HarmonyOS List某个item局部刷新？

Question

有List控件某个item局部刷新的文档或者demo么

Answer 1

参考简版demo：

@Observed
class Task {
  static id: number = 1
  name: string = `任务${Task.id++}`
  finished: boolean = false
}

class StatInfo {
  totalTask: number = 0
  finishTask: number = 0
}

@Styles
function card() {
  .width('95%')
  .padding(20)
  .backgroundColor(Color.White)
  .borderRadius(15)
  .shadow({ radius: 6, color: '#1F000000', offsetX: 2, offsetY: 4 })

}

@Extend(Text)
function finishTask() {
  .decoration({ type: TextDecorationType.LineThrough, color: '#B1B2B1' })
  .fontColor('#B1B2B1')

}


@Component
struct TaskStatistics {
  @Consume stat: StatInfo
  build() {
    Row() {
      Text('任务：')
        .fontSize(30)
        .fontWeight(FontWeight.Bold)

      Stack() {
        Progress({
          value: this.stat.finishTask,
          total: this.stat.totalTask,
          type: ProgressType.Ring
        })
          .width(100)
        Row() {
          Text(this.stat.finishTask.toString())
            .fontSize(24)
            .fontColor('#36D')
          Text(' / ' + this.stat.totalTask.toString())
            .fontSize(24)
        }
      }
    }
    .card()
    .margin({ top: 5, bottom: 10 })
    .justifyContent(FlexAlign.SpaceEvenly)

  }
}

@Component
struct TaskList {
  @Consume stat: StatInfo
  @State tasks: Task[] = []
  handleTaskChange: (res: string) => void = (res) => {
    console.log(res)
    this.stat.totalTask = this.tasks.length
    this.stat.finishTask = this.tasks.filter(item => item.finished).length
  }

  build() {
    Column() {
      Button('新增')
        .width(200)
        .margin({ bottom: 10 })
        .onClick(() => {
          this.tasks.push(new Task())
          this.handleTaskChange('2')
        })

      List({ space: 10 }) {
        ForEach(this.tasks, (task: Task, index) => {
          ListItem() {
            TaskListItem({ item: task, onTaskChange: this.handleTaskChange })
          }
          .swipeAction({ end: this.DeleteButton(index) })
        })
      }
    }
  }

  @Builder
  DeleteButton(index: number) {

    Button() {
      Image('')
        .backgroundColor(Color.Red)
        .width(20)
        .aspectRatio(1)
    }
    .width(40)
    .height(40)
    .type(ButtonType.Circle)
    .backgroundColor(Color.Red)
    .margin(5)
    .onClick(() => {
      this.tasks.splice(index,1)
      this.handleTaskChange('删除')
    })

  }
}


@Component
struct TaskListItem {
  @ObjectLink item: Task
  onTaskChange: (e: string) => void = () => {
  }

  build() {
    Row() {
      if (this.item.finished) {
        Text(this.item.name)
          .finishTask()
      } else {
        Text(this.item.name)
      }

      Checkbox()
        .shape(CheckBoxShape.ROUNDED_SQUARE)
        .select(this.item.finished)
        .onChange((val) => {
          this.item.finished = val
          this.onTaskChange(val? '选中':'未选中')
        })
    }
    .card()
    .justifyContent(FlexAlign.SpaceBetween)
  }
}

@Entry
@Component
struct TaskListPage {
  @Provide stat: StatInfo = new StatInfo()

  build() {

    Column({ space: 10 }) {
      Text('列表')
        .fontSize(20)
        .fontWeight(FontWeight.Bold)
        .width('100%')
        .height(56)
        .padding({left:20})

      TaskStatistics()

      TaskList()
    }
    .width('100%')
    .height('100%')
    .backgroundColor('#F1F2F3')
  }
}