鸿蒙开发-watch使用

import promptAction from '@ohos.promptAction'
@Entry
@Component
struct WatchCase {
  @State message: string = 'Hello World'
  @State
  @Watch('update')
  num: number = 0

  update() {
    promptAction.showToast({message: this.num.toString()})
  }
  build() {
    Row() {
      Column() {
        Text(this.num.toString()).fontSize(30)
        Divider().strokeWidth(6).color(Color.Red)
        ChildInfo({num: $num})
      }
      .width('100%')
    }
    .height('100%')
  }
}

@Component
struct ChildInfo {
  @Link
  num: number;
  build() {
    Text(this.num.toString()).fontSize(30)
      .onClick(() => {
        this.num++
      })
  }
}

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