Android 如何更改VerticalScroller'；是否从onScrollPositionChanged回调中选择s滚动位置？
如下面的代码所示，我有一个回调，我想在这里收集Android 如何更改VerticalScroller'；是否从onScrollPositionChanged回调中选择s滚动位置？,android,kotlin,android-jetpack-compose,Android,Kotlin,Android Jetpack Compose,如下面的代码所示，我有一个回调，我想在这里收集VerticalScroller的位置，但如果这样做，VerticalScrollers小部件将不再滚动，因为在VerticalScroller的源代码中，初始回调调用了VerticalScroller的scrollerPosition。无法从要使用该值的回调中访问该值。是否有一种快速方法可以调用滚动位置或使滚动行为继续？（不创建递归“竞争”条件？） 事实上我找到了解决问题的办法。。。（我有时被教导要跳出框框思考…）所以 在我的@Compose函数中
VerticalScrollerVerticalScrollerVerticalScrollerscrollerPosition滚动位置事实上我找到了解决问题的办法。。。（我有时被教导要跳出框框思考…）所以 在我的
@ComposescrollerPositionVerticalScroller滚动程序的逻辑中何时调用onScrolledPostionChanged
。如果在scrollerPosition.position
更改值时调用onScrolledPositionChanged
，则可能会得到递归的“竞争”条件。但显然不是
所以我的变化基本上是这样的：
@Composable
fun StationsScreen(deviceLocation: LocationData, openDrawer: () -> Unit)
{
var scrollPosition = ScrollPosition(0.px,0.px)
var myScrollerPosition = +memo{ ScrollerPosition ()} //<--- make my own scrollerPosition
FlexColumn {
inflexible {
TopAppBar(
title = {Text(text = "Stations")},
navigationIcon = {
VectorImageButton(id = R.drawable.ic_baseline_menu_24) {
openDrawer()
}
}
)
}
inflexible {
Column (
mainAxisSize = LayoutSize.Expand,
crossAxisSize = LayoutSize.Expand
){
LocationWidget(deviceLocation)
}
}
inflexible {
Column(
mainAxisSize = LayoutSize.Expand,
crossAxisSize = LayoutSize.Expand
){
PushWidget(){
deviceLocation.lat++
deviceLocation.lng++
}
}
}
inflexible{
Column(
mainAxisSize = LayoutSize.Expand,
crossAxisSize = LayoutSize.Expand
) {
ScrollPosWidget(scrollPosition = scrollPosition)
}
}
flexible(flex = 1f)
{
VerticalScroller (
scrollerPosition = myScrollerPosition,
onScrollPositionChanged = { px: Px, px1: Px ->
scrollPosition.posX = px
scrollPosition.maxX = px1
myScrollerPosition.value = px //<-- remember to set the new value here
// You can now use the difference of maxX and posX to load
// new items into the list...
