We have the same problem like this one in <stackov...

# compose-android

[gts13]

We have the same problem like this one in stackoverflow. We can't disable buck button in ModalBottomSheet. Any idea?
We already tried the BackHandler and dialog properties:

dialogProperties = DialogProperties(
            usePlatformDefaultWidth = false,
            dismissOnBackPress = false,
            dismissOnClickOutside = false
        )

Any idea? 🙄

[bryankeltonadams]

same issue, not trying to disable back button, but just change it's behavior. Have you found anything?

[Oleksandr Balan]

I have been investigating it a little bit, and as I understand it is not possible as for now.

The underlying implementation uses ModalBottomSheetWindow, which has this code to handle back press:

override fun dispatchKeyEvent(event: KeyEvent): Boolean {
        if (event.keyCode == KeyEvent.KEYCODE_BACK) {
            if (keyDispatcherState == null) {
                return super.dispatchKeyEvent(event)
            }
            if (event.action == KeyEvent.ACTION_DOWN && event.repeatCount == 0) {
                val state = keyDispatcherState
                state?.startTracking(event, this)
                return true
            } else if (event.action == KeyEvent.ACTION_UP) {
                val state = keyDispatcherState
                if (state != null && state.isTracking(event) && !event.isCanceled) {
                    onDismissRequest()
                    return true
                }
            }
        }
        return super.dispatchKeyEvent(event)
    }

So it always handles back button and invokes onDismissRequest , where it does the following:

onDismissRequest = {
            if (sheetState.currentValue == Expanded && sheetState.hasPartiallyExpandedState) {
                scope.launch { sheetState.partialExpand() }
            } else { // Is expanded without collapsed state or is collapsed.
                scope.launch { sheetState.hide() }.invokeOnCompletion { onDismissRequest() }
            }
        },

Thus hides or partially collapses the modal bottom sheet and now there are no customization options 😕

I guess you can give a ⭐ to this issue: https://issuetracker.google.com/issues/278216859

[bryankeltonadams]

Oleksandr, I looked into the file containing the ModalBottomSheet and I speculated the same issue as you described, a lot of this code is internal to this file otherwise it might not be that awful to make a custom ModalBottomSheet Composable that rips out a lot of that backHandling stuff. i.e. fixing the issue ourselves on a per-project level.

[bryankeltonadams]

sorry, not just internal to the file but also internal to the material3.compose package etc.