AlphabetIndexer组件没有暴露方法跳转到指定index

class CarTable {  
  title: string = ''  
  projects: string[] = []  
}  
  
@Entry  
@Component  
struct AlphabetIndexPage {  
  private value: string[] = ['选', 'A', 'B', 'C', 'D', 'E', 'F', 'G',  
    'H', 'I', 'J', 'K', 'L', 'M', 'N',  
    'O', 'P', 'Q', 'R', 'S', 'T', 'U',  
    'V', 'W', 'X', 'Y', 'Z']  
  @State selectedIndex: number = 0  
  listScroller: ListScroller = new ListScroller()  
  
  private carList: CarTable[] = [  
    {  
      title: 'A',  
      projects: ['xx', 'xx', 'xx', 'xx', 'xx', 'xx', 'xx', 'xxx', 'xxx', 'xxxx', 'xxx', 'xxx']  
    },  
    {  
      title: 'B',  
      projects: ['xx', 'xx', 'xx', 'xx', 'xx', 'xxx', 'xx', 'xxx', 'xxx', 'xx', 'xxx', 'xxx', 'xxxx']  
    },  
    {  
      title: 'C',  
      projects: ['xx', 'xx', 'xx', 'xx', 'xx', 'xx', 'xx', 'xx', 'xx', 'xx', 'xx', 'xxx']  
    },  
    {  
      title: 'D',  
      projects: ['xxx', 'xxx', 'xxx', 'xxx', 'xxx', 'xxx', 'xxx', 'xxx', 'xx', 'xx', 'xx']  
    },  
    {  
      title: 'E',  
      projects: ['xxx', 'xxx', 'xx', 'xxx']  
    },  
    {  
      title: 'F',  
      projects: ['xxx', 'xx', 'xxx', 'xxx', 'xx', 'xx', 'xxx', 'xxx']  
    }  
  ]  
  
  @Builder  
  itemHead(text: string) {  
    Text(text)  
      .fontSize(20)  
      .backgroundColor(0xAABBCC)  
      .width("100%")  
      .padding(10)  
  }  
  
  build() {  
    Stack({ alignContent: Alignment.Start }) {  
      Row() {  
        List({ space: 0, initialIndex: 0, scroller: this.listScroller }) {  
          ForEach(this.carList, (item: CarTable) => {  
            ListItemGroup({ header: this.itemHead(item.title) }) {  
              ForEach(item.projects, (project: string) => {  
                ListItem() {  
                  Text(project)  
                    .width("100%")  
                    .height(60)  
                }  
              }, (item: string) => item)  
            }  
          })  
        }  
        .width('70%')  
        .height('100%')  
        .sticky(StickyStyle.Header)  
        .scrollBar(BarState.Off)  
        .edgeEffect(EdgeEffect.None)  
        .onScrollIndex((start: number, end: number) => {  
          this.selectedIndex = end  
        })  
  
        AlphabetIndexer({ arrayValue: this.value, selected: 0 })  
          .selected(this.selectedIndex)  
          .selectedColor(0xFFFFFF)// 选中项文本颜色  
          .selectedBackgroundColor(0xCCCCCC)// 选中项背景颜色  
          .selectedFont({ size: 16, weight: FontWeight.Bolder })// 选中项字体样式  
          .itemSize(28)// 每一项的尺寸大小  
          .onSelect((index: number) => {  
            this.listScroller.scrollToItemInGroup(index - 1, 0, true)  
          })  
      }  
      .width('100%')  
      .height('100%')  
    }  
  }  
}