}){
Column {
for(i in 0..20) {
HeightSpacer(16.dp)
imageBank.forEach { imageItem: ImageItem ->
Text(text = imageItem.title ?: "<Empty>")
Divider()
}
}
}
}
}
}
}
@Composable
fun LocationWidget(locationData: LocationData){
Surface {
Padding(padding = 8.dp) {
Text(text = "${locationData.lat}, ${locationData.lng}")
}
}
}
@Composable
fun PushWidget(action: () -> Unit){
Surface {
Padding(padding = 8.dp) {
Button(text = "Click Me!", onClick = action)
}
}
}
@Composable
fun ScrollPosWidget(scrollPosition: ScrollPosition){
Surface {
Padding(padding = 8.dp) {
Text(text = "posX=${scrollPosition.posX}, maxX=${scrollPosition.maxX}")
}
}
}
@Composable
趣味站屏幕（设备位置：位置数据，openDrawer:（）->单元）
{
var scrollPosition=scrollPosition（0.px，0.px）
var myScrollerPosition=+memo{ScrollerPosition（）}//
scrollPosition.posX=px
scrollPosition.maxX=px1
myScrollerPosition.value=px//
文本（Text=imageItem.title？：“”）
分隔器（）
}
}
}
}
}
}
}
@组合的
有趣的LocationWidget（locationData:locationData）{
表面{
填充（填充=8.dp）{
Text（Text=“${locationData.lat}，${locationData.lng}”）
}
}
}
@组合的
趣味推送小部件（动作：（）->单位）{
表面{
填充（填充=8.dp）{
按钮（text=“Click Me！”，onClick=action）
}
}
}
@组合的
有趣的ScrollPosWidget（scrollPosition:scrollPosition）{
表面{
填充（填充=8.dp）{
Text（Text=“posX=${scrollPosition.posX}，maxX=${scrollPosition.maxX}”）
}
}
}
RG你能分享这个链接吗？这里有一个compose的每个UI组件的列表。@mudit_sen Thanx供评论，显然找到了一个有效的解决方案（见下面的答案），我将很快在GitHub上发布这个“实验”，并将其链接到这里。在那里，您将看到整个代码。RG@mudit_sen这是该项目的公共链接。随着我对Composable有了更多的经验，它将不断发展。布鲁诺很快解释了一个类似的问题，让垂直卷轴页面化，这可能对他的问题有所帮助。
@Composable
fun VerticalScroller(
scrollerPosition: ScrollerPosition = +memo { ScrollerPosition() },
onScrollPositionChanged: (position: Px, maxPosition: Px) -> Unit = { position, _ ->
scrollerPosition.value = position
},
isScrollable: Boolean = true,
@Children child: @Composable() () -> Unit
) {
Scroller(scrollerPosition, onScrollPositionChanged, true, isScrollable, child)
}
@Composable
fun StationsScreen(deviceLocation: LocationData, openDrawer: () -> Unit)
{
var scrollPosition = ScrollPosition(0.px,0.px)
var myScrollerPosition = +memo{ ScrollerPosition ()} //<--- make my own scrollerPosition
FlexColumn {
inflexible {
TopAppBar(
title = {Text(text = "Stations")},
navigationIcon = {
VectorImageButton(id = R.drawable.ic_baseline_menu_24) {
openDrawer()
}
}
)
}
inflexible {
Column (
mainAxisSize = LayoutSize.Expand,
crossAxisSize = LayoutSize.Expand
){
LocationWidget(deviceLocation)
}
}
inflexible {
Column(
mainAxisSize = LayoutSize.Expand,
crossAxisSize = LayoutSize.Expand
){
PushWidget(){
deviceLocation.lat++
deviceLocation.lng++
}
}
}
inflexible{
Column(
mainAxisSize = LayoutSize.Expand,
crossAxisSize = LayoutSize.Expand
) {
ScrollPosWidget(scrollPosition = scrollPosition)
}
}
flexible(flex = 1f)
{
VerticalScroller (
scrollerPosition = myScrollerPosition,
onScrollPositionChanged = { px: Px, px1: Px ->
scrollPosition.posX = px
scrollPosition.maxX = px1
myScrollerPosition.value = px //<-- remember to set the new value here
// You can now use the difference of maxX and posX to load
// new items into the list...
}){
Column {
for(i in 0..20) {
HeightSpacer(16.dp)
imageBank.forEach { imageItem: ImageItem ->
Text(text = imageItem.title ?: "<Empty>")
Divider()
}
}
}
}
}
}
}
@Composable
fun LocationWidget(locationData: LocationData){
Surface {
Padding(padding = 8.dp) {
Text(text = "${locationData.lat}, ${locationData.lng}")
}
}
}
@Composable
fun PushWidget(action: () -> Unit){
Surface {
Padding(padding = 8.dp) {
Button(text = "Click Me!", onClick = action)
}
}
}
@Composable
fun ScrollPosWidget(scrollPosition: ScrollPosition){
Surface {
Padding(padding = 8.dp) {
Text(text = "posX=${scrollPosition.posX}, maxX=${scrollPosition.maxX}")
}
}
}