mirror of
https://github.com/null2264/yokai.git
synced 2025-06-21 02:34:39 +00:00
style: Scrollbar
And add fast scroller component for later
This commit is contained in:
parent
f7e5abba59
commit
e554513392
GPG key ID:
BA64F8B60AF3EFB6
3 changed files with 699 additions and 1 deletions
|
|
@ -29,6 +29,7 @@ import yokai.presentation.component.Gap
|
|||
import yokai.presentation.component.preference.Preference
|
||||
import yokai.presentation.component.preference.PreferenceItem
|
||||
import yokai.presentation.component.preference.widget.PreferenceGroupHeader
|
||||
import yokai.presentation.core.drawVerticalScrollbar
|
||||
import yokai.presentation.core.enterAlwaysCollapsedScrollBehavior
|
||||
|
||||
@Composable
|
||||
|
|
@ -106,7 +107,7 @@ fun PreferenceScreen(
|
|||
}
|
||||
|
||||
LazyColumn(
|
||||
modifier = modifier,
|
||||
modifier = modifier.drawVerticalScrollbar(listState),
|
||||
contentPadding = contentPadding,
|
||||
state = listState
|
||||
) {
|
||||
|
|
|
|||
|
|
@ -0,0 +1,249 @@
|
|||
package yokai.presentation.core
|
||||
|
||||
import android.view.ViewConfiguration
|
||||
import androidx.compose.animation.core.Animatable
|
||||
import androidx.compose.animation.core.tween
|
||||
import androidx.compose.foundation.gestures.Orientation
|
||||
import androidx.compose.foundation.layout.fillMaxWidth
|
||||
import androidx.compose.foundation.layout.padding
|
||||
import androidx.compose.foundation.lazy.LazyColumn
|
||||
import androidx.compose.foundation.lazy.LazyListState
|
||||
import androidx.compose.foundation.lazy.LazyRow
|
||||
import androidx.compose.foundation.lazy.rememberLazyListState
|
||||
import androidx.compose.material3.MaterialTheme
|
||||
import androidx.compose.material3.Text
|
||||
import androidx.compose.runtime.Composable
|
||||
import androidx.compose.runtime.LaunchedEffect
|
||||
import androidx.compose.runtime.remember
|
||||
import androidx.compose.ui.Modifier
|
||||
import androidx.compose.ui.composed
|
||||
import androidx.compose.ui.draw.drawWithContent
|
||||
import androidx.compose.ui.geometry.Offset
|
||||
import androidx.compose.ui.geometry.Size
|
||||
import androidx.compose.ui.graphics.Color
|
||||
import androidx.compose.ui.graphics.drawscope.ContentDrawScope
|
||||
import androidx.compose.ui.graphics.drawscope.DrawScope
|
||||
import androidx.compose.ui.input.nestedscroll.NestedScrollConnection
|
||||
import androidx.compose.ui.input.nestedscroll.NestedScrollSource
|
||||
import androidx.compose.ui.input.nestedscroll.nestedScroll
|
||||
import androidx.compose.ui.platform.LocalContext
|
||||
import androidx.compose.ui.platform.LocalLayoutDirection
|
||||
import androidx.compose.ui.tooling.preview.Preview
|
||||
import androidx.compose.ui.unit.LayoutDirection
|
||||
import androidx.compose.ui.unit.dp
|
||||
import androidx.compose.ui.util.fastFirstOrNull
|
||||
import androidx.compose.ui.util.fastSumBy
|
||||
import kotlinx.coroutines.channels.BufferOverflow
|
||||
import kotlinx.coroutines.flow.MutableSharedFlow
|
||||
import kotlinx.coroutines.flow.collectLatest
|
||||
import kotlinx.coroutines.flow.sample
|
||||
import yokai.presentation.core.components.Scroller.STICKY_HEADER_KEY_PREFIX
|
||||
|
||||
/**
|
||||
* Draws horizontal scrollbar to a LazyList.
|
||||
*
|
||||
* Set key with [STICKY_HEADER_KEY_PREFIX] prefix to any sticky header item in the list.
|
||||
*/
|
||||
fun Modifier.drawHorizontalScrollbar(
|
||||
state: LazyListState,
|
||||
reverseScrolling: Boolean = false,
|
||||
// The amount of offset the scrollbar position towards the top of the layout
|
||||
positionOffsetPx: Float = 0f,
|
||||
): Modifier = drawScrollbar(state, Orientation.Horizontal, reverseScrolling, positionOffsetPx)
|
||||
|
||||
/**
|
||||
* Draws vertical scrollbar to a LazyList.
