我正在使用谷歌伴奏寻呼机在 Android Jetpack Compose 中设计水平寻呼机 (实现“com.google.accompanist:accompanist-pager:0.24.2-alpha”)。 我正确地实现了这个水平寻呼机。但我想将寻呼机的默认动画从水平向左/向右滑动更改为淡入/淡出动画。我是新作曲,我在互联网上没有找到任何有用的资源。如果有人知道这可以帮助我找到正确的解决方案。预先感谢。
val pagerState = rememberPagerState()
HorizontalPager(count = 3, state = pagerState
) { pagePosition ->
PagerScreen(onBoardingData = onBoardingDataList[pagePosition])
}
这里PagerScreen是每个屏幕的可组合函数。
使用推荐的
graphicsLayer
和 HorizontalPager
的解决方案:
val pagerState = rememberPagerState()
HorizontalPager(
state = pagerState,
modifier = Modifier.fillMaxWidth()
) { page ->
val isRtl =
LocalContext.current.resources.configuration.layoutDirection == LayoutDirection.RTL
Item(
// ...
modifier = Modifier.graphicsLayer {
val pageOffset =
((pagerState.currentPage - page) + pagerState.currentPageOffsetFraction)
alpha = lerp(
start = 0f,
stop = 1f,
fraction = 1f - pageOffset.absoluteValue.coerceIn(0f, 1f),
)
val fraction =
if (pagerState.currentPage != page) -pageOffset else 1f - pageOffset
translationX = lerp(
start = size.width,
stop = 0f,
fraction = if (isRtl) 2f - fraction else fraction,
)
}
)
}
我不确定使用
HorizontalPager
是否有更好的解决方案,所以我使用 swipeable
修饰符完成了这个解决方案。
@ExperimentalMaterialApi
@Composable
fun SwipeableSampleScreen5() {
val pages = listOf(
596 to Color(203, 41, 61),
801 to Color(107, 0, 141),
492 to Color(40, 38, 149),
718 to Color(56, 144, 244),
550 to Color(60, 149, 159)
)
val swipeableState = rememberSwipeableState(0)
// This Box is only to get the screen's width
BoxWithConstraints(Modifier.fillMaxWidth()) {
val widthPx = with(LocalDensity.current) {
maxWidth.toPx()
}
// Each anchor of the swipeable is the index * screen width
val anchors = remember(pages) {
List(pages.size) { index ->
-(index * widthPx) to index
}.toMap()
}
// This Box is capturing the swipe gesture
Box(
modifier = Modifier
.fillMaxSize()
.swipeable(
state = swipeableState,
anchors = anchors,
thresholds = { _, _ -> FractionalThreshold(0.5f) },
orientation = Orientation.Horizontal,
)
) {
// swipeableState provides the current index and the next index
val currentIndex = swipeableState.currentValue
val nextIndex = swipeableState.progress.to
// This Box is behind and will display the nextValue
Box(
Modifier
// graphicsLayer is applied to the content
.graphicsLayer {
alpha = 1f
},
) {
Box(
Modifier
.fillMaxSize()
.background(pages[nextIndex].second),
contentAlignment = Alignment.Center
) {
Text(
text = pages[nextIndex].first.toString(),
style = MaterialTheme.typography.h1.copy(color = Color.White),
)
}
}
// This Box is showing the current value which will change
// the alpha during the swiping
Box(
Modifier
.graphicsLayer {
alpha = 1f - swipeableState.progress.fraction
},
) {
Box(
Modifier
.fillMaxSize()
.background(pages[currentIndex].second),
contentAlignment = Alignment.Center
) {
Text(
text = pages[currentIndex].first.toString(),
style = MaterialTheme.typography.h1.copy(color = Color.White),
)
}
}
}
}
}
解决方案已评论,但为了更好地理解这篇文章对我帮助很大。
结果如下:
您可以在此处找到完整来源。