HarmonyOS RelativeContainer的高度变为0, 子组件仍在显示

RelativeContainer() {  
  
  Text('折叠布局')  
    .id('tv')  
  
  RelativeContainer() {  
    Image('')  
      .width(50)  
      .height(50)  
      .id('iv')  
      .alignRules({  
        top: {anchor: "__container__", align: VerticalAlign.Top},  
        bottom: {anchor: "__container__", align: VerticalAlign.Bottom},  
        left: {anchor: "__container__", align: HorizontalAlign.Start},  
        right: {anchor: "__container__", align: HorizontalAlign.End},  
      })  
  
    Text('test')  
      .width(50)  
      .height(50)  
      .id('itemTv')  
      .alignRules({  
        left: {anchor: 'tv', align: HorizontalAlign.Start},  
        right: {anchor: 'tv', align: HorizontalAlign.End},  
        top: {anchor: 'iv', align: VerticalAlign.Bottom},  
      })  
  }  
  .alignRules({  
    left: {anchor: 'tv', align: HorizontalAlign.Start},  
    top: {anchor: 'tv', align: VerticalAlign.Bottom},  
  })  
  .id('expendId')  
}