HarmonyOS 开发一个聊天应用，输入框在底部，如何处理键盘弹起整个页面被顶起的问题，有没有DEMO啊

onWindowStageCreate(windowStage: window.WindowStage): void { 
  // Main window is created, set main page for this ability 
  hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onWindowStageCreate'); 
  windowStage.loadContent('pages/ChildPage', (err, data) => { 
  let a = windowStage.getMainWindowSync().getUIContext().getKeyboardAvoidMode(); 
  // 设置虚拟键盘抬起时把页面上抬直到露出光标 
  windowStage.getMainWindowSync().getUIContext().setKeyboardAvoidMode(KeyboardAvoidMode.OFFSET); 
  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) ?? ''); 
}); 
 
}
@Entry 
@Component 
struct SafeAreaExample { 
  @State text: string = '' 
  controller: TextInputController = new TextInputController() 
 
  build() { 
    Row() { 
      Stack() { 
        Column() 
          .height('100%').width('100%') 
          .backgroundColor(Color.Green) 
          .expandSafeArea([SafeAreaType.KEYBOARD, SafeAreaType.SYSTEM]) 
        Column() { 
          Button('Set caretPosition 1') 
            .onClick(() => { 
              this.controller.caretPosition(1) 
            }) 
          TextArea({ text: this.text, placeholder: 'input your word...', controller: this.controller }) 
            .placeholderFont({ size: 14, weight: 400 }) 
            .width(320).height(40).offset({y: 120}) 
            .fontSize(14).fontColor(Color.Black) 
            .backgroundColor(Color.White) 
        }.width('100%').alignItems(HorizontalAlign.Center) 
      } 
    }.height('100%') 
  } 
}