Hardened vertical scrollbar modifiers in order to prevent possible crash when sceen is rotated

This commit is contained in:
Juha Heinanen
2026-03-09 03:52:09 +02:00
parent 5ef800f321
commit afea8456c4

View File

@ -178,15 +178,30 @@ object CustomElements {
): Modifier {
val alpha by animateFloatAsState(
targetValue = if(state.isScrollInProgress || alwaysShow) 1f else 0f,
animationSpec = tween(400, delayMillis = if(state.isScrollInProgress) 0 else 700)
animationSpec = tween(400, delayMillis = if(state.isScrollInProgress) 0 else 700),
label = "scrollbarAlpha"
)
return this then Modifier.drawWithContent {
drawContent()
val viewHeight = state.viewportSize.toFloat()
if (viewHeight <= 0f) return@drawWithContent // Safety check for zero height
val contentHeight = state.maxValue + viewHeight
val scrollbarHeight = (viewHeight * (viewHeight / contentHeight )).coerceIn(10.dp.toPx() .. viewHeight)
val minHeight = 10.dp.toPx()
// Ensure the 'max' of coerceIn is at least as large as 'min'
val scrollbarHeight = (viewHeight * (viewHeight / contentHeight))
.coerceIn(minHeight.coerceAtMost(viewHeight) .. viewHeight)
val variableZone = viewHeight - scrollbarHeight
val scrollbarOffsetY = (state.value.toFloat() / state.maxValue) * variableZone
// Prevent division by zero if maxValue is 0 (no scrolling needed)
val scrollbarOffsetY = if (state.maxValue > 0)
(state.value.toFloat() / state.maxValue) * variableZone
else
0f
drawRoundRect(
cornerRadius = CornerRadius(scrollbarWidth.toPx() / 2, scrollbarWidth.toPx() / 2),
color = color,
@ -206,23 +221,35 @@ object CustomElements {
): Modifier {
val alpha by animateFloatAsState(
targetValue = if (state.isScrollInProgress || alwaysShow) 1f else 0f,
animationSpec = tween(durationMillis = if (state.isScrollInProgress) 150 else 500)
animationSpec = tween(durationMillis = if (state.isScrollInProgress) 150 else 500),
label = "lazyScrollbarAlpha"
)
return drawWithContent {
return this.drawWithContent {
drawContent()
val firstVisibleElementIndex = state.layoutInfo.visibleItemsInfo.firstOrNull()?.index
val needDrawScrollbar = state.isScrollInProgress || alpha > 0.0f
if (needDrawScrollbar && firstVisibleElementIndex != null) {
val elementHeight = this.size.height / state.layoutInfo.totalItemsCount
val scrollbarOffsetY = firstVisibleElementIndex * elementHeight
val scrollbarHeight = state.layoutInfo.visibleItemsInfo.size * elementHeight
drawRoundRect(
cornerRadius = CornerRadius(width.toPx() / 2, width.toPx() / 2),
color = color,
topLeft = Offset(this.size.width - width.toPx(), scrollbarOffsetY),
size = Size(width.toPx(), scrollbarHeight),
alpha = alpha
)
val totalItems = state.layoutInfo.totalItemsCount
val visibleItemsInfo = state.layoutInfo.visibleItemsInfo
// Check if there are items and if they actually exceed the viewport
if (totalItems > 0 && visibleItemsInfo.isNotEmpty()) {
val firstVisibleElementIndex = visibleItemsInfo.first().index
val needDrawScrollbar = state.isScrollInProgress || alpha > 0.0f
if (needDrawScrollbar) {
val elementHeight = this.size.height / totalItems
val scrollbarOffsetY = firstVisibleElementIndex * elementHeight
val scrollbarHeight = visibleItemsInfo.size * elementHeight
// Only draw if the scrollbar is actually smaller than the track
if (scrollbarHeight < this.size.height)
drawRoundRect(
cornerRadius = CornerRadius(width.toPx() / 2, width.toPx() / 2),
color = color,
topLeft = Offset(this.size.width - width.toPx(), scrollbarOffsetY),
size = Size(width.toPx(), scrollbarHeight),
alpha = alpha
)
}
}
}
}