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Aug 6, 2025
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example: Use CompositionLocal for PagerState and page change handling #98

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140 changes: 57 additions & 83 deletions example/src/commonMain/kotlin/UITest.kt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -34,10 +34,10 @@ import androidx.compose.foundation.pager.HorizontalPager
import androidx.compose.foundation.pager.PagerState
import androidx.compose.foundation.pager.rememberPagerState
import androidx.compose.runtime.Composable
import androidx.compose.runtime.LaunchedEffect
import androidx.compose.runtime.CompositionLocalProvider
import androidx.compose.runtime.MutableState
import androidx.compose.runtime.compositionLocalOf
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableIntStateOf
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.rememberCoroutineScope
Expand Down Expand Up @@ -136,19 +136,17 @@ data class UIState(
val isWideScreen: Boolean = false,
)

val LocalPagerState = compositionLocalOf<PagerState> { error("No pager state") }
val LocalHandlePageChange = compositionLocalOf<(Int) -> Unit> { error("No handle page change") }

@Composable
fun UITest(
colorMode: MutableState<Int>,
) {
val topAppBarScrollBehaviorList = List(UIConstants.PAGE_COUNT) { MiuixScrollBehavior() }
val pagerState = rememberPagerState(pageCount = { UIConstants.PAGE_COUNT })
val coroutineScope = rememberCoroutineScope()
var selectedPage by remember { mutableIntStateOf(pagerState.currentPage) }
val currentScrollBehavior = topAppBarScrollBehaviorList[selectedPage]

LaunchedEffect(pagerState.settledPage) {
if (selectedPage != pagerState.settledPage) selectedPage = pagerState.settledPage
}
val currentScrollBehavior = topAppBarScrollBehaviorList[pagerState.currentPage]

val navigationItems = remember {
listOf(
Expand All @@ -162,46 +160,44 @@ fun UITest(
val showTopPopup = remember { mutableStateOf(false) }
val windowSize by rememberUpdatedState(getWindowSize())

val onPageSelected: (Int) -> Unit = remember {
val handlePageChange: (Int) -> Unit = remember(pagerState, coroutineScope) {
{ page ->
selectedPage = page
coroutineScope.launch { pagerState.animateScrollToPage(page) }
}
}

BoxWithConstraints(
modifier = Modifier.fillMaxSize()
CompositionLocalProvider(
LocalPagerState provides pagerState,
LocalHandlePageChange provides handlePageChange
) {
val isWideScreen = maxWidth > UIConstants.WIDE_SCREEN_THRESHOLD
uiState = uiState.copy(isWideScreen = isWideScreen)
BoxWithConstraints(
modifier = Modifier.fillMaxSize()
) {
val isWideScreen = maxWidth > UIConstants.WIDE_SCREEN_THRESHOLD
uiState = uiState.copy(isWideScreen = isWideScreen)

if (isWideScreen) {
WideScreenLayout(
selectedPage = selectedPage,
navigationItems = navigationItems,
uiState = uiState,
onUiStateChange = { uiState = it },
onPageSelected = onPageSelected,
showTopPopup = showTopPopup,
pagerState = pagerState,
topAppBarScrollBehaviorList = topAppBarScrollBehaviorList,
currentScrollBehavior = currentScrollBehavior,
windowSize = windowSize,
colorMode = colorMode
)
} else {
CompactScreenLayout(
selectedPage = selectedPage,
navigationItems = navigationItems,
uiState = uiState,
onUiStateChange = { uiState = it },
onPageSelected = onPageSelected,
showTopPopup = showTopPopup,
pagerState = pagerState,
topAppBarScrollBehaviorList = topAppBarScrollBehaviorList,
currentScrollBehavior = currentScrollBehavior,
colorMode = colorMode
)
if (isWideScreen) {
WideScreenLayout(
navigationItems = navigationItems,
uiState = uiState,
onUiStateChange = { uiState = it },
showTopPopup = showTopPopup,
topAppBarScrollBehaviorList = topAppBarScrollBehaviorList,
currentScrollBehavior = currentScrollBehavior,
windowSize = windowSize,
colorMode = colorMode
)
} else {
CompactScreenLayout(
navigationItems = navigationItems,
uiState = uiState,
onUiStateChange = { uiState = it },
showTopPopup = showTopPopup,
topAppBarScrollBehaviorList = topAppBarScrollBehaviorList,
currentScrollBehavior = currentScrollBehavior,
colorMode = colorMode
)
}
}
}

