HarmonyOS WaterFlowDataSource数据不满屏的时候parallelGesture滑动没反应，满屏后可滑动？

Question

// 实现IDataSource接口的对象，用于瀑布流组件加载数据
export class WaterFlowDataSource implements IDataSource {
  private dataArray: number[] = []
  private listeners: DataChangeListener[] = []

  constructor(list: number[]) {
    this.dataArray = list
  }

  // 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.onDataAdd(index)
    })
  }

  // 通知控制器数据变化
  notifyDataChange(index: number): void {
    this.listeners.forEach(listener => {
      listener.onDataChange(index)
    })
  }

  // 通知控制器数据删除
  notifyDataDelete(index: number): void {
    this.listeners.forEach(listener => {
      listener.onDataDelete(index)
    })
  }

  // 通知控制器数据位置变化
  notifyDataMove(from: number, to: number): void {
    this.listeners.forEach(listener => {
      listener.onDataMove(from, to)
    })
  }

  //通知控制器数据批量修改
  notifyDatasetChange(operations: DataOperation[]): void {
    this.listeners.forEach(listener => {
      listener.onDatasetChange(operations);
    })
  }

  // 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
  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)
  }

  // 在指定索引位置删除一个元素
  public deleteItem(index: number): void {
    this.dataArray.splice(index, 1)
    this.notifyDataDelete(index)
  }

  // 重新加载数据
  public reload(): void {
    this.dataArray.splice(1, 1)
    this.dataArray.splice(3, 2)
    this.notifyDataReload()
  }
}

@Entry
@Component
struct PageWaterFlowList {
  @State minSize: number = 80
  @State maxSize: number = 180
  @State colors: number[] = [0xFFC0CB, 0xDA70D6, 0x6B8E23, 0x6A5ACD, 0x00FFFF, 0x00FF7F]
  dataSource: WaterFlowDataSource = new WaterFlowDataSource(new Array(4).fill(1))
  // dataSource: WaterFlowDataSource = new WaterFlowDataSource(new Array(30).fill(1))
  private itemWidthArray: number[] = []
  private itemHeightArray: number[] = []

  // 计算FlowItem宽/高
  getSize() {
    let ret = Math.floor(Math.random() * this.maxSize)
    return (ret > this.minSize ? ret : this.minSize)
  }

  // 设置FlowItem宽/高数组
  setItemSizeArray() {
    for (let i = 0; i < 20; i++) {
      this.itemWidthArray.push(this.getSize())
      this.itemHeightArray.push(this.getSize())
    }
  }

  aboutToAppear() {
    this.setItemSizeArray()
  }

  build() {
    Column() {
      Text('标题').height(40)
      Scroll() {
        Column() {
          Text('Text').height(200)
          WaterFlow() {
            LazyForEach(this.dataSource, (item: number, index: number) => {
              FlowItem() {
                Column() {
                  Text("N" + item).fontSize(12).height('16')
                  Image('res/waterFlowTest(' + item % 5 + ').jpg')
                }
              }
              .width('100%')
              .height(this.itemHeightArray[item % 100])
              .backgroundColor(this.colors[item % 5])
            }, (item: string, index: number) => item + index)
          }
          .columnsTemplate("1fr 1fr")
          .columnsGap(10)
          .rowsGap(5)
          .backgroundColor(0xFAEEE0)
          .width('100%')
          .height('100%')
          .nestedScroll({
            scrollForward: NestedScrollMode.PARENT_FIRST,
            scrollBackward: NestedScrollMode.SELF_FIRST,
          })
        }
        // 这个手势加上后  WaterFlow的PARENT_FIRST不生效
        .parallelGesture(
          PanGesture({ direction: PanDirection.Vertical })
            .onActionUpdate((event: GestureEvent) => {
              if (event) {
                console.error('onActionUpdate')
              }
            }),
          GestureMask.Normal
        )
      }
      .width('100%')
      .layoutWeight(1)
    }
    .width('100%')
    .height('100%')
  }
}

Answer 1

根据定位，目前组件层次：Scroll-Column-WaterFlow

0、同类手势基础规则：子组件优先响应手势，父子组件的手势是互斥关系，子组件响应了滑动手势，父组件就不会响应了

1、nestedScroll 这个是控制滚动类组件的嵌套，PARENT\_FIRST会让子组件WaterFlow的滑动手势冒泡到父组件

2、WaterFlo的父组件是Column，上面绑定了晃动手势PanGesture:Column就消费掉了滑动手势PanGesture,Scroll就响应不到滑动手势PanGesture

3、Column上滑动手势PanGesture的onActionUpdate只做了打印日志，没有具体行为，表现就是没有动作

.edgeEffect(EdgeEffect.None, {alwaysEnabled:true}) // 是否向父组件传递手势效果，true表示可以传