HarmonyOS 鸿蒙Next 侧滑系统返回监听

通常返回监听方案，在各NavDestination中监听：
https://developer.huawei.com/consumer/cn/doc/harmonyos-faqs-V5/faqs-arkui-273-V5

希望在navigation上监听

1. 可以传递方法到子页面中，每个NavDestination的onBackPressed里调用
2. 监听路由信息，自己根据路由变化做判断，参考

@Watch('backPressChild') 
@Provide('pageInfos') 
pageInfos: NavPathStack = new NavPathStack()

1. 使用customNavContentTransition监听返回
   参考：
   https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/ts-basic-components-navigation-V5#customnavcontenttransition11

// Index.ets
import { SegmentButton } from '@kit.ArkUI'
import { ItemRestriction, SegmentButtonOptions, SegmentButtonTextItem } from '@ohos.arkui.advanced.SegmentButton'
import { PageOneTmp } from './navigationOne'
import { pageTwoTmp } from './navigationTwo'
import { Pages } from './navigationTwo'

@Entry
@Component
struct NavigationExample {
  @Watch('backPressChildWatch') @Provide('pageInfos') pageInfos: NavPathStack = new NavPathStack()

  @State tabSelectedIndexes: number[] = [1]

  backPressChildWatch(){
    console.info("监听到路由变化:",JSON.stringify(this.pageInfos))
  }

  backPressChild(){
    console.info("传入子页面返回回调:",JSON.stringify(this.pageInfos))
  }

  @State tabOptions: SegmentButtonOptions = SegmentButtonOptions.tab({
    buttons: [{ text: '最热' }, { text: '最新' }] as ItemRestriction<SegmentButtonTextItem>,
    backgroundColor: '#f8f6f6',
    selectedBackgroundColor: '#f8f6f6',
    backgroundBlurStyle: BlurStyle.NONE
  })

  @Builder
  PageMap(name: string,params:string) {
    if (name === 'web') {
      PageOneTmp({backF:this.backPressChild})
    } else if (name === 'pageTwo') {
      pageTwoTmp({ names: name, values: this.pageInfos } as Pages)
    }
  }

  build() {
    Navigation(this.pageInfos) {
      Column () {
        SegmentButton({
          options: this.tabOptions,
          selectedIndexes: $tabSelectedIndexes
        }).width(80).height(25)
        Button('pushPath', { stateEffect: true, type: ButtonType.Capsule })
          .width('80%')
          .height(40)
          .margin(20)
          .onClick(() => {
            this.pageInfos.pushPathByName('web','baidu') //将name指定的NavDestination页面信息入栈
          })
      }
    }
    .customNavContentTransition((from: NavContentInfo, to: NavContentInfo, operation: NavigationOperation) =>{
      if(operation === 2)
        console.info("customNavContentTransition监听到返回")
      return undefined
    })
    .onNavBarStateChange((isVisible:Boolean)=>{
      console.info("当前状态改变:isVisible",isVisible)
    })
    .title('NavIndex').navDestination(this.PageMap)
  }
}

import { SegmentButton } from '@kit.ArkUI'
import { ItemRestriction, SegmentButtonOptions, SegmentButtonTextItem } from '@ohos.arkui.advanced.SegmentButton'

// PageOne.ets
@Component
export struct PageOneTmp {
  @Consume('pageInfos') pageInfos: NavPathStack;

  @State isShowModal:boolean = false
  @State isShowPanel:boolean = false
  @State tabSelectedIndexes: number[] = [1]
  backF:() => void = () => {}
  @State tabOptions: SegmentButtonOptions = SegmentButtonOptions.tab({
    buttons: [{ text: '最热' }, { text: '最新' }] as ItemRestriction<SegmentButtonTextItem>,
    backgroundColor: '#f8f6f6',
    selectedBackgroundColor: '#f8f6f6',
    backgroundBlurStyle: BlurStyle.NONE
  })

  build() {
    NavDestination() {
      Column () {
        Row(){
          SegmentButton({
            options: this.tabOptions,
            selectedIndexes: $tabSelectedIndexes
          }).width(80).height(25)
        }
        Button('pushPathByName', { stateEffect: true, type: ButtonType.Capsule })
          .width('80%')
          .height(40)
          .margin(20)
          .onClick(() => {
            this.pageInfos.pushPathByName('pageTwo',null )
          })
      }.width('100%').height('100%')
    }.title('pageOne')
    .onBackPressed(() => {
      this.backF()
      const popDestinationInfo = this.pageInfos.pop() // 弹出路由栈栈顶元素
      return false
    })
  }
}

// PageTwo.ets
export class Pages {
  names: string = ""
  values: NavPathStack | null = null
}

@Builder
export function pageTwoTmp(info: Pages) {
  NavDestination() {
    Column () {
      Button('pushPathByName', { stateEffect: true, type: ButtonType.Capsule })
        .width('80%')
        .height(40)
        .margin(20)
        .onClick(() => {
          (info.values as NavPathStack).pushPathByName('pageOne', null)
        })
    }.width('100%').height('100%')
  }.title('pageTwo')
  .onReady((ctx: NavDestinationContext) => {
    console.info("触发pageTwo的")
  })
  .onBackPressed(() => {
    (info.values as NavPathStack).pop()
    return true
  })
}

1. 代码里只是把三种监听方式放一起了，第1种方法传到子页面的会用到onBackPressed，不过这个是多个子页面共用1个监听回调
2. 做拦截的话还是需要到onBackPressed里面做