HarmonyOS 如何实现点击按钮收起键盘(键盘收起同时TextInput失去焦点)

import promptAction from '@ohos.promptAction' 
@Entry 
@Component 
struct TextInputExample { 
  @State text: string = '' 
  controller: TextInputController = new TextInputController() 
  build() { 
    Column() { 
      TextInput({ text: this.text, placeholder: '请输入用户名', controller: this.controller }) 
        .height(40) 
        .margin(20) 
        .fontSize(14) 
        .width('90%') 
      Button('弹出toast') 
        .onClick(() => { 
          // 焦点转移到button上 
          focusControl.requestFocus('button') 
          promptAction.showToast({ 
            message: '我是toast', 
            duration: 2000 
          }) 
        }).width('30%').key('button') 
    } 
    .width('100%') 
    .height('100%') 
  } 
}