|
||||
*
|
||||
* Set key with [STICKY_HEADER_KEY_PREFIX] prefix to any sticky header item in the list.
|
||||
*/
|
||||
fun Modifier.drawVerticalScrollbar(
|
||||
state: LazyListState,
|
||||
reverseScrolling: Boolean = false,
|
||||
// The amount of offset the scrollbar position towards the start of the layout
|
||||
positionOffsetPx: Float = 0f,
|
||||
): Modifier = drawScrollbar(state, Orientation.Vertical, reverseScrolling, positionOffsetPx)
|
||||
|
||||
private fun Modifier.drawScrollbar(
|
||||
state: LazyListState,
|
||||
orientation: Orientation,
|
||||
reverseScrolling: Boolean,
|
||||
positionOffset: Float,
|
||||
): Modifier = drawScrollbar(
|
||||
orientation,
|
||||
reverseScrolling,
|
||||
) { reverseDirection, atEnd, thickness, color, alpha ->
|
||||
val layoutInfo = state.layoutInfo
|
||||
val viewportSize = if (orientation == Orientation.Horizontal) {
|
||||
layoutInfo.viewportSize.width
|
||||
} else {
|
||||
layoutInfo.viewportSize.height
|
||||
} - layoutInfo.beforeContentPadding - layoutInfo.afterContentPadding
|
||||
val items = layoutInfo.visibleItemsInfo
|
||||
val itemsSize = items.fastSumBy { it.size }
|
||||
val showScrollbar = items.size < layoutInfo.totalItemsCount || itemsSize > viewportSize
|
||||
val estimatedItemSize = if (items.isEmpty()) 0f else itemsSize.toFloat() / items.size
|
||||
val totalSize = estimatedItemSize * layoutInfo.totalItemsCount
|
||||
val thumbSize = viewportSize / totalSize * viewportSize
|
||||
val startOffset = if (items.isEmpty()) {
|
||||
0f
|
||||
} else {
|
||||
items
|
||||
.fastFirstOrNull { (it.key as? String)?.startsWith(STICKY_HEADER_KEY_PREFIX)?.not() ?: true }
|
||||
?.run {
|
||||
val startPadding = if (reverseDirection) {
|
||||
layoutInfo.afterContentPadding
|
||||
} else {
|
||||
layoutInfo.beforeContentPadding
|
||||
}
|
||||
startPadding + ((estimatedItemSize * index - offset) / totalSize * viewportSize)
|
||||
} ?: 0f
|
||||
}
|
||||
val drawScrollbar = onDrawScrollbar(
|
||||
orientation, reverseDirection, atEnd, showScrollbar,
|
||||
thickness, color, alpha, thumbSize, startOffset, positionOffset,
|
||||
)
|
||||
drawContent()
|
||||
drawScrollbar()
|
||||
}
|
||||
|
||||
private fun ContentDrawScope.onDrawScrollbar(
|
||||
orientation: Orientation,
|
||||
reverseDirection: Boolean,
|
||||
atEnd: Boolean,
|
||||
showScrollbar: Boolean,
|
||||
thickness: Float,
|
||||
color: Color,
|
||||
alpha: () -> Float,
|
||||
thumbSize: Float,
|
||||
scrollOffset: Float,
|
||||
positionOffset: Float,
|
||||
): DrawScope.() -> Unit {
|
||||
val topLeft = if (orientation == Orientation.Horizontal) {
|
||||
Offset(
|
||||
if (reverseDirection) size.width - scrollOffset - thumbSize else scrollOffset,
|
||||
if (atEnd) size.height - positionOffset - thickness else positionOffset,
|
||||
)
|
||||
} else {
|
||||
Offset(
|
||||
if (atEnd) size.width - positionOffset - thickness else positionOffset,
|
||||
if (reverseDirection) size.height - scrollOffset - thumbSize else scrollOffset,
|
||||
)
|
||||
}
|
||||
val size = if (orientation == Orientation.Horizontal) {
|
||||
Size(thumbSize, thickness)
|
||||
} else {
|
||||
Size(thickness, thumbSize)
|
||||
}
|
||||
|
||||
return {
|
||||
if (showScrollbar) {
|
||||
drawRect(
|
||||
color = color,
|
||||
topLeft = topLeft,
|
||||
size = size,
|
||||
alpha = alpha(),
|
||||
)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
private fun Modifier.drawScrollbar(
|
||||
orientation: Orientation,
|
||||
reverseScrolling: Boolean,
|
||||
onDraw: ContentDrawScope.(
|
||||
reverseDirection: Boolean,
|
||||
atEnd: Boolean,
|
||||
thickness: Float,
|
||||
color: Color,
