介紹

本篇主要介紹如何在HarmonyOS中，在頁面跳轉之間如何傳值

HarmonyOS 的頁面指的是帶有@Entry裝飾器的文件，其不能獨自存在，必須依賴UIAbility這樣的組件容器

如下是官方關于State模型開發模式下的應用包結構示意圖，Page就是帶有@Entry裝飾器的文件

0000000000011111111.20231123162458.56374277887047155204379708661912.png

那么在頁面跳轉時，在代碼層面最長路徑其實是有兩步 1，打開UIAbility 2. 打開Page

整體交互效果

傳值理論

基于LocalStorage
基于EventHub
基于router

準備

搜狗高速瀏覽器截圖20240326151547.png

我們熟讀玩文檔后，開始創建一個Demo工程，選擇Stage模型

代碼實踐

1.定制主入口頁面

功能

頁面曝光停留時長計算
增加進入二級頁面入口

import systemDateTime from '@ohos.systemDateTime'
import router from '@ohos.router'

@Entry
@Component
struct Index {
  @State message: string = '頁面跳轉'

  private showDuration: number = 0

  onPageShow() {

    this.showDuration = 0
    systemDateTime.getCurrentTime(false, (error, data) = > {
      if(!error){
        this.showDuration = data
      }
    })

  }

  build() {
    Row() {
      Column() {
        Text(this.message)
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .onClick(()= >{
            systemDateTime.getCurrentTime(false, (error, data) = > {
              router.pushUrl({ url: 'pages/OpenPage', params: {
                "from": "pages/Home.ets",
                "data": {
                  "duration":(data - this.showDuration)
                }
              } })
                .then(() = > {
                  console.info('Succeeded in jumping to the second page.')
                }).catch((error) = > {
                console.log(error)
              })
            })
          })
      }
      .width('100%')
    }
    .height('100%')
  }

}

2.添加二級頁面

注意

OpenPage.ets需要在main_pages.json中的注冊

{
  "src": [
    "pages/Index" //主入口頁面
    ,"pages/OpenPage" //二級頁面
    ,"pages/Test" //三級頁面
    ,"pages/LocalStorageAbilityPage" //三級頁面
  ]
}

功能

展示主入口頁面停留時間
添加通過UIAbility方式打開頁面的入口
添加通過router.pushUrl方式打開頁面的入口

/**
 * 路由 3.1/4.0 文檔
 * https://developer.harmonyos.com/cn/docs/documentation/doc-references-V3/js-apis-router-0000001478061893-V3#ZH-CN_TOPIC_0000001523808578__routerpushurl9
 *
 */
import router from '@ohos.router';
import common from '@ohos.app.ability.common';


@Entry
@Component
struct OpenPageIndex{
  @State extParams: string = ''
  private expParamsO: Object
  private context = getContext(this) as common.UIAbilityContext;

  aboutToAppear(){
    this.expParamsO = router.getParams();
    this.extParams = JSON.stringify(this.expParamsO, null, 't');
  }

  build(){
    Column(){

      List(){
            ListItemGroup() {
              ListItem() {
                Text(this.extParams)
                  .width('96%')
                  .fontSize(18)
                  .fontColor(Color.Green)
                  .backgroundColor(Color.White)
              }.width('100%')
              .align(Alignment.Start)
              .backgroundColor(0xFFFFFF)
              .borderRadius('16vp')
              .padding('12vp')

            }.divider({
              strokeWidth: 1,
              startMargin: 0,
              endMargin: 0,
              color: '#ffe5e5e5'
            })

        ListItemGroup() {

          ListItem() {
            Text('啟動UIAbility頁面')
              .width('96%')
              .fontSize(18)
              .fontColor(Color.Black)
              .backgroundColor(Color.White)
          }.width('100%')
          .height(50)
          .align(Alignment.Start)
          .backgroundColor(0xFFFFFF)
          .padding({ left: 10 })
          .onClick(() = > {
            this.startAbilityTest('LocalStorageAbility')
          })

          ListItem() {
            Text('啟動@Entry頁面')
              .width('96%')
              .fontSize(18)
              .fontColor(Color.Black)
              .backgroundColor(Color.White)
          }.width('100%')
          .height(50)
          .align(Alignment.Start)
          .backgroundColor(0xFFFFFF)
          .padding({ left: 10 })
          .onClick(() = > {
            router.pushUrl({ url: 'pages/Test', params: {
              "from": "pages/OpenPage.ets"
            } })
              .then(() = > {
                console.info('Succeeded in jumping to the second page.')
              }).catch((error) = > {
              console.log(error)
            })
          })

