ets/pages/Index.ets

import router from '@ohos.router';

@Entry
@Component
struct Index {
  @State title: string = 'Index Page';
  @State message: string = ''

  onPageShow(): void { // 页面每次显示时触发。使用aboutToAppear页面没反应。
    let record = router.getParams() as Record<string, string>
    if (record) {
      this.message = record['backMsg']
    }
  }

  build() {
    Row() {
      Column() {
        Text(this.title)
          .id('IndexPage')
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
        // .alignRules({
        //   center: { anchor: '__container__', align: VerticalAlign.Center },
        //   middle: { anchor: '__container__', align: HorizontalAlign.Center }
        // })
        Text(this.message).fontSize(20).opacity(.6)
        Blank()
        Button('Next').width(260).height(45).fontSize(20).onClick(() => {
          router.pushUrl({ url: 'pages/SecondPage', params: { sendMsg: 'Index页面传来的数据' } })
        })
      }
      .width('100%')
      .height(160)
    }
    .height('100%')
    .width('100%')
  }
}

ets/pages/SecondPage

import router from '@ohos.router';

@Entry
@Component
struct SecondPage {
  @State title: string = 'Second Page';
  @State message: string = (router.getParams() as Record<string, string>)['sendMsg']

  build() {
    Row() {
      Column() {
        Text(this.title)
          .id('SecondPage')
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
        // .alignRules({
        //   center: { anchor: '__container__', align: VerticalAlign.Center },
        //   middle: { anchor: '__container__', align: HorizontalAlign.Center }
        // })
        Text(this.message).fontSize(20).opacity(.6)
        Blank()
        Button('Back').width(260).height(45).fontSize(20).onClick(() => {
          router.showAlertBeforeBackPage({ message: '确定要返回界面吗？' })
          router.back({
            url: 'pages/Index',
            params: {
              backMsg: 'Second页面传来的数据'
            }
          })
        })
      }
      .width('100%')
      .height(160)
    }
    .height('100%')
    .width('100%')
  }
}