|
||||
alpha: () -> Float,
|
||||
) -> Unit,
|
||||
): Modifier = composed {
|
||||
val scrolled = remember {
|
||||
MutableSharedFlow<Unit>(
|
||||
extraBufferCapacity = 1,
|
||||
onBufferOverflow = BufferOverflow.DROP_OLDEST,
|
||||
)
|
||||
}
|
||||
val nestedScrollConnection = remember(orientation, scrolled) {
|
||||
object : NestedScrollConnection {
|
||||
override fun onPostScroll(
|
||||
consumed: Offset,
|
||||
available: Offset,
|
||||
source: NestedScrollSource,
|
||||
): Offset {
|
||||
val delta = if (orientation == Orientation.Horizontal) consumed.x else consumed.y
|
||||
if (delta != 0f) scrolled.tryEmit(Unit)
|
||||
return Offset.Zero
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
val alpha = remember { Animatable(0f) }
|
||||
LaunchedEffect(scrolled, alpha) {
|
||||
scrolled
|
||||
.sample(100)
|
||||
.collectLatest {
|
||||
alpha.snapTo(1f)
|
||||
alpha.animateTo(0f, animationSpec = FadeOutAnimationSpec)
|
||||
}
|
||||
}
|
||||
|
||||
val isLtr = LocalLayoutDirection.current == LayoutDirection.Ltr
|
||||
val reverseDirection = if (orientation == Orientation.Horizontal) {
|
||||
if (isLtr) reverseScrolling else !reverseScrolling
|
||||
} else {
|
||||
reverseScrolling
|
||||
}
|
||||
val atEnd = if (orientation == Orientation.Vertical) isLtr else true
|
||||
|
||||
val context = LocalContext.current
|
||||
val thickness = remember { ViewConfiguration.get(context).scaledScrollBarSize.toFloat() }
|
||||
val color = MaterialTheme.colorScheme.onSurface.copy(alpha = 0.364f)
|
||||
Modifier
|
||||
.nestedScroll(nestedScrollConnection)
|
||||
.drawWithContent {
|
||||
onDraw(reverseDirection, atEnd, thickness, color, alpha::value)
|
||||
}
|
||||
}
|
||||
|
||||
private val FadeOutAnimationSpec = tween<Float>(
|
||||
durationMillis = ViewConfiguration.getScrollBarFadeDuration(),
|
||||
delayMillis = ViewConfiguration.getScrollDefaultDelay(),
|
||||
)
|
||||
|
||||
@Preview(widthDp = 400, heightDp = 400, showBackground = true)
|
||||
@Composable
|
||||
fun LazyListScrollbarPreview() {
|
||||
val state = rememberLazyListState()
|
||||
LazyColumn(
|
||||
modifier = Modifier.drawVerticalScrollbar(state),
|
||||
state = state,
|
||||
) {
|
||||
items(50) {
|
||||
Text(
|
||||
text = "Item ${it + 1}",
|
||||
modifier = Modifier
|
||||
.fillMaxWidth()
|
||||
.padding(16.dp),
|
||||
)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
@Preview(widthDp = 400, showBackground = true)
|
||||
@Composable
|
||||
fun LazyListHorizontalScrollbarPreview() {
|
||||
val state = rememberLazyListState()
|
||||
LazyRow(
|
||||
modifier = Modifier.drawHorizontalScrollbar(state),
|
||||
state = state,
|
||||
) {
|
||||
items(50) {
|
||||
Text(
|
||||
text = (it + 1).toString(),
|
||||
modifier = Modifier
|
||||
.padding(horizontal = 8.dp, vertical = 16.dp),
|
||||
)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,448 @@
|
|||
package yokai.presentation.core.components
|
||||
|
||||
import android.view.ViewConfiguration
|
||||
import androidx.compose.animation.core.Animatable
|
||||
import androidx.compose.animation.core.tween
|
||||
import androidx.compose.foundation.background
|
||||
import androidx.compose.foundation.gestures.Orientation
|
||||
import androidx.compose.foundation.gestures.draggable
|
||||
import androidx.compose.foundation.gestures.rememberDraggableState
|
||||
import androidx.compose.foundation.interaction.MutableInteractionSource
|
||||
import androidx.compose.foundation.interaction.collectIsDraggedAsState
|
||||
import androidx.compose.foundation.layout.Arrangement
|
||||
import androidx.compose.foundation.layout.Box
|
||||
