HarmonyOS 关于状态管理

@Entry 
@ComponentV2 
struct Index { 
  @Local numArr: number[] = [1,2,3,4,5]; 
 
  build() { 
    Column() { 
      ForEach(this.numArr, (item: number) =>{ 
        VideDemo({num: item}) 
      }) 
    } 
  } 
} 
@ComponentV2 
struct VideDemo { 
  num: number = 0; 
  build() { 
    Row(){ 
      Text("hahha:" + this.num) 
    } 
  } 
}
@ObservedV2 
class Info { 
  @Trace name: string; 
  @Trace age: Resource = $r('app.media.startIcon') 
  constructor(name: string, age: Resource) { 
    this.name = name; 
    this.age = age; 
  } 
} 
@Entry 
@ComponentV2 
struct Index { 
  @Local info: Info = new Info("Tom", $r('app.media.background')); 
  build() { 
    Column() { 
      Text(`Parent info.name ${this.info.name}`) 
      Image(this.info.age) 
        .width(40) 
        .height(40) 
    } 
  } 
}