HarmonyOS 如何给垂直滚动的List组件顶部添加渐隐效果？

Question

如何给垂直滚动的List组件顶部添加渐隐效果

Answer 1

可以参考如下demo:

@Entry
@Component
struct page240527110725022 {
  private arr: number[] = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

  @Builder
  overlayBuilder() {
    Stack()
      .height("100%")
      .width("100%")
      .linearGradient({
        direction: GradientDirection.Bottom, // 渐变方向
        colors: [["#00FFFFFF", 0.0], ["#FFFFFFFF", 0.2]] // 数组末尾元素占比小于1时满足重复着色效果
      })
      .blendMode(BlendMode.DST_IN, BlendApplyType.OFFSCREEN)
      .hitTestBehavior(HitTestMode.None)
  }

  build() {
    Column() {
      List({ space: 20, initialIndex: 0 }) {
        ForEach(this.arr, (item: number) => {
          ListItem() {
            Text('' + item)
              .width('100%')
              .height(100)
              .fontSize(16)
              .textAlign(TextAlign.Center)
              .borderRadius(10)
              .backgroundColor(0xFFFFFF)
          }
          .onClick(() => {
            console.log('is click')
          })
        }, (item: string) => item)
      }.width('90%')
      .scrollBar(BarState.Off)
      .overlay(this.overlayBuilder())
      .blendMode(BlendMode.SRC_OVER, BlendApplyType.OFFSCREEN)
    }.width('100%').height('100%').backgroundColor(0xDCDCDC).padding({ top: 5 })
  }
}