HarmonyOS @ObjectLink和@State的相关疑问

子组件使用@ObjectLink接收来自父组件中用@State 修饰的@Observed的嵌套变量对象，当该对象的嵌套对象属性发生修改时子组件无法刷新UI

demo：

@Observed  
class Model {  
  a: A  
  constructor(a: A) {  
    this.a = a  
  }  
}  
  
@Observed  
class A {  
  str: string  
  constructor(str: string) {  
    this.str = str  
  }  
}  
  
@Component  
struct MyView {  
  @ObjectLink objLink: Model  
  build() {  
    Text(`MyView ${this.objLink.a.str}`)  
  }  
}  
  
@Entry  
@Component  
struct Index {  
  @State model: Model = new Model(new A("b"))  
  build() {  
    Column({ space: 20 }) {  
      MyView({ objLink: this.model})  
      Button("Click")  
        .onClick(() => {  
          this.model.a.str = "d"  
        })  
    }  
    .width("100%")  
    .height("100%")  
  }  
}

HarmonyOS

zbw_apple

2024-10-24 13:12:48

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回答 1

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回答 1

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Heiang

1.当前您demo里面传入到ChatItemView里面的是Chat，那你观测的只是Chat，Chat下面的嵌套对象user是观测不到的。

2.ChatItemView子组件正确传入的是user: this.chat.user，从而子组件观测的就是user。

@Observed  
class Chat {  
  user: User  
  content:string  
  constructor(user: User, content:string) {  
    this.user = user  
    this.content = content  
  }  
}  
  
@Observed  
class User {  
  avatar: string  
  
  constructor(str: string) {  
    this.avatar = str  
  }  
}  
  
@Component  
struct ChatItemView {  
  @ObjectLink user: User  
  @ObjectLink chat: Chat  
  build() {  
    Column() {  
      Text(`ChatItemView ${this.user.avatar}`)  
      Text(`ChatItemView ${this.chat.content}`)  
      Button("Click")  
        .onClick(() => {  
          this.user.avatar = "http:sxxxxxxx"  
          this.chat.content= '变化了'  
        })  
    }  
  }  
}  
   
@Entry  
@Component  
struct Index {  
  @State chat: Chat = new Chat(new User("http:sxxxx"),'试试看')  
  
  build() {  
    Column({ space: 20 }) {  
      ChatItemView({ user: this.chat.user,chat:this.chat})  
      Button("Click")  
        .onClick(() => {  
          this.chat.user.avatar = "http:sx"  
          // this.chat.content= '变化了'  
        })  
    }  
    .width("100%")  
    .height("100%")  
  }  
}

2024-10-24 15:11:33

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