<@UHAJKUSTU> I have a Flow<PagingData<T>>, now I w...

# decompose

[Vaibhav Jaiswal]

@Arkadii Ivanov I have a Flow<PagingDataT>, now I want each item of this PagingData to be a page in the Pager Navigation
How can i achieve this?

[Arkadii Ivanov]

Sorry, I'm not quite familiar with paging libraries. You might need to subscribe to the paging source and use StackNavigation to append new pages. And also trigger next page loading on scroll.

[Vaibhav Jaiswal]

Thanks, I'll try this out

[Arkadii Ivanov]

This discussion might be helpful as well: https://github.com/arkivanov/Decompose/discussions/462

[Vaibhav Jaiswal]

Thanks a lot, ill try this way

[Vaibhav Jaiswal]

Hi @Arkadii Ivanov I was trying this out
This is how I have created the Pages

val childPages = childPages(
    source = navigation,
    serializer = IdeathonPagesConfig.serializer(),
    childFactory = { config, context ->
        IdeathonPages.Competition(createComponent(config, context))
    }
)

and this how i am adding the pages

val index = if(childPages.value.selectedIndex == -1) 0 else childPages.value.selectedIndex
navigation.navigate {
    it.copy(
        items = it.items + configs,
        selectedIndex = index
    )
}

Ui

Pages(
    pages = pages,
    onPageSelected = component::selectPage,
    modifier = Modifier.fillMaxSize().padding(innerPadding),
    scrollAnimation = PagesScrollAnimation.Default,
){ _, page ->
    CompetitionPage(component = page.component)
}

But i am getting index error
> java.lang.IndexOutOfBoundsException: Index -1, size 3
What am i doing wrong?

[Vaibhav Jaiswal]

Stack Trace -> https://pastebin.com/m1s1mQW1

[Vaibhav Jaiswal]

if I add this before Pages, it works

if(selectedPage == -1) return@Scaffold

[Arkadii Ivanov]

What version of Decompose you are using?

[Vaibhav Jaiswal]

3.0.0

[Arkadii Ivanov]

Interesting! This actually might be a bug in HorizontalPager. I will take a look.

[Arkadii Ivanov]

There are multiple similar issues reported previously but already fixed: https://issuetracker.google.com/issues?q=HorizontalPager%20indexoutofboundsexception%20

You may also try different versions of Compose.

[Vaibhav Jaiswal]

Oh i see
Using that If check wont be causing any issue if I'm not wrong

[Arkadii Ivanov]

Yeah, but I think ideally it should work regardless.

[Arkadii Ivanov]

I will try adding more tests and see how it works.

[Vaibhav Jaiswal]

Thanks

I'm already on CMP 1.6.2, not sure when the fix will be released

[Vaibhav Jaiswal]

Seems to be fixed in 1.7.0

[Arkadii Ivanov]

Wow, thanks for letting me know!

[Vaibhav Jaiswal]

The duplicate issue link in the last comment is the fix, If i'm not wrong
says fixed in 1.7.0

[Arkadii Ivanov]

I will check, thanks.

[Arkadii Ivanov]

I could reproduce the issue without Decompose. It looks like HorizontalPager doesn't like the initial index -1, but works if the initial index is 0. Could you please try setting the following argument for your childPages?

initialPages = { Pages(items = emptyList(), selectedIndex = 0) },