HarmonyOS 鸿蒙Next：Tabs+TabContent切换页面时可通过onVisibleAreaChange感知显示与隐藏

HarmonyOS 鸿蒙Next：Tabs+TabContent切换页面时可通过onVisibleAreaChange感知显示与隐藏

@Entry
@Component
struct Page32 {
  @State fontColor: string = '#182431'
  @State selectedFontColor: string = '#007DFF'
  @State currentIndex: number = 0
  private controller: TabsController = new TabsController()

  @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() {
          Column().width('100%').height('100%').backgroundColor('#00CB87')
          .onVisibleAreaChange([0.0, 1.0], (isVisible: boolean, currentRatio: number) => {
              console.info('Test Text isVisible: ' + isVisible + ', currentRatio:' + currentRatio)
              if (isVisible && currentRatio >= 1.0) {
                console.info('首页显示了')
              }

              if (!isVisible && currentRatio <= 0.0) {
                console.info('首页隐藏了')
              }
            })
        }.tabBar(this.tabBuilder(0, '首页'))


        TabContent() {
          Column().width('100%').height('100%').backgroundColor('#007DFF')
            .onVisibleAreaChange([0.0, 1.0], (isVisible: boolean, currentRatio: number) => {
              console.info('Test Text isVisible: ' + isVisible + ', currentRatio:' + currentRatio)
              if (isVisible && currentRatio >= 1.0) {
                console.info('新闻页显示了')
              }

              if (!isVisible && currentRatio <= 0.0) {
                console.info('新闻页隐藏了')
              }
            })
        }.tabBar(this.tabBuilder(1, '新闻'))

        TabContent() {
          Column().width('100%').height('100%').backgroundColor('#FFBF00')
            .onVisibleAreaChange([0.0, 1.0], (isVisible: boolean, currentRatio: number) => {
              console.info('Test Text isVisible: ' + isVisible + ', currentRatio:' + currentRatio)
              if (isVisible && currentRatio >= 1.0) {
                console.info('我的页显示了')
              }

              if (!isVisible && currentRatio <= 0.0) {
                console.info('我的页隐藏了')
              }
            })
        }.tabBar(this.tabBuilder(2, '我的'))

      }
      .vertical(false)
      .barMode(BarMode.Fixed)
      .barWidth(360)
      .barHeight(56)
      .animationDuration(400)
      .onChange((index: number) => {
        this.currentIndex = index
      })
      .width(360)
      .height(296)
      .margin({ top: 52 })
      .backgroundColor('#F1F3F5')
    }.width('100%')
  }
}