HarmonyOS 子窗口跳转页面的返回问题

//EntryAbility.ets  
import { UIAbility } from '@kit.AbilityKit';  
import { window } from '@kit.ArkUI';  
export default class EntryAbility extends UIAbility {  
  onWindowStageCreate(windowStage: window.WindowStage): void {  
    windowStage.loadContent("pages/pageA", (err, data) => {  
      //全局使用  
      AppStorage.setOrCreate("windowStage", windowStage);  
    });  
  }  

//pageA.ets  
import window from '@ohos.window'  
import { common, Context } from '@kit.AbilityKit'  
import * as subWin from '../pages/subWindow'; // 导入命名路由页面(子窗口)  
import { BusinessError } from '@kit.BasicServicesKit';  
@Entry  
@Component  
struct pageA {  
  //全局使用  
  @State windowStage: window.WindowStage = AppStorage.get("windowStage") as window.WindowStage  
  @State context: Context = getContext(this) as common.UIAbilityContext;  
  build() {  
    Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {  
      Text('这是 page A').fontSize(20).margin({bottom:10})  
      Button('点击打开子窗口').onClick(()=>{  
        this.windowStage.createSubWindow("mySubWindow", (err, windowClass) => {  
          try {  
            windowClass.loadContentByName(subWin.entryName, (err: BusinessError) => {  
              const errCode: number = err.code;  
              if (errCode) {  
                console.error(`Failed to load the content. Cause code: ${err.code}, message: ${err.message}`);  
                return;  
              }  
              console.info('Succeeded in loading the content.');  
              // 设置子窗口左上角坐标  
              windowClass.moveWindowTo(0, 0)  
              // 展示子窗口  
              windowClass.showWindow();  
              // 设置子窗口全屏化布局避让安全区  
              windowClass.setWindowLayoutFullScreen(false);  
            });  
          } catch (exception) {  
            console.error(`Failed to load the content. Cause code: ${exception.code}, message: ${exception.message}`);  
          }  
        })  
      })  
    }  
    .backgroundColor(Color.Pink).width('100%') .height('100%')  
  }  
}
//subWindow.ets  
import { router } from '@kit.ArkUI';  
export const entryName: string = 'subWindow';  
@Entry({ routeName: entryName })  
@Component  
struct subWindow {  
  build() {  
    Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {  
      Text('这是 子窗口').fontSize(20).margin({bottom:10})  
      Button('点击跳转 Page B')  
        .onClick(() => {  
          router.pushUrl({  
            url: 'pages/pageB'  
          })  
        })  
    }.backgroundColor(Color.Yellow).width('100%') .height('100%')  
  }  
}
//pageB.ets  
import { window } from '@kit.ArkUI'  
@Entry  
@Component  
struct pageB {  
  build() {  
    Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {  
      Text('这是 Page B，请左滑').fontSize(20).margin({bottom:10}).fontColor(Color.White)  
    }.backgroundColor(Color.Green).width('100%') .height('100%')  
  }  
  onBackPress() {//返回时销毁子窗口  
    window.findWindow("mySubWindow").destroyWindow()  
  }  
}