HarmonyOS 获取List中当前屏幕可见的ListItem

@Entry 
@Component 
struct ListExample { 
  private arr: (number | string)[] = [0, '概览', '周边', 3, 4, '房源', 6, 7, '小区', 9, 10, 11, 12, 13, 14, 15] 
  private tabArr: string[] = ['概览', '周边', '房源', '小区'] 
  @State currentIndex: number = 0 
 
  build() { 
    Column() { 
      Row() { 
        ForEach(this.tabArr, (item: string, index: number) => { 
          Text(item) 
            .fontColor(this.currentIndex === index ? Color.Blue : '') 
        }) 
      } 
      .width('100%') 
      .padding({ left: 20 }) 
      .alignItems(VerticalAlign.Top) 
 
      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) 
      } 
      .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) 
        if (firstIndex == 1) { 
          this.currentIndex = 0 
        } else if (firstIndex == 2) { 
          this.currentIndex = 1 
        } else if (firstIndex == 5) { 
          this.currentIndex = 2 
        } else if (firstIndex == 8) { 
          this.currentIndex = 3 
        } 
      }) 
      .width('90%') 
    } 
    .width('100%') 
    .height('100%') 
    .backgroundColor(0xDCDCDC) 
    .padding({ top: 5 }) 
  } 
}