HarmonyOS 自定义dialog样式的时候，dialog弹出之后，底部总有一个空白区域

import { inputMethod } from '@kit.IMEKit'  
import { window } from '@kit.ArkUI'  
@CustomDialog  
struct CustomDialogExample {  
  controller?: CustomDialogController  
  @State @Watch('keyboardHeightChange') keyboardHeight: number = 0  
  @State @Watch('keyboardHeightChange') realKeyboardHeight: number = 0  
  @State offsetY: number = 0  
  aboutToAppear(): void {  
    window.getLastWindow(getContext(this), (err, window) => {  
      window.on("keyboardHeightChange", (keyboardHeight) => {  
        if (keyboardHeight !== 0) {  
          this.keyboardHeight = px2vp(keyboardHeight)  
        }  
      });  
    })  
  }  
  keyboardHeightChange() {  
    if (this.keyboardHeight !== 0 && this.realKeyboardHeight !== 0) {  
      this.offsetY = this.realKeyboardHeight - this.keyboardHeight  
    }  
  }  
  build() {  
    Column() {  
      Text('content')  
        .fontSize(20)  
      TextArea()  
        .width("100%")  
        .height(100)  
      Text('content')  
        .fontSize(20)  
    }  
    .width("100%")  
    .offset({y: this.offsetY})  
    .backgroundColor(Color.White)  
    .borderRadius({topLeft: 32, topRight: 32})  
    .onAreaChange((oldValue: Area, newValue: Area) => {  
      if (Number(oldValue.globalPosition.y) > Number(newValue.globalPosition.y)) {  
        this.realKeyboardHeight = Number(oldValue.globalPosition.y) - Number(newValue.globalPosition.y)  
        console.log("")  
      }  
    })  
  }  
}  
@Entry  
@Component  
struct CustomDialogTest {  
  @State message: string = 'Hello World';  
  dialogController: CustomDialogController = new CustomDialogController({  
    builder: CustomDialogExample(),  
    alignment: DialogAlignment.Bottom,  
    customStyle: true  
  })  
  build() {  
    RelativeContainer() {  
      Text(this.message)  
        .id('HelloWorld')  
        .fontSize(50)  
        .fontWeight(FontWeight.Bold)  
        .alignRules({  
          center: { anchor: 'container', align: VerticalAlign.Center },  
          middle: { anchor: 'container', align: HorizontalAlign.Center }  
        })  
        .onClick(() => {  
          this.dialogController.open()  
        })  
    }  
    .height('100%')  
    .width('100%')  
  }  
}