HarmonyOS 展示弹窗的时候，样机底部会有白条。如何隐藏？

onWindowStageCreate(windowStage: window.WindowStage): void { 
 
  AppStorage.setOrCreate("windowStage",windowStage); 
 
  hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onWindowStageCreate'); 
  windowStage.loadContent('pages/Index18', (err, data) => { 
  if (err.code) { 
  hilog.error(0x0000, 'testTag', 'Failed to load the content. Cause: %{public}s', JSON.stringify(err) ?? ''); 
  return; 
} 
 
hilog.info(0x0000, 'testTag', 'Succeeded in loading the content. Data: %{public}s', JSON.stringify(data) ?? ''); 
}); 
}

aboutToAppear() { 
  if (this.dialogController != null) { 
 
    let windowStage = AppStorage.get("windowStage") as window.WindowStage 
    windowStage.getMainWindowSync().setWindowBackgroundColor('#ff00ff'); 
 
    this.dialogController.open(); 
  } 
}

//EntryAbility.ets 
export default class EntryAbility extends UIAbility { 
  // ... 
  onWindowStageCreate(windowStage: window.WindowStage): void { 
    windowStage.loadContent('pages/Index', (err, data) => { 
      if (err.code) { 
        return; 
      } 
      let windowClass: window.Window = windowStage.getMainWindowSync(); // 获取应用主窗口 
      // 1. 设置窗口全屏 
      let isLayoutFullScreen = true; 
      windowClass.setWindowLayoutFullScreen(isLayoutFullScreen) 
        .then(() => { 
          console.info('Succeeded in setting the window layout to full-screen mode.'); 
        }) 
        .catch((err: BusinessError) => { 
          console.error('Failed to set the window layout to full-screen mode. Cause:' + JSON.stringify(err)); 
        }); 
    }); 
  } 
}