HarmonyOS 如何实现让里层view的宽度等于外层view的宽度

可以通过border来实现，参考示例如下：

import { LengthMetrics } from '@kit.ArkUI';

@Entry
@Component
struct Index {
  @State value: string = '登录'
  @State sizeValue: string = ''
  @State message: string = 'Hello World';
  @State dWidth: Length = 0

  build() {
    NavDestination() {
      RelativeContainer() {
        Column() { /// 1号
          Column() { /// 2号
            Divider()
              .height(8)
              .width(this.dWidth)
              .backgroundColor($r("app.color.colorPrimary"))
              .position({
                start: LengthMetrics.px(0),
                end: LengthMetrics.px(0),
                bottom: LengthMetrics.px(0)
              })

            Text('登录')
              .fontColor("#333")
              .fontSize(30)
              .fontWeight(FontWeight.Bold)
              .onAreaChange((oldValue: Area, newValue: Area) => {
                console.info(JSON.stringify(newValue))
                console.log('输出：', newValue)
                console.log('输出：', newValue.width)
                console.log('输出：', typeof newValue.width)
                this.dWidth = newValue.width
              })
          }
          .width("auto")
          .justifyContent(FlexAlign.End)
          .alignItems(HorizontalAlign.Start)
          .margin({
            top: 80,
            left: 10
          })

        }
        .alignItems(HorizontalAlign.Start)
        .backgroundColor($r('app.color.white'))
        .width('100%')
        .height('100%')
        .padding({
          left: '35',
          right: '25'
        })
      }
      .padding({ top: AppStorage.get<number>('statusBarHeight') })
    }
    .hideTitleBar(true)
  }
}