HarmonyOS 富文本组件RichEditor怎么实现输入文本替换为图片？（API12+）

 @Entry
@Component
struct Index {
  controller: RichEditorController = new RichEditorController();
  @State pictureName: string = ''
  @State start: number = 0
  // 当前是否输入@符号
  @State flag: boolean = false
  // 存放图片名称
  imageList: Array<string> = ['logo', 'startIcon']

  build() {
    Column() {
      RichEditor({ controller: this.controller })
        .aboutToIMEInput((value: RichEditorInsertValue) => {
          if (value.insertValue.includes("start")) {
            this.controller.deleteSpans({ start: this.start, end: this.controller.getCaretOffset() })
            this.controller.addImageSpan($r('app.media.startIcon'))
            this.start=this.controller.getCaretOffset()
            return false
          }
          this.start=this.controller.getCaretOffset()
          return true
        })
        .width("98%")
        .height("30%")
        .borderWidth(1)
    }
    .width("100%")
    .height("100%")
  }
}