HarmonyOS 如何改变光标位置

// xxx.ets  
@Entry  
@Component  
struct TextInputExample {  
  controller: TextInputController = new TextInputController()  
  @State inputValue: string = ""  
  
  // 自定义键盘组件  
  @Builder CustomKeyboardBuilder() {  
    Column() {  
      Row(){  
        Button('x').onClick(() => {  
          // 关闭自定义键盘  
          this.controller.stopEditing()  
        })  
        Button('光标').onClick(() => {  
          // 关闭自定义键盘  
          this.controller.caretPosition(2)  
        })  
      }  
      Grid() {  
        ForEach([1, 2, 3, 4, 5, 6, 7, 8, 9, '*', 0, '#'], (item:number|string) => {  
          GridItem() {  
            Button(item + "")  
              .width(110).onClick(() => {  
              this.inputValue += item  
            })  
          }  
        })  
      }.maxCount(3).columnsGap(10).rowsGap(10).padding(5)  
    }.backgroundColor(Color.Gray)  
  }  
  
  build() {  
    Column() {  
      TextInput({ controller: this.controller, text: this.inputValue })  
        // 绑定自定义键盘  
        .customKeyboard(this.CustomKeyboardBuilder()).margin(10).border({ width: 1 }).height('48vp')  
    }  
  }  
}