HarmonyOS NEXT实战：父子组件间调用函数

@Entry
@Component
struct CallSubComponentMethodPage {
  private childController = new ChildController()
  private count: number = 0

  build() {
    Column({ space: 10 }) {
      Text('CallSubComponentMethod Page')
        .fontSize(20)
        .fontWeight(FontWeight.Bold)

      Button('CallSubComponentMethod').onClick(() => {
        this.count++
        this.childController.changeText(`this is text from parent, and count = ${this.count}`)
      })

      Child({ childController: this.childController })
    }
    .height('100%')
    .width('100%')
  }
}

//定义controller对象
class ChildController {
  changeText = (value: string) => {
  }
}

@Component
struct Child {
  @State private text: string = 'this is child text'
  childController: ChildController = new ChildController();

  aboutToAppear() {
    //给childController对应的方法赋值
    this.childController.changeText = this.changeText
  }

  //封装的能力
  private changeText = (value: string) => {
    this.text = value
  }

  build() {
    Column() {
      Text(this.text)
    }
    .backgroundColor('#EEEEEE')
    .width('90%')
    .height(100)
    .justifyContent(FlexAlign.Center)
  }
}

@Entry
@Component
struct CallParentComponentMethodPage {
  @State sonClickCount: number = 0

  build() {
    Column({ space: 10 }) {
      Text('CallParentComponentMethod Page')
        .fontSize(20)
        .fontWeight(FontWeight.Bold)
      Text(`sonClickCount = ${this.sonClickCount}`)

      Son({
        onSonClick: (count: number) => {
          this.sonClickCount = count
        }
      })
    }
    .height('100%')
    .width('100%')
  }
}

@Component
struct Son {
  private count: number = 0
  @Require onSonClick: (count: number) => void = (count: number) => {
  }

  build() {
    Column({ space: 10 }) {
      Text('Son Component')
      Button('Son Click').onClick(() => {
        this.count++
        this.onSonClick(this.count)
      })
    }
    .backgroundColor('#EEEEEE')
    .width('90%')
    .height(200)
    .padding(10)
  }
}