Expand All @@ -221,13 +217,10 @@ fun UITest(

@Composable
private fun WideScreenLayout(
selectedPage: Int,
navigationItems: List<NavigationItem>,
uiState: UIState,
onUiStateChange: (UIState) -> Unit,
onPageSelected: (Int) -> Unit,
showTopPopup: MutableState<Boolean>,
pagerState: PagerState,
topAppBarScrollBehaviorList: List<ScrollBehavior>,
currentScrollBehavior: ScrollBehavior,
windowSize: WindowSize,
Expand All @@ -240,8 +233,6 @@ private fun WideScreenLayout(
Row {
Box(modifier = Modifier.weight(0.4f)) {
WideScreenPanel(
selectedPage = selectedPage,
onPageSelected = onPageSelected,
barScrollBehavior = barScrollBehavior,
uiState = uiState,
windowSize = windowSize,
Expand All @@ -253,12 +244,9 @@ private fun WideScreenLayout(
)
Box(modifier = Modifier.weight(0.6f)) {
WideScreenContent(
selectedPage = selectedPage,
navigationItems = navigationItems,
uiState = uiState,
onPageSelected = onPageSelected,
showTopPopup = showTopPopup,
pagerState = pagerState,
topAppBarScrollBehaviorList = topAppBarScrollBehaviorList,
currentScrollBehavior = currentScrollBehavior,
onUiStateChange = onUiStateChange,
Expand All @@ -271,13 +259,13 @@ private fun WideScreenLayout(

@Composable
private fun WideScreenPanel(
selectedPage: Int,
onPageSelected: (Int) -> Unit,
barScrollBehavior: ScrollBehavior,
uiState: UIState,
windowSize: WindowSize,
layoutDirection: LayoutDirection
) {
val currentPage = LocalPagerState.current.currentPage
val handlePageChange = LocalHandlePageChange.current
Scaffold(
modifier = Modifier
.padding(start = 18.dp, end = 12.dp)
Expand Down Expand Up @@ -312,8 +300,8 @@ private fun WideScreenPanel(
UIConstants.PAGE_TITLES.forEachIndexed { index, title ->
BasicComponent(
title = title,
onClick = { onPageSelected(index) },
holdDownState = selectedPage == index,
onClick = { handlePageChange(index) },
holdDownState = currentPage == index,
)
}
}
Expand All @@ -324,12 +312,9 @@ private fun WideScreenPanel(

@Composable
private fun WideScreenContent(
selectedPage: Int,
navigationItems: List<NavigationItem>,
uiState: UIState,
onPageSelected: (Int) -> Unit,
showTopPopup: MutableState<Boolean>,
pagerState: PagerState,
topAppBarScrollBehaviorList: List<ScrollBehavior>,
currentScrollBehavior: ScrollBehavior,
onUiStateChange: (UIState) -> Unit,
Expand All @@ -346,14 +331,12 @@ private fun WideScreenContent(
exit = fadeOut() + shrinkVertically()
) {
SmallTopAppBar(
title = UIConstants.PAGE_TITLES[selectedPage],
title = UIConstants.PAGE_TITLES[LocalPagerState.current.currentPage],
scrollBehavior = currentScrollBehavior,
actions = {
TopAppBarActions(
selectedPage = selectedPage,
items = navigationItems,
showTopPopup = showTopPopup,
onPageSelected = onPageSelected
showTopPopup = showTopPopup
)
},
defaultWindowInsetsPadding = false,
Expand Down Expand Up @@ -381,7 +364,6 @@ private fun WideScreenContent(
.imePadding()
.windowInsetsPadding(WindowInsets.displayCutout.only(WindowInsetsSides.End))
.windowInsetsPadding(WindowInsets.navigationBars.only(WindowInsetsSides.End)),
pagerState = pagerState,
topAppBarScrollBehaviorList = topAppBarScrollBehaviorList,
padding = PaddingValues(
end = padding.calculateEndPadding(LayoutDirection.Ltr),
Expand All @@ -397,13 +379,10 @@ private fun WideScreenContent(

