HarmonyOS 一个List，如何设置它最大高度比如300vp，然后可以比这个值小的情况下自适应包裹子布局？

Question

如题：HarmonyOS 一个List，如何设置它最大高度比如300vp，然后可以比这个值小的情况下自适应包裹子布局？

Answer 1

参考示例：

@Entry
@Component
struct ListExamplePage {
  private arr: number[] = [0, 1, 2, 3, 4, 5]

  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)
          }
        }, (item: string) => item)
      }
      .constraintSize({ maxHeight: 300 })
      .listDirection(Axis.Vertical) // 排列方向
      .scrollBar(BarState.Off)
      .friction(0.6)
      .divider({
        strokeWidth: 2,
        color: 0xFFFFFF,
        startMargin: 20,
        endMargin: 20
      }) // 每行之间的分界线
      .edgeEffect(EdgeEffect.Spring) // 边缘效果设置为Spring
      .onScrollIndex((firstIndex: number, lastIndex: number, centerIndex: number) => {
        console.info('first' + firstIndex)
        console.info('last' + lastIndex)
        console.info('center' + centerIndex)
      })
      .onScrollVisibleContentChange((start: VisibleListContentInfo, end: VisibleListContentInfo) => {
        console.log(' start index: ' + start.index +
          ' start item group area: ' + start.itemGroupArea +
          ' start index in group: ' + start.itemIndexInGroup)
        console.log(' end index: ' + end.index +
          ' end item group area: ' + end.itemGroupArea +
          ' end index in group: ' + end.itemIndexInGroup)
      })
      .onDidScroll((scrollOffset: number, scrollState: ScrollState) => {
        console.info(`onScroll scrollState = ScrollState` + scrollState + `, scrollOffset = ` + scrollOffset)
      })
      .width('90%')
    }
    .width('100%')
    .height('100%')
    .backgroundColor(0xDCDCDC)
    .padding({ top: 5 })
  }
}