HarmonyOS RelativeContainer容器的宽高如何根据子组件确定

build() {  
  Stack(){  
    Stack(){  
      RelativeContainer() {  
        Text('123')  
          .id('tv')  
          .alignRules({  
            // top: {anchor: "__container__", align: VerticalAlign.Top},  
            left: {anchor: "__container__", align: HorizontalAlign.Start},  
          })  
          .height(100)  
          .width(200)  
      }  
      .width('auto')  
      .height('auto')  
      .backgroundColor(Color.Blue)  
    }  
  }  
}