@Composable
private fun CompactScreenLayout(
selectedPage: Int,
navigationItems: List<NavigationItem>,
uiState: UIState,
onUiStateChange: (UIState) -> Unit,
onPageSelected: (Int) -> Unit,
showTopPopup: MutableState<Boolean>,
pagerState: PagerState,
topAppBarScrollBehaviorList: List<ScrollBehavior>,
currentScrollBehavior: ScrollBehavior,
colorMode: MutableState<Int>
Expand All @@ -421,10 +400,8 @@ private fun CompactScreenLayout(
scrollBehavior = currentScrollBehavior,
actions = {
TopAppBarActions(
selectedPage = selectedPage,
items = navigationItems,
showTopPopup = showTopPopup,
onPageSelected = onPageSelected
showTopPopup = showTopPopup
)
}
)
Expand All @@ -434,8 +411,6 @@ private fun CompactScreenLayout(
NavigationBar(
uiState = uiState,
navigationItems = navigationItems,
selectedPage = selectedPage,
onPageSelected = onPageSelected
)
},
floatingActionButton = {
Expand All @@ -455,7 +430,6 @@ private fun CompactScreenLayout(
.imePadding()
.windowInsetsPadding(WindowInsets.displayCutout.only(WindowInsetsSides.Horizontal))
.windowInsetsPadding(WindowInsets.navigationBars.only(WindowInsetsSides.Horizontal)),
pagerState = pagerState,
topAppBarScrollBehaviorList = topAppBarScrollBehaviorList,
padding = padding,
uiState = uiState,
Expand All @@ -469,9 +443,9 @@ private fun CompactScreenLayout(
private fun NavigationBar(
uiState: UIState,
navigationItems: List<NavigationItem>,
selectedPage: Int,
onPageSelected: (Int) -> Unit
) {
val currentPage = LocalPagerState.current.currentPage
val handlePageChange = LocalHandlePageChange.current
AnimatedVisibility(
visible = uiState.showNavigationBar,
enter = fadeIn() + expandVertically(),
Expand All @@ -484,8 +458,8 @@ private fun NavigationBar(
) {
NavigationBar(
items = navigationItems,
selected = selectedPage,
onClick = onPageSelected
selected = currentPage,
onClick = handlePageChange
)
}
AnimatedVisibility(
Expand All @@ -495,10 +469,11 @@ private fun NavigationBar(
) {
FloatingNavigationBar(
items = navigationItems,
selected = selectedPage,
selected = currentPage,
mode = FloatingNavigationBarDisplayMode.fromInt(uiState.floatingNavigationBarMode).toMode(),
horizontalAlignment = FloatingNavigationBarAlignment.fromInt(uiState.floatingNavigationBarPosition).toAlignment(),
onClick = onPageSelected
horizontalAlignment = FloatingNavigationBarAlignment.fromInt(uiState.floatingNavigationBarPosition)
.toAlignment(),
onClick = handlePageChange
)
}
}
Expand Down Expand Up @@ -617,12 +592,12 @@ private fun FloatingNavigationBarAlignment.toAlignment(): Alignment.Horizontal =

@Composable
private fun TopAppBarActions(
selectedPage: Int,
items: List<NavigationItem>,
showTopPopup: MutableState<Boolean>,
onPageSelected: (Int) -> Unit
) {
val hapticFeedback = LocalHapticFeedback.current
val currentPage = LocalPagerState.current.currentPage
val handlePageChange = LocalHandlePageChange.current

ListPopup(
show = showTopPopup,
Expand All @@ -638,9 +613,9 @@ private fun TopAppBarActions(
DropdownImpl(
text = navigationItem.label,
optionSize = items.size,
isSelected = index == selectedPage,
isSelected = index == currentPage,
onSelectedIndexChange = {
onPageSelected(index)
handlePageChange(index)
hapticFeedback.performHapticFeedback(HapticFeedbackType.Confirm)
showTopPopup.value = false
},
Expand Down Expand Up @@ -668,15 +643,14 @@ private fun TopAppBarActions(
@Composable
fun AppPager(
modifier: Modifier = Modifier,
pagerState: PagerState,
topAppBarScrollBehaviorList: List<ScrollBehavior>,
padding: PaddingValues,
uiState: UIState,
onUiStateChange: (UIState) -> Unit,
colorMode: MutableState<Int>
) {
HorizontalPager(
state = pagerState,
state = LocalPagerState.current,
modifier = modifier,
userScrollEnabled = uiState.enablePageUserScroll,
beyondViewportPageCount = 1,
Expand Down
2 changes: 1 addition & 1 deletion iosApp/iosApp/Info.plist
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@
<key>CFBundleShortVersionString</key>
<string>1.0.4</string>
<key>CFBundleVersion</key>
<string>503</string>
<string>504</string>
<key>LSRequiresIPhoneOS</key>
<true/>
<key>CADisableMinimumFrameDurationOnPhone</key>
Expand Down
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