HarmonyOS 页面反向传值怎么传？

Question

如题：HarmonyOS 页面反向传值怎么传？

Answer 1

问题场景

从A页面跳转到B页面，当从B页面返回时，想给A页面传递参数，如何传递

新建三个页面分别是Index2、APage、BPage，实现了A传给B，B传给A，互传的功能。代码如下：

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

@Entry
@Component
struct APage {
  @State message: string = '我是A';
  fromPage : Record<string,string> = router.getParams() as Record<string,string>
  @StorageLink('flag') flag : string = ''
  build() {
    Row() {
      Column() {
        Text(this.message)
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
        Text("跳转到B")
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .onClick(()=>{
            if (this.fromPage==null) {
              router.pushUrl({
                url:"pages/BPage",
                params:{data:"BPage"}
              })
            } else{
              if (this.fromPage!=null) {
                console.log("我在A页面,存入了" + this.fromPage['data'].toString())
                AppStorage.set('flag', this.fromPage['data'].toString())
                console.log("我在A页面,输出flag：" + this.flag)
              }
              router.pushUrl({
                url:"pages/BPage",
                params:{data:"BPage"}
              })
            }
          })
        Text("跳转到Index2")
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .onClick(()=>{
            router.pushUrl({
              url:"pages/Index2"
            })
          })
      }
      .width('100%')
    }
    .height('100%')
  }
}


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

@Entry
@Component
struct BPage {
  @State message: string = '我是B';
  @StorageLink('flag') flag : string = ''
  fromPage : Record<string,string> = router.getParams() as Record<string,string>
  build() {
    Row() {
      Column() {
        Text(this.message)
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
        Text("跳转到A")
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .onClick(()=>{
            if (this.fromPage!=null) {
              console.log("我在B页面,存入了"+this.fromPage['data'].toString())
              AppStorage.set('flag',this.fromPage['data'].toString())
              console.log("我在B页面,输出flag："+this.flag)
            }
            router.pushUrl({
              url:"pages/APage",
              params:{data:"APage"}
            })
          })
        Text("跳转到Index2")
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .onClick(()=>{
            router.pushUrl({
              url:"pages/Index2"
            })
          })
      }
      .width('100%')
    }
    .height('100%')
  }
}

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

@Entry
@Component
struct Index2 {
  @State message: string = '当前页面';

  @StorageLink('flag') @Watch('onChange') flag : string = ''

  onChange(){
    console.log(this.flag)
  }
  build() {
    Row() {
      Column() {
        Text(this.message)
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .onClick(()=>{
            if (this.flag=='') {
              console.log('flag初始化失败')
            } else {
              router.pushUrl({
                url:"pages/"+this.flag
              })
            }
          })
      }
      .width('100%')
    }
    .height('100%')
  }
}