import androidx.compose.foundation.layout.PaddingValues
|
||||
import androidx.compose.foundation.layout.calculateEndPadding
|
||||
import androidx.compose.foundation.layout.calculateStartPadding
|
||||
import androidx.compose.foundation.layout.height
|
||||
import androidx.compose.foundation.layout.offset
|
||||
import androidx.compose.foundation.layout.padding
|
||||
import androidx.compose.foundation.layout.width
|
||||
import androidx.compose.foundation.lazy.LazyListItemInfo
|
||||
import androidx.compose.foundation.lazy.LazyListState
|
||||
import androidx.compose.foundation.lazy.grid.GridCells
|
||||
import androidx.compose.foundation.lazy.grid.LazyGridState
|
||||
import androidx.compose.foundation.shape.RoundedCornerShape
|
||||
import androidx.compose.foundation.systemGestureExclusion
|
||||
import androidx.compose.material3.MaterialTheme
|
||||
import androidx.compose.runtime.Composable
|
||||
import androidx.compose.runtime.LaunchedEffect
|
||||
import androidx.compose.runtime.getValue
|
||||
import androidx.compose.runtime.mutableFloatStateOf
|
||||
import androidx.compose.runtime.remember
|
||||
import androidx.compose.runtime.setValue
|
||||
import androidx.compose.ui.Modifier
|
||||
import androidx.compose.ui.draw.alpha
|
||||
import androidx.compose.ui.graphics.Color
|
||||
import androidx.compose.ui.layout.SubcomposeLayout
|
||||
import androidx.compose.ui.platform.LocalDensity
|
||||
import androidx.compose.ui.unit.Constraints
|
||||
import androidx.compose.ui.unit.Density
|
||||
import androidx.compose.ui.unit.Dp
|
||||
import androidx.compose.ui.unit.IntOffset
|
||||
import androidx.compose.ui.unit.LayoutDirection
|
||||
import androidx.compose.ui.unit.dp
|
||||
import androidx.compose.ui.util.fastFirstOrNull
|
||||
import androidx.compose.ui.util.fastForEach
|
||||
import androidx.compose.ui.util.fastMaxBy
|
||||
import kotlin.math.abs
|
||||
import kotlin.math.max
|
||||
import kotlin.math.min
|
||||
import kotlin.math.roundToInt
|
||||
import kotlinx.coroutines.channels.BufferOverflow
|
||||
import kotlinx.coroutines.flow.MutableSharedFlow
|
||||
import kotlinx.coroutines.flow.collectLatest
|
||||
import kotlinx.coroutines.flow.sample
|
||||
import yokai.presentation.core.components.Scroller.STICKY_HEADER_KEY_PREFIX
|
||||
|
||||
/**
|
||||
* Draws vertical fast scroller to a lazy list
|
||||
*
|
||||
* Set key with [STICKY_HEADER_KEY_PREFIX] prefix to any sticky header item in the list.
|
||||
*/
|
||||
@Composable
|
||||
fun VerticalFastScroller(
|
||||
listState: LazyListState,
|
||||
modifier: Modifier = Modifier,
|
||||
thumbAllowed: () -> Boolean = { true },
|
||||
thumbColor: Color = MaterialTheme.colorScheme.primary,
|
||||
topContentPadding: Dp = Dp.Hairline,
|
||||
bottomContentPadding: Dp = Dp.Hairline,
|
||||
endContentPadding: Dp = Dp.Hairline,
|
||||
content: @Composable () -> Unit,
|
||||
) {
|
||||
SubcomposeLayout(modifier = modifier) { constraints ->
|
||||
val contentPlaceable = subcompose("content", content).map { it.measure(constraints) }
|
||||
val contentHeight = contentPlaceable.fastMaxBy { it.height }?.height ?: 0
|
||||
val contentWidth = contentPlaceable.fastMaxBy { it.width }?.width ?: 0
|
||||
|
||||
val scrollerConstraints = constraints.copy(minWidth = 0, minHeight = 0)
|
||||
val scrollerPlaceable = subcompose("scroller") {
|
||||
val layoutInfo = listState.layoutInfo
|
||||
val showScroller = layoutInfo.visibleItemsInfo.size < layoutInfo.totalItemsCount
|
||||
if (!showScroller) return@subcompose
|
||||
|
||||
val thumbTopPadding = with(LocalDensity.current) { topContentPadding.toPx() }
|
||||
