HarmonyOS 实现倒计时功能

@Entry
@Component
struct Arc {
  @State countdownValue: string = '1';

  aboutToAppear(): void {
  }
  build() {
    Flex({ direction: FlexDirection.Column, alignItems: ItemAlign.Center, justifyContent: FlexAlign.Center }) {
      Text(this.countdownValue).backgroundColor(Color.Blue).fontColor(Color.White).width(300).height(45)
        .textAlign(TextAlign.Center)
    }
    .width('100%')
    .height('100%')

  }
  onPageShow(): void {
    setInterval(()=>{
      let target = 1730339780000
      let result = new Date().getTime()
      let dd = target - result
      let days=Math.floor(dd/(24*3600*1000))
      let leave1=dd%(24*3600*1000)    //计算天数后剩余的毫秒数
      let hours=Math.floor(leave1/(3600*1000))
      //计算相差分钟数
      let leave2=leave1%(3600*1000)        //计算小时数后剩余的毫秒数
      let minutes=Math.floor(leave2/(60*1000))
      //计算相差秒数
      let leave3=leave2%(60*1000)      //计算分钟数后剩余的毫秒数
      let seconds=Math.round(leave3/1000)
      console.log('距离结束'+days+'天'+hours+':'+minutes+':'+seconds)
      this.countdownValue = '距离结束'+days+'天'+hours+':'+minutes+':'+seconds;

    }, 1000);

  }
}