HarmonyOS setInterval回调之后@state修饰的变量对应的UI无法更新

参考示例如下：

@Entry
@Component
struct TestPage01 {
  @State timeNum: number = 5
  // 声明定时器
  timer: number = -1

  aboutToAppear(): void {
    this.timer = setInterval(() => {
      if (this.timeNum <= 0) {
        clearInterval(this.timer)
        return
      }
      this.timeNum -= 1
    }, 1000)

  }

  aboutToDisappear(): void {
    clearInterval(this.timer)
  }

  build() {
    Column() {
      Text(this.timeNum.toString())
        .fontSize(50)
    }
    .height('100%')
    .width('100%')
  }
}