Merge "Fix pager state after configuration change" into udc-dev

import androidx.compose.foundation.layout.Column

import androidx.compose.foundation.layout.padding

import androidx.compose.foundation.pager.HorizontalPager

import androidx.compose.foundation.pager.rememberPagerState

import androidx.compose.foundation.pager.PagerState

import androidx.compose.material3.TabRow

import androidx.compose.runtime.Composable

import androidx.compose.runtime.LaunchedEffect

import androidx.compose.runtime.SideEffect

import androidx.compose.runtime.State

import androidx.compose.runtime.getValue

import androidx.compose.runtime.mutableStateOf

import androidx.compose.runtime.remember

import androidx.compose.runtime.rememberCoroutineScope

import androidx.compose.runtime.saveable.rememberSaveable

import androidx.compose.runtime.setValue

import androidx.compose.ui.Modifier

import androidx.compose.ui.graphics.Color

import androidx.compose.ui.platform.LocalConfiguration

import com.android.settingslib.spa.framework.theme.SettingsDimension

import kotlin.math.absoluteValue

import kotlinx.coroutines.launch

    Column {

        val coroutineScope = rememberCoroutineScope()

        val pagerState = rememberPagerState()

        val pagerState by rememberPageStateFixed()

        TabRow(

            selectedTabIndex = pagerState.currentPage,

        }

    }

}

/**

 * Gets the state of [PagerState].

 *

 * This is a work around.

 *

 * TODO: Remove this and replace with rememberPageState() after the Compose Foundation 1.5.0-alpha04

 *       updated in the platform.

 */

@Composable

@OptIn(ExperimentalFoundationApi::class)

private fun rememberPageStateFixed(): State<PagerState> {

    var currentPage by rememberSaveable { mutableStateOf(0) }

    val pagerStateHolder = remember { mutableStateOf(PagerState(currentPage)) }

    LaunchedEffect(LocalConfiguration.current.orientation) {

        // Reset pager state to fix an issue after configuration change.

        // When we declare android:configChanges="orientation" in the manifest, the pager state is

        // in a weird state after configuration change.

        pagerStateHolder.value = PagerState(currentPage)

    }

    SideEffect {

        currentPage = pagerStateHolder.value.currentPage

    }

    return pagerStateHolder

}