``` fun PeerMain(updatePage: ((value: PageType) -> Unit)) { Column( modifier = Modifi...

# compose

[calidion]

fun PeerMain(updatePage: ((value: PageType) -> Unit)) {
    Column(
        modifier = Modifier.padding(horizontal = 2.dp),
        verticalArrangement = Arrangement.Center,
        horizontalAlignment = Alignment.CenterHorizontally
    ) {
        var scope = MainApplication.instance!!.coroutineScope;
        var accounts: List<Account>
        scope.launch {
            accounts = MainApplication.instance!!.db.account().getAll()
            if (accounts.isNotEmpty()) {
                accounts.forEach {
                    Text(it.address)
                }
            } else {
                Text(
                    "PeerMain"
                )
            }
        }
    }
}

how to correct this code?

[Chrimaeon]

accounts need to be a state to have the text field updated it state. You can use produceState to call your suspend function.
https://developer.android.com/develop/ui/compose/side-effects#producestate

[Chrimaeon]

I‘d encourage you to start at the beginning and understand how compose and state management works together
https://developer.android.com/develop/ui/compose/state

[calidion]

I always get mind blown by android docs😑

[calidion]

Finally worked out!

val accountList = remember { mutableStateOf<List<Account>>(ArrayList()) }
    LaunchedEffect(Unit) {
        val scope = MainApplication.instance!!.coroutineScope
        scope.launch {
            accountList.value = MainApplication.instance!!.db.account().getAll()
        }
    }

    // If the list is empty, it means that our coroutine has not completed yet and we just want
    // to show our loading component and nothing else. So we return early.
    if (accountList.value.isEmpty()) {
        Text("No Peer Found!")
        return
    } else {
        accountList.value.forEach {
            Text(it.address)
        }
    }

[Chrimaeon]

If you use produceState your code will be more readable.
Also you do not need a scope , the LaunchedEffect is started in a coroutine scope.

[calidion]

produceState doesn't have understandable code snippets for reference.

[calidion]

I extracted code from here: https://github.com/vinaygaba/Learn-Jetpack-Compose-By-Example/blob/master/app/src/[…]a/com/example/jetpackcompose/state/livedata/LiveDataActivity.kt

[calidion]

line 181

[Chrimaeon]

val accountList = produceState(emptyList()) {
            value = MainApplication.instance!!.db.account().getAll()
        }

[calidion]

java.lang.IllegalStateException: Cannot access database on the main thread since it may potentially lock the UI for a long period of time.

[Chrimaeon]

getAll() is a suspend function, right?

[calidion]

yes.

[calidion]

val accountList = remember { mutableStateOf<List<Account>>(ArrayList()) }
    LaunchedEffect(Unit) {
        val scope = MainApplication.instance!!.coroutineScope
        scope.launch {
            accountList.value = MainApplication.instance!!.db.account().getAll()
        }
    }

this snippet works.

[Chrimaeon]

and what database framework do you use? there is a big issue with your suspend function. they should, by definition, be main-safe.

anyway, wrap the suspend function call in a withContext to switch away from the main thread:

val accountList =
            produceState(emptyList<String>()) {
                value =
                    withContext(<http://Dispatchers.IO|Dispatchers.IO>) {
                        MainApplication.instance!!
                            .db
                            .account()
                            .getAll()
                    }
            }

[calidion]

the scope is Dispatchers.IO coroutine.

[Chrimaeon]

yes, but you don’t need a new scope you only need a new context. 😉

[Chrimaeon]

https://www.baeldung.com/kotlin/coroutines-scope-vs-context

[calidion]

✌️*, will look into it later.*