HarmonyOS 如何实现页面反向传值？

import { router } from '@kit.ArkUI'  
@Entry  
@Component  
export struct AAA {  
  build() {  
    Text("跳转")  
      .onClick(() => {  
        router.pushUrl({  
          url: "/BBB",  
          params: {  
            title: '111',  
            save: (value: string) => {  
              console.log("打印BBB返回的值:", value)  
            }  
          }  
        })  
      })  
  }  
}  
class BBBParams {  
  title: string = ''  
  save?: (value?: string) => void  
}  
@Entry  
@Component  
export struct BBB {  
  @State params: BBBParams = router.getParams() as BBBParams;  
  build() {  
    Column() {  
      Text("返回上一个页面")  
        .onClick(() => {  
          if (this.params.save) {  
            this.params.save("111111")  
          }  
        })  
    }  
  }  
}