HarmonyOS 自定义弹框如何半屏包含安全域

看下这个demo

@CustomDialog
struct CustomDialogExample {
  @Link textValue: string
  controller?: CustomDialogController
  cancel: () => void = () => {
  }
  confirm: () => void = () => {
  }

  build() {
    Column() {
      Text('Change text').fontSize(20).margin({ top: 10, bottom: 10 })
      TextInput({ placeholder: '', text: this.textValue }).width('90%')
        .onChange((value: string) => {
          this.textValue = value
        })
      Text('Whether to change a text?').fontSize(16).margin({ bottom: 10 })
      Flex({ justifyContent: FlexAlign.SpaceAround }) {
        Button('cancel')
          .onClick(() => {
            if (this.controller != undefined) {
              this.controller.close()
              this.cancel()
            }
          }).backgroundColor(0xffffff).fontColor(Color.Black)
        Button('confirm')
          .onClick(() => {
            if (this.controller != undefined) {
              this.controller.close()
              this.confirm()
            }
          }).backgroundColor(0xffffff).fontColor(Color.Red)
      }.margin({ bottom: 10 })
    }
    .backgroundColor(Color.Orange)
    .expandSafeArea([SafeAreaType.SYSTEM], [SafeAreaEdge.BOTTOM])
    .height('40%')
    .borderRadius(20)
  }
}
@Entry
@Component
struct CustomDialogUser {
  @State textValue: string = ''
  dialogController: CustomDialogController | null = new CustomDialogController({
    builder: CustomDialogExample({
      cancel: this.onCancel,
      confirm: this.onAccept,
      textValue: $textValue,
    }),
    cancel: this.exitApp,
    autoCancel: true,
    alignment: DialogAlignment.Bottom,
    gridCount: 4,
    customStyle: true,
    backgroundColor: 0xd9ffffff,
  })

  onCancel() {
    console.info('Callback when the first button is clicked')
  }

  onAccept() {
    console.info('Callback when the second button is clicked')
  }

  exitApp() {
    console.info('Click the callback in the blank area')
  }

  build() {
    Column() {
      Button('点击')
        .onClick(() => {
          if (this.dialogController != null) {
            this.dialogController.open()
          }
        }).backgroundColor(0x317aff)
    }.width('100%').height('100%').backgroundColor(Color.Green)
  }
}