere to its doc).
You are probably looking for Dispatchers.Default { } since it looks like you have a blocking call.

[Philip Dukhov]

I wanna to return a picked image as a result of this suspend function, that’s why suspendCancellableCoroutine is used here

[Philip Dukhov]

MainScope needed here because on the next step I need to present the VC, and it can only be done on main thread

[Philip Dukhov]

I’ve tried moving it out of the suspendCancellableCoroutine

suspend fun pickSystemImage(): ImageContainer =
    Dispatchers.Main {
        NSLog("pickSystemImage")
        val imagePicker = UIImagePickerController()
        NSLog("imagePicker created")
        //…
    }

Result is the same - 6 seconds to initiate the picker

[louiscad]

That's probably related to UIImagePickerController() itself, or something else in your app keeping the main thread/loop busy. Did you Google UIImagePickerController?

[Philip Dukhov]

oh looks like the reason is a connected debugger, without debug it works fine. my mistake was not exploring this direction, thanks!