var thumbOffsetY by remember(thumbTopPadding) { mutableFloatStateOf(thumbTopPadding) }
|
||||
|
||||
val dragInteractionSource = remember { MutableInteractionSource() }
|
||||
val isThumbDragged by dragInteractionSource.collectIsDraggedAsState()
|
||||
val scrolled = remember {
|
||||
MutableSharedFlow<Unit>(
|
||||
extraBufferCapacity = 1,
|
||||
onBufferOverflow = BufferOverflow.DROP_OLDEST,
|
||||
)
|
||||
}
|
||||
|
||||
val thumbBottomPadding = with(LocalDensity.current) { bottomContentPadding.toPx() }
|
||||
val heightPx = contentHeight.toFloat() -
|
||||
thumbTopPadding -
|
||||
thumbBottomPadding -
|
||||
listState.layoutInfo.afterContentPadding
|
||||
val thumbHeightPx = with(LocalDensity.current) { ThumbLength.toPx() }
|
||||
val trackHeightPx = heightPx - thumbHeightPx
|
||||
|
||||
// When thumb dragged
|
||||
LaunchedEffect(thumbOffsetY) {
|
||||
if (layoutInfo.totalItemsCount == 0 || !isThumbDragged) return@LaunchedEffect
|
||||
val scrollRatio = (thumbOffsetY - thumbTopPadding) / trackHeightPx
|
||||
val scrollItem = layoutInfo.totalItemsCount * scrollRatio
|
||||
val scrollItemRounded = scrollItem.roundToInt()
|
||||
val scrollItemSize = layoutInfo.visibleItemsInfo.find { it.index == scrollItemRounded }?.size ?: 0
|
||||
val scrollItemOffset = scrollItemSize * (scrollItem - scrollItemRounded)
|
||||
listState.scrollToItem(index = scrollItemRounded, scrollOffset = scrollItemOffset.roundToInt())
|
||||
scrolled.tryEmit(Unit)
|
||||
}
|
||||
|
||||
// When list scrolled
|
||||
LaunchedEffect(listState.firstVisibleItemScrollOffset) {
|
||||
if (listState.layoutInfo.totalItemsCount == 0 || isThumbDragged) return@LaunchedEffect
|
||||
val scrollOffset = computeScrollOffset(state = listState)
|
||||
val scrollRange = computeScrollRange(state = listState)
|
||||
val proportion = scrollOffset.toFloat() / (scrollRange.toFloat() - heightPx)
|
||||
thumbOffsetY = trackHeightPx * proportion + thumbTopPadding
|
||||
scrolled.tryEmit(Unit)
|
||||
}
|
||||
|
||||
// Thumb alpha
|
||||
val alpha = remember { Animatable(0f) }
|
||||
val isThumbVisible = alpha.value > 0f
|
||||
LaunchedEffect(scrolled, alpha) {
|
||||
scrolled
|
||||
.sample(100)
|
||||
.collectLatest {
|
||||
if (thumbAllowed()) {
|
||||
alpha.snapTo(1f)
|
||||
alpha.animateTo(0f, animationSpec = FadeOutAnimationSpec)
|
||||
} else {
|
||||
alpha.animateTo(0f, animationSpec = ImmediateFadeOutAnimationSpec)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Box(
|
||||
modifier = Modifier
|
||||
.offset { IntOffset(0, thumbOffsetY.roundToInt()) }
|
||||
.then(
|
||||
// Recompose opts
|
||||
if (isThumbVisible && !listState.isScrollInProgress) {
|
||||
Modifier.draggable(
|
||||
interactionSource = dragInteractionSource,
|
||||
orientation = Orientation.Vertical,
|
||||
state = rememberDraggableState { delta ->
|
||||
val newOffsetY = thumbOffsetY + delta
|
||||
thumbOffsetY = newOffsetY.coerceIn(
|
||||
thumbTopPadding,
|
||||
thumbTopPadding + trackHeightPx,
|
||||
)
|
||||
},
|
||||
)
|
||||
} else {
|
||||
Modifier
|
||||
},
|
||||
)
|
||||
.then(
|
||||
// Exclude thumb from gesture area only when needed
|
||||
if (isThumbVisible && !isThumbDragged && !listState.isScrollInProgress) {
|
||||
Modifier.systemGestureExclusion()
|
||||
} else {
|
||||
Modifier
|
||||
},
|
||||
)
|
||||
.height(ThumbLength)
|
||||
.padding(horizontal = 8.dp)
|
||||
.padding(end = endContentPadding)
|
||||
.width(ThumbThickness)
|
||||
.alpha(alpha.value)
|
||||
.background(color = thumbColor, shape = ThumbShape),
|
||||
)
|
||||
}.map { it.measure(scrollerConstraints) }
|
||||
val scrollerWidth = scrollerPlaceable.fastMaxBy { it.width }?.width ?: 0
