HarmonyOS List组件和WaterFlow组件增强

//index.ets 
import { WaterFlowDataSource } from './WaterFlowDataSource' 
@Entry 
@Component 
struct Index { 
  @State Number: String[] = ['0', '1', '2', '3', '4'] 
  @State minSize: number = 80 
  @State maxSize: number = 180 
  @State fontSize: number = 24 
  @State colors: number[] = [0xFFC0CB, 0xDA70D6, 0x6B8E23, 0x6A5ACD, 0x00FFFF, 0x00FF7F] 
  scroller: Scroller = new Scroller() 
  dataSource: WaterFlowDataSource = new WaterFlowDataSource() 
  private itemWidthArray: number[] = [] 
  private itemHeightArray: number[] = [] 
  // 计算flow item宽/高 
  getSize() { 
    let ret = Math.floor(Math.random() * this.maxSize) 
    return (ret > this.minSize ? ret : this.minSize) 
  } 
  // 保存flow item宽/高 
  getItemSizeArray() { 
    for (let i = 0; i < 100; i++) { 
      this.itemWidthArray.push(this.getSize()) 
      this.itemHeightArray.push(this.getSize()) 
    } 
  } 
  aboutToAppear() { 
    this.getItemSizeArray() 
  } 
  @Builder 
  itemFoot() { 
    Column() { 
      Text(`Footer`) 
        .fontSize(10) 
        .backgroundColor(Color.Red) 
        .width(50) 
        .height(50) 
        .align(Alignment.Center) 
        .margin({ top: 2 }) 
    } 
  } 
  build() { 
    Column() { 
      Scroll(this.scroller) { 
        Column({space:10}) { 
          Grid() { 
            ForEach(this.Number, (day: string) => { 
              ForEach(this.Number, (day: string) => { 
                GridItem() { 
                  Text(day) 
                    .fontSize(16) 
                    .backgroundColor(0xF9CF93) 
                    .width('100%') 
                    .height('100%') 
                    .textAlign(TextAlign.Center) 
                } 
              }) 
            }) 
          } 
          .columnsTemplate('1fr 1fr 1fr 1fr') 
          .rowsTemplate('1fr 1fr') 
          .columnsGap(10) 
          .rowsGap(10) 
          .width('90%') 
          .backgroundColor(0xFAEEE0) 
          .height(140) 
 
          Swiper(new SwiperController()) { 
            ForEach(["测试1", "测试2", "测试3", "测试4", "测试5", "测试6"], (item: string) => { 
              Text(item).fontSize(20) 
            }) 
          }.autoPlay(true) 
          .vertical(false) 
          .indicator(false) 
          .loop(true) 
          .width('90%') 
          .backgroundColor(Color.Pink) 
          .height(100) 
 
          WaterFlow({scroller:this.scroller}) { 
            LazyForEach(this.dataSource, (item: number) => { 
              FlowItem() { 
                Column() { 
                  Text("N" + item).fontSize(12).height('16') 
                  Image('res/waterFlowTest(' + item % 5 + ').jpg') 
                    .objectFit(ImageFit.Fill) 
                    .width('100%') 
                    .layoutWeight(1) 
                } 
              } 
              .onAppear(() => { 
                // 即将触底时提前增加数据 
                if (item + 20 == this.dataSource.totalCount()) { 
                  for (let i = 0; i < 100; i++) { 
                    this.dataSource.addLastItem() 
                  } 
                } 
              }) 
              .width('100%') 
              .height(this.itemHeightArray[item % 100]) 
              .backgroundColor(this.colors[item % 5]) 
            }, (item: string) => item) 
          } 
          .columnsTemplate("1fr 1fr") 
          .columnsGap(10) 
          .rowsGap(5) 
          .backgroundColor(0xFAEEE0) 
          .width('90%') 
          .height('100%') 
          .nestedScroll({ 
            scrollForward: NestedScrollMode.PARENT_FIRST, 
            scrollBackward: NestedScrollMode.SELF_FIRST 
          }) 
 
        }.width('100%').backgroundColor(0xDCDCDC) 
      } 
      .backgroundColor(Color.Yellow) 
      .height('100%') 
      .edgeEffect(EdgeEffect.Spring) 
 
    } 
  } 
} 
 
//WaterFlowDataSource.ets 
export class WaterFlowDataSource implements IDataSource { 
  private dataArray: number[] = [] 
  private listeners: DataChangeListener[] = [] 
  constructor() { 
    for (let i = 0; i < 100; i++) { 
      this.dataArray.push(i) 
    } 
  } 
  // 获取索引对应的数据 
  public getData(index: number): number { 
    return this.dataArray[index] 
  } 
  // 通知控制器数据重新加载 
  notifyDataReload(): void { 
    this.listeners.forEach(listener => { 
      listener.onDataReloaded() 
    }) 
  } 
  // 通知控制器数据增加 
  notifyDataAdd(index: number): void { 
    this.listeners.forEach(listener => { 
      listener.onDataAdded(index) 
    }) 
  } 
  // 通知控制器数据变化 
  notifyDataChange(index: number): void { 
    this.listeners.forEach(listener => { 
      listener.onDataChanged(index) 
    }) 
  } 
  // 通知控制器数据删除 
  notifyDataDelete(index: number): void { 
    this.listeners.forEach(listener => { 
      listener.onDataDeleted(index) 
    }) 
  } 
  // 通知控制器数据位置变化 
  notifyDataMove(from: number, to: number): void { 
    this.listeners.forEach(listener => { 
      listener.onDataMoved(from, to) 
    }) 
  } 
  // 获取数据总数 
  public totalCount(): number { 
    return this.dataArray.length 
  } 
  // 注册改变数据的控制器 
  registerDataChangeListener(listener: DataChangeListener): void { 
    if (this.listeners.indexOf(listener) < 0) { 
      this.listeners.push(listener) 
    } 
  } 
  // 注销改变数据的控制器 
  unregisterDataChangeListener(listener: DataChangeListener): void { 
    const pos = this.listeners.indexOf(listener) 
    if (pos >= 0) { 
      this.listeners.splice(pos, 1) 
    } 
  } 
  // 增加数据 
  public add1stItem(): void { 
    this.dataArray.splice(0, 0, this.dataArray.length) 
    this.notifyDataAdd(0) 
  } 
  // 在数据尾部增加一个元素 
  public addLastItem(): void { 
    this.dataArray.splice(this.dataArray.length, 0, this.dataArray.length) 
    this.notifyDataAdd(this.dataArray.length - 1) 
  } 
  // 在指定索引位置增加一个元素 
  public addItem(index: number): void { 
    this.dataArray.splice(index, 0, this.dataArray.length) 
    this.notifyDataAdd(index) 
  } 
  // 删除第一个元素 
  // 删除第一个元素 
  public delete1stItem(): void { 
    this.dataArray.splice(0, 1) 
    this.notifyDataDelete(0) 
  } 
  // 删除第二个元素 
  public delete2ndItem(): void { 
    this.dataArray.splice(1, 1) 
    this.notifyDataDelete(1) 
  } 
  // 删除最后一个元素 
  public deleteLastItem(): void { 
    this.dataArray.splice(-1, 1) 
    this.notifyDataDelete(this.dataArray.length) 
  } 
  // 重新加载数据 
  public reload(): void { 
    this.dataArray.splice(1, 1) 
    this.dataArray.splice(3, 2) 
    this.notifyDataReload() 
  } 
}