        }.divider({
          strokeWidth: 1,
          startMargin: 0,
          endMargin: 0,
          color: '#ffe5e5e5'
        })

      }.width('100%').height('90%')
      .divider({
        strokeWidth: px2vp(20),
        startMargin: 0,
        endMargin: 0,
        color: '#ffe5e5e5'
      })

    }.width('100%').height('100%')
    .padding({ top: px2vp(111) , left: '12vp', right: '12vp'})
    .backgroundColor('#ffe5e5e5')
  }

  async startAbilityTest(name: string) {
    try {
      let want = {
        deviceId: '', // deviceId為空表示本設備
        bundleName: 'com.harvey.testharmony',
        abilityName: name,
        parameters:{
            from: 'OpenPage.ets',
            data: {
              hello: 'word',
              who: 'please'
            }
        }
      };
      let context = getContext(this) as common.UIAbilityContext;
      await context.startAbility(want);
      console.info(`explicit start ability succeed`);
    } catch (error) {
      console.info(`explicit start ability failed with ${error.code}`);
    }

  }

}

3. 添加三級頁面

注意

先要添加注冊一個新的容器，這里命名為：LocalStorageAbility.ets 容器需要在module.json5中聲明

{
    "name": "LocalStorageAbility",
    "srcEntry": "./ets/entryability/LocalStorageAbility.ets",
    "description": "$string:EntryAbility_desc",
    "icon": "$media:icon",
    "label": "$string:EntryAbility_label",
    "startWindowIcon": "$media:icon",
    "startWindowBackground": "$color:start_window_background"
  }

import window from '@ohos.window';
import UIAbility from '@ohos.app.ability.UIAbility';


let para:Record< string,string > = { 'PropA': JSON.stringify({ 'from': 'LocalStorageAbility'}) };
let localStorage: LocalStorage = new LocalStorage(para);

export default class LocalStorageAbility extends UIAbility {

  storage: LocalStorage = localStorage

  onCreate(want, launchParam) {

  }

  onWindowStageCreate(windowStage: window.WindowStage) {
    super.onWindowStageCreate(windowStage)

    windowStage.loadContent('pages/LocalStorageAbilityPage', this.storage, (err, data) = > {
      if (err.code) {
               return;
      }

      setTimeout(()= >{
        let eventhub = this.context.eventHub;
        console.log(para['PropA'])
        eventhub.emit('parameters', para['PropA']);
      }, 0)

    });
  }

}

Test.ets和LocalStorageAbilityPage.ets需要在main_pages.json中的注冊

{
  "src": [
    "pages/Index" //主入口頁面
    ,"pages/OpenPage" //二級頁面
    ,"pages/Test" //三級頁面
    ,"pages/LocalStorageAbilityPage" //三級頁面
  ]
}

功能

展示基于LocalStorage，EventHub，router 三種傳值方式的數據
LocalStorageAbilityPage.ets 文件

展示LocalStorage，EventHub方式的數據

import router from '@ohos.router';
import common from '@ohos.app.ability.common';

// 通過GetShared接口獲取stage共享的LocalStorage實例
let storage = LocalStorage.GetShared()

@Entry(storage)
@Component
struct LocalStorageAbilityPageIndex {
  @State message: string = ''
  // can access LocalStorage instance using
  // @LocalStorageLink/Prop decorated variables
  @LocalStorageLink('PropA') extLocalStorageParms: string = '';

  context = getContext(this) as common.UIAbilityContext;

  aboutToAppear(){
    this.eventHubFunc()
  }

  build() {
    Row() {
      Column({space: 50}) {

        Column({space: 10}){
          Text('LocalStorage傳值內容')
          Text(JSON.stringify(JSON.parse(this.extLocalStorageParms), null, 't'))
            .fontSize(18)
            .fontColor(Color.Green)
            .backgroundColor(Color.White)
            .width('100%')
            .padding('12vp')
            .borderRadius('16vp')
        }

        Column({space: 10}){
          Text('eventHub傳值內容')
          Text(this.message)
            .fontSize(18)
            .fontColor(Color.Green)
            .backgroundColor(Color.White)
            .width('100%')
            .padding('12vp')
            .borderRadius('16vp')
        }

      }.width('100%').height('100%')
      .padding({ top: px2vp(111) , left: '12vp', right: '12vp'})
      .backgroundColor('#ffe5e5e5')
    }
    .height('100%')

  }

  eventHubFunc() {
    this.context.eventHub.on('parameters', (...data) = > {
        this.message = JSON.stringify(JSON.parse(data[0]), null, 't')
    });
  }

}