|
||||
|
||||
layout(contentWidth, contentHeight) {
|
||||
contentPlaceable.fastForEach {
|
||||
it.place(0, 0)
|
||||
}
|
||||
scrollerPlaceable.fastForEach {
|
||||
it.placeRelative(contentWidth - scrollerWidth, 0)
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
@Composable
|
||||
private fun rememberColumnWidthSums(
|
||||
columns: GridCells,
|
||||
horizontalArrangement: Arrangement.Horizontal,
|
||||
contentPadding: PaddingValues,
|
||||
) = remember<Density.(Constraints) -> List<Int>>(
|
||||
columns,
|
||||
horizontalArrangement,
|
||||
contentPadding,
|
||||
) {
|
||||
{ constraints ->
|
||||
require(constraints.maxWidth != Constraints.Infinity) {
|
||||
"LazyVerticalGrid's width should be bound by parent"
|
||||
}
|
||||
val horizontalPadding = contentPadding.calculateStartPadding(LayoutDirection.Ltr) +
|
||||
contentPadding.calculateEndPadding(LayoutDirection.Ltr)
|
||||
val gridWidth = constraints.maxWidth - horizontalPadding.roundToPx()
|
||||
with(columns) {
|
||||
calculateCrossAxisCellSizes(
|
||||
gridWidth,
|
||||
horizontalArrangement.spacing.roundToPx(),
|
||||
).toMutableList().apply {
|
||||
for (i in 1..<size) {
|
||||
this[i] += this[i - 1]
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
@Composable
|
||||
fun VerticalGridFastScroller(
|
||||
state: LazyGridState,
|
||||
columns: GridCells,
|
||||
arrangement: Arrangement.Horizontal,
|
||||
contentPadding: PaddingValues,
|
||||
modifier: Modifier = Modifier,
|
||||
thumbAllowed: () -> Boolean = { true },
|
||||
thumbColor: Color = MaterialTheme.colorScheme.primary,
|
||||
topContentPadding: Dp = Dp.Hairline,
|
||||
bottomContentPadding: Dp = Dp.Hairline,
|
||||
endContentPadding: Dp = Dp.Hairline,
|
||||
content: @Composable () -> Unit,
|
||||
) {
|
||||
val slotSizesSums = rememberColumnWidthSums(
|
||||
columns = columns,
|
||||
horizontalArrangement = arrangement,
|
||||
contentPadding = contentPadding,
|
||||
)
|
||||
|
||||
SubcomposeLayout(modifier = modifier) { constraints ->
|
||||
val contentPlaceable = subcompose("content", content).map { it.measure(constraints) }
|
||||
val contentHeight = contentPlaceable.fastMaxBy { it.height }?.height ?: 0
|
||||
val contentWidth = contentPlaceable.fastMaxBy { it.width }?.width ?: 0
|
||||
|
||||
val scrollerConstraints = constraints.copy(minWidth = 0, minHeight = 0)
|
||||
val scrollerPlaceable = subcompose("scroller") {
|
||||
val layoutInfo = state.layoutInfo
|
||||
val showScroller = layoutInfo.visibleItemsInfo.size < layoutInfo.totalItemsCount
|
||||
if (!showScroller) return@subcompose
|
||||
val thumbTopPadding = with(LocalDensity.current) { topContentPadding.toPx() }
|
||||
var thumbOffsetY by remember(thumbTopPadding) { mutableFloatStateOf(thumbTopPadding) }
|
||||
|
||||
val dragInteractionSource = remember { MutableInteractionSource() }
|
||||
val isThumbDragged by dragInteractionSource.collectIsDraggedAsState()
|
||||
val scrolled = remember {
|
||||
MutableSharedFlow<Unit>(
|
||||
extraBufferCapacity = 1,
|
||||
onBufferOverflow = BufferOverflow.DROP_OLDEST,
|
||||
)
|
||||
}
|
||||
|
||||
val thumbBottomPadding = with(LocalDensity.current) { bottomContentPadding.toPx() }
|
||||
val heightPx = contentHeight.toFloat() -
|
||||
thumbTopPadding -
|
||||
thumbBottomPadding -
|
||||
state.layoutInfo.afterContentPadding
|
||||
val thumbHeightPx = with(LocalDensity.current) { ThumbLength.toPx() }
|
||||
val trackHeightPx = heightPx - thumbHeightPx
|
||||
|
||||
val columnCount = remember { slotSizesSums(constraints).size }
|
||||
|
||||
// When thumb dragged
|
||||
LaunchedEffect(thumbOffsetY) {
|
||||
