I applied `horizontalScroll` modifier to the `and...

# compose-wear

[Yingding Wang]

I applied horizontalScroll modifier to the androidx.wear.compose.material.dialog.Alert and got an IllegalArgumentException
It appears to me, horizontalScroll modifier applied on the parent composable of a ScalingLazyColumn will raise the IllegalArgumentException, what is the reason for that?
On the contrary, the horizontalScroll modifier applied on the child composable in the item of SLC is fine.

[John Nichol]

Code sample?

[John Nichol]

@Steve Bower [G]

[Yingding Wang]

The composable code is at
https://github.com/yingding/hScrollSLC/blob/main/app/src/main/java/com/example/android/wearable/composeforwearos/MainActivity.kt#L56

The repo can be downloaded from
https://github.com/yingding/hScrollSLC,

please switch

val hasChildSLC = false

to

val hasChildSLC = true

and see the different effects.

[stevebower]

Hi - please could you explain what you're trying to achieve with the Box containing both a ScalingLazyColumn and an Alert? The expected model for using Alert is as content for a Dialog, where the Dialog becomes modal when shown and can either be swiped away or dismissed with a click on one of the Buttons/Chips displayed in the Alert. See AlertDialogSample here, where we have a Box showing either a Chip or an alert, controlled by the showDialog boolean - https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:wear/com[…]a/androidx/wear/compose/material/samples/DialogSample.kt;l=58

[Yingding Wang]

@stevebower I see your point of the Alert which is not Intended for horizontalScroll modifier.
What I would like to do is something like a horizontal scrollable calendar or heart rate graphic with multiple scrollable column. I prototyped with a horizontal scrollable Box and ScalingLazyColumn inside the Box. It doesn’t seem to compile. Now I switched to the implementation with a ScalingLazyColumn with multiple horizontalScroll graphic inside.

I am just curious whether it is technically feasible to do a horizontalScroll and then use multiple SLC for vertical Scrolling in general.

[stevebower]

It is technically feasible to do it - you could use the Accompanist HorizontalPager to handle the horizontal scrolling between pages and then put one SLC on each pages. However, I don't think having both horizontal and vertical scrolling on a page is recommended. For a start, additional vertical content conflicts with having a page indicator (like HorizontalPageIndicator).

[Yingding Wang]

I see, i thought of using multiple horizontal page, then i need to chunk the graphics either way.
Is it possible to do something about the Illegal ArgumentException when SLC is wrapped inside a parent composable with horizontalScroll , it is sometimes difficult to find out which composable contains SLC.
Can SLC just ignore the horizontalScroll conflict, and print a Warning instead of raise an exception? Does this make sense?

[stevebower]

Please can you post a snippet of code that reproduces the IllegalArgumentException?

[Yingding Wang]

@stevebower Here is the repository for the IllegalArgumentException https://github.com/yingding/hScrollSLC
Basically, something like this while composition will trigger the IllegalArgumentException on an Emulator.

Box(
            modifier = Modifier.horizontalScroll(horizontalScrollState), // doesn't work
        ) {
                ScalingLazyColumn {
                    item {
                        Text("hi")
                    }
               }
        }

[stevebower]

I've raised a bug for us to take a look at this next week.