HarmonyOS 内嵌在Tabs的组件不走onPageShow方法？

Question

如题：HarmonyOS 内嵌在Tabs的组件不走onPageShow方法？

Answer 1

Tabs组件切换不执行onPageShow生命周期，因为onPageShow是页面级的生命周期，tabs切换触发的是子组件组件级的生命周期aboutToAppear()，可以将showPage()放在该生命周期内调用，如果需要每一次切换都要执行TabContent中的showPage方法，这边推荐使用onTabBarClick(event: (index: number) =\> void)获取父组件当前点击的tabIndex，在父组件中通过@State定义一个currentTabIndex变量，在onTabBarClick回调中将index赋值给currentTabIndex，并将这个值传递给TabContent包裹的子组件。在子组件中通过@Props和@Watch来监听父组件传递值的不同，执行各个tabContent中的showPage方法。

demo参考：

// xxx.ets
import { FirstPage } from './FirstPage'

@Entry
@Component
struct TabsExample {
  @State fontColor: string = '#182431'
  @State selectedFontColor: string = '#007DFF'
  @State currentIndex: number = 0
  private controller: TabsController = new TabsController()
  @State mainPageState:boolean = false
  @Builder tabBuilder(index: number, name: string) {
    Column() {
      Text(name)
        .fontColor(this.currentIndex === index ? this.selectedFontColor : this.fontColor)
        .fontSize(16)
        .fontWeight(this.currentIndex === index ? 500 : 400)
        .lineHeight(22)
        .margin({ top: 17, bottom: 7 })
      Divider()
        .strokeWidth(2)
        .color('#007DFF')
        .opacity(this.currentIndex === index ? 1 : 0)
    }.width('100%')
  }

  build() {
    Column() {
      Tabs({ barPosition: BarPosition.Start, index: this.currentIndex, controller: this.controller }) {
        TabContent() {
          FirstPage({mainPageState:this.mainPageState}).width('100%').height('100%').backgroundColor('#00CB87')

        }.tabBar(this.tabBuilder(0, 'green'))

        TabContent() {
          Column().width('100%').height('100%').backgroundColor('#007DFF')
        }.tabBar(this.tabBuilder(1, 'blue'))

        TabContent() {
          Column().width('100%').height('100%').backgroundColor('#FFBF00')
        }.tabBar(this.tabBuilder(2, 'yellow'))

        TabContent() {
          Column().width('100%').height('100%').backgroundColor('#E67C92')
        }.tabBar(this.tabBuilder(3, 'pink'))
      }
      .vertical(false)
      .barMode(BarMode.Fixed)
      .barWidth(360)
      .barHeight(56)
      .animationDuration(400)
      .onChange((index: number) => {
        this.currentIndex = index
      })
      .width('100%')
      .height('100%')
      .margin({ top: 52 })
      .backgroundColor('#F1F3F5')
    }.width('100%')
  }

  onPageShow(): void {
    console.log('index--- onPageShow')
    this.mainPageState = true
  }
  onPageHide(): void {
    console.log('index--- onPageHide')
    this.mainPageState = false
  }
}

import { router } from '@kit.ArkUI';
import { FaultLogger } from '@kit.PerformanceAnalysisKit';

@Entry
@Component
export struct FirstPage {
  @State message: string = 'Hello World';
  @Link @Watch('mainIsShow') mainPageState:boolean
  build() {
    Row() {
      Column() {
        Text(this.message)
          .fontSize(50)
          .fontWeight(FontWeight.Bold).onClick(()=>{
          router.pushUrl({
            url:'pages/DetailPage',

          })

        })
      }
      .width('100%')
    }
    .height('100%')
  }
  mainIsShow(){
    console.log('mainIsShow--',this.mainPageState)
  }
  aboutToAppear(): void {
    console.log('firstPAGE--- aboutToAppear')
  }

  onPageShow(): void {
    console.log('firstPAGE--- onPageShow')
  }
  onPageHide(): void {
    console.log('firstPAGE--- onPageHide')
  }
  aboutToRecycle(): void {
    console.log('firstPAGE--- aboutToRecycle')
  }

}

import { Notification } from '@kit.NotificationKit';

@Entry
@Component
struct DetailPage {
  @State message: string = '详情';

  build() {
    Row() {
      Column() {
        Text(this.message)
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
      }
      .width('100%')
    }
    .height('100%')
  }
  onPageShow(): void {
  }
  onPageHide(): void {

    console.log('firstPAGE--- onPageHide')
  }
  onBackPress(): boolean | void {
    console.log('firstPAGE--- onBackPress')
  }
}