While we're on the subject of

ModalBottomSheetLayout

... I have one setup to show a simple

Text

composable in the bottom sheet. But if I try to pass in the text to show, it doesn't work. The bottom sheet doesn't even show up. But if I "hard code" the text, it works fine. Code posted in the thread ...

I don't know if this should work or not but normally I'd do stuff like this using `remember`:

val output = remember(message) { message?.let { stringResource(id = it)} ?: "" }

Can't do that ...

stringResource

is a composable function, and you can't call composables from the block of a

remember

Oh yeah

FWIW, the main

BottomSheetScreen

composable is getting called like this, from the main Acitivity:

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        setContent {
            MaterialTheme {
                    Surface(color = MaterialTheme.colors.background) {

                        var message by remember { mutableStateOf<Int?>(null)}

                        rememberCoroutineScope().launch {
                            delay(3_000)
                            message = R.string.message
                        }
                        BottomSheetScreen(message = message)
                    }

                }
            }
        }
}

Hmmm, what Compose version are you on? I just tried to repro this and it works for me.

beta1 Well that's the thing ... I copied the above to a brand new project and it works there. But in the project that I wrote it in ... it doesn't ...

Hah, fun... When you're saying the bottom sheet doesn't show at all, can you check if the

bottomSheetState.show

call throws a

CancellationException

or completes successfully?

oooh

I've seen some issues with that, but I don't think that's it

yeah, I wouldn't think so, but you never know ... worth a shot

Random thought: Can you try to create a completely new activity, totally barebones, no special flags and host your code in there?

omg

Nice

yeah, good times

So it's cancelled whenever the animation is interrupted

yeah, that "fixes" it

Nice

hehe I guess

ModalBottomSheetLayout

measures the sheet content when laying out everything. The composition of the body content is dependent on the sheet's height. I think what's happening is that the sheet's height changes when the text isn't

null

anymore, causing the body (and the swipeable anchors) to recompose

yeah, that makes sense.

When the anchors are set, it tries to settle into the new correct state (which is still the old one)

Yeah, that's what it boils down to ... There's a race condition down in there somewhere No. Really about the ONLY difference between the 2 activities is that in the one where it is broken, I have added Hilt to the project, so the activity is marked as an

@AndroidEntryPoint

(though I'm not actually having anything injected into it yet).

When you mark the other one as

@AndroidEntryPoint

, can you repro it there?

haven't tried yet, but I will

In any case, file an issue! cc @matvei, look! Somebody encountered the bug I created with the first version of my CL

yeah, I'll file an issue. Trying to get a consistent repoducable version. I hate to file without cause as we've seen, if you just create a new project and put the code it, it's fine.

As an alternative, you can copy your project and strip everything but this composable. If it still doesn't work you have your sample to fill the bug tracker ^^

yeah. At the moment, I'm going the opposite route ... copying the broken project to the new, piece by piece, seeing which piece breaks it. Adding Hilt did not break it.

Some more questions: • You were saying hardcoding the text works. When you hardcode it in your activity (just set a String instead of a resource Int) and pass that down instead, I'm guessing the issue doesn't happen? • Do you have a lot of strings?

I've tried so many things, that I don't remember exactly ... I have tried using pure strings instead of resources and still ran into the problem ... but, at that point I had some additional complexities where there were some Flows and States involved. I may not have done a basic test with pure strings. As for my string resources ... no, there's only like 3 strings in the xml file

@Bradleycorn I had a same issue i think that's because your calling

if (message != null) {
        scope.launch { bottomSheetState.show() }
    }

before setting the bottomSheetState to ModalBottomSheetLayout that's why applying delay works.

@Shakil Karim -- I tried moving the coroutine down AFTER calling the ModalBottomSheetLayout composable, and that had no effect. Also, that wouldn't explain why the code DOES work in a fresh project

@Bradleycorn Ah ok, then it's a separate issue.

Hm, yeah, the question was a bit of a shot in the dark. I was thinking if the retrieval of the

stringResource

could be holding things up

yeah

Yayyy

As mentioned — https://kotlinlang.slack.com/archives/CJLTWPH7S/p1614537608220200?thread_ts=1614530232.195400&cid=CJLTWPH7S Delay the show, e.g.

val scope = rememberCoroutineScope()
val sheetState = rememberModalBottomSheetState()

// in onClick or other callback..
scope.launch {
  delay(1)
  sheetState.show()
}

// alternatively, in composition like in the example in this thread
LaunchedEffect(message) {
  delay(1)
  sheetState.show()
}

Yeah, nasty issue. We need to fix it as some point soon. This is the issue to track: http://issuetracker.google.com/180977981 The crash is not the same, but the idea us the same. The crash is different because we trigger

show

at the different point of time, the one in the bug is more correct. the rule of thumb with coroutine launches is that you should never launch directly from the composition (like in your example above). We have special tools e.g

LaunchedEffect

to launch smth as a side effect, or

DisposableEffect

and

SideEffect

to just call a lambda as a side effects, where you can later do

scope.launch

. Please use those instead of calling launch from the composition.

I have the very same problem, but with a slightly different setup -

NavHost

inside a

ModalBottomSheet

. My solution is a bit more verbose, since I don't really like

delay

s:

/**
 * That is horrible, but I don't have a better option ATM.
 * Please refer to [androidx.compose.material.SwipeableState.processNewAnchors],
 * specifically that part:
 * val targetOffset = newAnchors.getOffset(currentValue)
 * ?: newAnchors.keys.minByOrNull { abs(it - offset.value) }!!
 * try {
 *     animateInternalToOffset(targetOffset, animationSpec)
 * } catch (c: CancellationException) {
 *     // If the animation was interrupted for any reason, snap as a last resort.
 *     snapInternalToOffset(targetOffset)
 * }
 * The problem is that [androidx.compose.material.SwipeableState.processNewAnchors]
 * cancels expanding animation, then I have to re-launch it first after the initial
 * animateInternalToOffset(targetOffset, animationSpec) and then once again after
 * the snapInternalToOffset(targetOffset).
 */
LaunchedEffect(Unit) {
    try {
        modalBottomSheetState.animateTo(ModalBottomSheetValue.Expanded)
    } finally {
        try {
            modalBottomSheetState.animateTo(ModalBottomSheetValue.Expanded)
        } finally {
            modalBottomSheetState.animateTo(ModalBottomSheetValue.Expanded)
        }
    }
}

uuuf, that is quite bad 🙂 Please file a bug, we shouldn't be that "safe" in the swipeable implementation about that

I've already created an issue, here: https://issuetracker.google.com/issues/181593642