List使用问题有哪些？

@Entry  
@Component  
struct ListSnapPage {  
  private arr: number[] = []  
  private scrollerForList: Scroller = new Scroller()  
  
  aboutToAppear() {  
    for (let i = 0; i < 20; i++) {  
      this.arr.push(i)  
    }  
  }  
  
  build() {  
    Column() {  
      List({ space: 20, initialIndex: 0, scroller: this.scrollerForList }) {  
        ForEach(this.arr, (item: number) => {  
          ListItem() {  
            Text('' + item)  
              .width('100%').height(100).fontSize(16)  
              .textAlign(TextAlign.Center)  
          }  
          .borderRadius(10).backgroundColor(0xFFFFFF)  
          .width('100%')  
          .height('95%')  
        }, (item: number) => JSON.stringify(item))  
      }  
      .chainAnimation(true)  
      .edgeEffect(EdgeEffect.Spring)  
      .height('100%')  
      .width('100%')  
      .scrollSnapAlign(ScrollSnapAlign.CENTER)  
      .borderRadius(10)  
      .scrollBar(BarState.Off)  
      .backgroundColor(0xDCDCDC)  
    }  
    .width('100%')  
    .height('100%')  
    .backgroundColor(0xDCDCDC)  
  }  
}