if (layoutInfo.totalItemsCount == 0 || !isThumbDragged) return@LaunchedEffect
|
||||
val scrollRatio = (thumbOffsetY - thumbTopPadding) / trackHeightPx
|
||||
val scrollItem = layoutInfo.totalItemsCount * scrollRatio
|
||||
// I can't think of anything else rn but this'll do
|
||||
val scrollItemWhole = scrollItem.toInt()
|
||||
val columnNum = ((scrollItemWhole + 1) % columnCount).takeIf { it != 0 } ?: columnCount
|
||||
val scrollItemFraction = if (scrollItemWhole == 0) scrollItem else scrollItem % scrollItemWhole
|
||||
val offsetPerItem = 1f / columnCount
|
||||
val offsetRatio = (offsetPerItem * scrollItemFraction) + (offsetPerItem * (columnNum - 1))
|
||||
|
||||
// TODO: Sometimes item height is not available when scrolling up
|
||||
val scrollItemSize = (1..columnCount).maxOf { num ->
|
||||
val actualIndex = if (num != columnNum) {
|
||||
scrollItemWhole + num - columnCount
|
||||
} else {
|
||||
scrollItemWhole
|
||||
}
|
||||
layoutInfo.visibleItemsInfo.find { it.index == actualIndex }?.size?.height ?: 0
|
||||
}
|
||||
val scrollItemOffset = scrollItemSize * offsetRatio
|
||||
|
||||
state.scrollToItem(index = scrollItemWhole, scrollOffset = scrollItemOffset.roundToInt())
|
||||
scrolled.tryEmit(Unit)
|
||||
}
|
||||
|
||||
// When list scrolled
|
||||
LaunchedEffect(state.firstVisibleItemScrollOffset) {
|
||||
if (state.layoutInfo.totalItemsCount == 0 || isThumbDragged) return@LaunchedEffect
|
||||
val scrollOffset = computeScrollOffset(state = state)
|
||||
val scrollRange = computeScrollRange(state = state)
|
||||
val proportion = scrollOffset.toFloat() / (scrollRange.toFloat() - heightPx)
|
||||
thumbOffsetY = trackHeightPx * proportion + thumbTopPadding
|
||||
scrolled.tryEmit(Unit)
|
||||
}
|
||||
|
||||
// Thumb alpha
|
||||
val alpha = remember { Animatable(0f) }
|
||||
val isThumbVisible = alpha.value > 0f
|
||||
LaunchedEffect(scrolled, alpha) {
|
||||
scrolled
|
||||
.sample(100)
|
||||
.collectLatest {
|
||||
if (thumbAllowed()) {
|
||||
alpha.snapTo(1f)
|
||||
alpha.animateTo(0f, animationSpec = FadeOutAnimationSpec)
|
||||
} else {
|
||||
alpha.animateTo(0f, animationSpec = ImmediateFadeOutAnimationSpec)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Box(
|
||||
modifier = Modifier
|
||||
.offset { IntOffset(0, thumbOffsetY.roundToInt()) }
|
||||
.then(
|
||||
// Recompose opts
|
||||
if (isThumbVisible && !state.isScrollInProgress) {
|
||||
Modifier.draggable(
|
||||
interactionSource = dragInteractionSource,
|
||||
orientation = Orientation.Vertical,
|
||||
state = rememberDraggableState { delta ->
|
||||
val newOffsetY = thumbOffsetY + delta
|
||||
thumbOffsetY = newOffsetY.coerceIn(
|
||||
thumbTopPadding,
|
||||
thumbTopPadding + trackHeightPx,
|
||||
)
|
||||
},
|
||||
)
|
||||
} else {
|
||||
Modifier
|
||||
},
|
||||
)
|
||||
.then(
|
||||
// Exclude thumb from gesture area only when needed
|
||||
if (isThumbVisible && !isThumbDragged && !state.isScrollInProgress) {
|
||||
Modifier.systemGestureExclusion()
|
||||
} else {
|
||||
Modifier
|
||||
},
|
||||
)
|
||||
.height(ThumbLength)
|
||||
.padding(end = endContentPadding)
|
||||
.width(ThumbThickness)
|
||||
.alpha(alpha.value)
|
||||
.background(color = thumbColor, shape = ThumbShape),
|
||||
)
|
||||
}.map { it.measure(scrollerConstraints) }
|
||||
val scrollerWidth = scrollerPlaceable.fastMaxBy { it.width }?.width ?: 0
|
||||
|
||||
layout(contentWidth, contentHeight) {
|
||||
contentPlaceable.fastForEach {
|
||||
it.place(0, 0)
|
||||
}
|
||||
scrollerPlaceable.fastForEach {
|
||||
it.placeRelative(contentWidth - scrollerWidth, 0)
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
