数组嵌套数组场景的懒加载实现

export  default class MyDataSource extends BasicDataSource { 
  private dataArray: TimeTable[] | Array<string> = [] 
 
  constructor(Datas: Array<TimeTable> | Array<string>) { 
    super() 
    this.dataArray = Datas 
  } 
 
  public totalCount(): number { 
    return this.dataArray.length; 
  } 
 
  public getData(index: number): TimeTable | string { 
    return this.dataArray[index]; 
  } 
 
  public addDataTimeTable(index: number, data: TimeTable): void { 
    this.dataArray.splice(index, 0, data); 
    this.notifyDataAdd(index); 
  } 
 
  public addDataString(index: number, data: string): void { 
    this.dataArray.splice(index, 0, data); 
    this.notifyDataAdd(index); 
  } 
 
  public pushDataTimeTable(data: TimeTable): void { 
    (this.dataArray as Array<TimeTable>).push(data); 
    this.notifyDataAdd(this.dataArray.length - 1); 
  } 
 
  public pushDataString(data: string): void { 
    (this.dataArray as Array<string>).push(data); 
    this.notifyDataAdd(this.dataArray.length - 1); 
  } 
}

@Component 
@Reusable 
export default struct TimeTableComponent{ 
  @State timeTable: TimeTable[]=[] 
  private data: MyDataSource = new MyDataSource(this.timeTable); 
  private hashMap: HashMap<string,MyDataSource> = new HashMap(); 
  
  build() { 
    Column(){ 
      List() { 
        LazyForEach(this.data, (item: TimeTable) => { 
          ListItemGroup({ header: itemHead(item.title), footer: itemFoot(item.projects.length) }) { 
            LazyForEach(this.hashMap.get(item.title), (project: string) => { 
              ListItem() { 
                Text(project) 
                  .width("100%") 
                  .height(100) 
                  .fontSize(20) 
                  .textAlign(TextAlign.Center) 
                  .backgroundColor(0xFFFFFF) 
              } 
            }, (item: string) => item) 
          } 
          .divider({ strokeWidth: 1, color: Color.Blue }) // 每行之间的分界线 
        }, (item: string) => item) 
      }.cachedCount(5) 
    } 
  } 
} 
  
@Builder 
function itemHead(text: string) { 
  Text(text) 
    .fontSize(20) 
    .backgroundColor(0x00BBCC) 
    .width("100%") 
    .padding(10) 
} 
  
@Builder 
function itemFoot(num: number) { 
  Text('共' + num + "节课") 
    .fontSize(16) 
    .backgroundColor(0xAABBDD) 
    .width("100%") 
    .padding(5) 
}