更改默认滚动动画[关闭]

Question

我需要更改 Jetpack Compose for TV 的默认滚动动画。 对于我们的一些老客户来说，默认设置太快了。

这是如何实现的？

Answer 1

这是改变滚动动画的方法。

创建一个 BringIntoViewSpec 本地提供程序。

这是复制旧的 Pivot 行为的行为

fun PositionFocusedItemInLazyLayout(
parentFraction: Float = 0.3f,
childFraction: Float = 0f,
content: @Composable () -> Unit,) {
// This bring-into-view spec pivots around the center of the scrollable container
val bringIntoViewSpec = object : BringIntoViewSpec {

    private val cardAnimationSpec : AnimationSpec<Float> =  tween( durationMillis = 50, easing = FastOutLinearInEasing )

    override val scrollAnimationSpec: AnimationSpec<Float>
        get() = cardAnimationSpec

    override fun calculateScrollDistance(
        // Initial position of item requesting focus
        offset: Float,
        // Size of item requesting focus
        size: Float,
        // Size of the lazy container
        containerSize: Float
    ): Float {
        val childSmallerThanParent = size <= containerSize
        val initialTargetForLeadingEdge =
            parentFraction * containerSize - (childFraction * size)
        val spaceAvailableToShowItem = containerSize - initialTargetForLeadingEdge

        val targetForLeadingEdge =
            if (childSmallerThanParent && spaceAvailableToShowItem < size) {
                containerSize - size
            } else {
                initialTargetForLeadingEdge
            }

        return offset - targetForLeadingEdge
    }
}

// LocalBringIntoViewSpec will apply to all scrollable(s) in the hierarchy
CompositionLocalProvider(
    LocalBringIntoViewSpec provides bringIntoViewSpec,
    content = content,
)

}

重写scrollAnimationSpec Getter并提供您自己的，焦点系统使用它来设置滚动动画。

这可以通过放置在 LazyList/Row 上方来使用。

 PositionFocusedItemInLazyLayout(
        parentFraction = ParentRowFraction,
        childFraction = ChildRowFraction
    ) {

        LazyColumn(
            verticalArrangement = Arrangement.spacedBy(InternalPadding),
            horizontalAlignment = Alignment.CenterHorizontally,
            contentPadding = PaddingValues(top = VerticalPadding, bottom = VerticalPadding),
            state = columnState,
        ) { ....