private fun computeScrollOffset(state: LazyGridState): Int {
|
||||
if (state.layoutInfo.totalItemsCount == 0) return 0
|
||||
val visibleItems = state.layoutInfo.visibleItemsInfo
|
||||
val startChild = visibleItems.first()
|
||||
val endChild = visibleItems.last()
|
||||
val minPosition = min(startChild.index, endChild.index)
|
||||
val maxPosition = max(startChild.index, endChild.index)
|
||||
val itemsBefore = minPosition.coerceAtLeast(0)
|
||||
val startDecoratedTop = startChild.offset.y
|
||||
val laidOutArea = abs((endChild.offset.y + endChild.size.height) - startDecoratedTop)
|
||||
val itemRange = abs(minPosition - maxPosition) + 1
|
||||
val avgSizePerRow = laidOutArea.toFloat() / itemRange
|
||||
return (itemsBefore * avgSizePerRow + (0 - startDecoratedTop)).roundToInt()
|
||||
}
|
||||
|
||||
private fun computeScrollRange(state: LazyGridState): Int {
|
||||
if (state.layoutInfo.totalItemsCount == 0) return 0
|
||||
val visibleItems = state.layoutInfo.visibleItemsInfo
|
||||
val startChild = visibleItems.first()
|
||||
val endChild = visibleItems.last()
|
||||
val laidOutArea = (endChild.offset.y + endChild.size.height) - startChild.offset.y
|
||||
val laidOutRange = abs(startChild.index - endChild.index) + 1
|
||||
return (laidOutArea.toFloat() / laidOutRange * state.layoutInfo.totalItemsCount).roundToInt()
|
||||
}
|
||||
|
||||
private fun computeScrollOffset(state: LazyListState): Int {
|
||||
if (state.layoutInfo.totalItemsCount == 0) return 0
|
||||
val visibleItems = state.layoutInfo.visibleItemsInfo
|
||||
val startChild = visibleItems
|
||||
.fastFirstOrNull { (it.key as? String)?.startsWith(STICKY_HEADER_KEY_PREFIX)?.not() ?: true }!!
|
||||
val endChild = visibleItems.last()
|
||||
val minPosition = min(startChild.index, endChild.index)
|
||||
val maxPosition = max(startChild.index, endChild.index)
|
||||
val itemsBefore = minPosition.coerceAtLeast(0)
|
||||
val startDecoratedTop = startChild.top
|
||||
val laidOutArea = abs(endChild.bottom - startDecoratedTop)
|
||||
val itemRange = abs(minPosition - maxPosition) + 1
|
||||
val avgSizePerRow = laidOutArea.toFloat() / itemRange
|
||||
return (itemsBefore * avgSizePerRow + (0 - startDecoratedTop)).roundToInt()
|
||||
}
|
||||
|
||||
private fun computeScrollRange(state: LazyListState): Int {
|
||||
if (state.layoutInfo.totalItemsCount == 0) return 0
|
||||
val visibleItems = state.layoutInfo.visibleItemsInfo
|
||||
val startChild = visibleItems
|
||||
.fastFirstOrNull { (it.key as? String)?.startsWith(STICKY_HEADER_KEY_PREFIX)?.not() ?: true }!!
|
||||
val endChild = visibleItems.last()
|
||||
val laidOutArea = endChild.bottom - startChild.top
|
||||
val laidOutRange = abs(startChild.index - endChild.index) + 1
|
||||
return (laidOutArea.toFloat() / laidOutRange * state.layoutInfo.totalItemsCount).roundToInt()
|
||||
}
|
||||
|
||||
object Scroller {
|
||||
const val STICKY_HEADER_KEY_PREFIX = "sticky:"
|
||||
}
|
||||
|
||||
private val ThumbLength = 48.dp
|
||||
private val ThumbThickness = 12.dp
|
||||
private val ThumbShape = RoundedCornerShape(ThumbThickness / 2)
|
||||
private val FadeOutAnimationSpec = tween<Float>(
|
||||
durationMillis = ViewConfiguration.getScrollBarFadeDuration(),
|
||||
delayMillis = 2000,
|
||||
)
|
||||
private val ImmediateFadeOutAnimationSpec = tween<Float>(
|
||||
durationMillis = ViewConfiguration.getScrollBarFadeDuration(),
|
||||
)
|
||||
|
||||
private val LazyListItemInfo.top: Int
|
||||
get() = offset
|
||||
|
||||
private val LazyListItemInfo.bottom: Int
|
||||
get() = offset + size
|
||||
Loading…
Add table
Add a link
Reference in a new issue