需求：实现一个时间打卡签到按钮。

实现方法：每隔一秒钟获取一下当前时间。

实现代码如下：

Column(){Text(this.curTime).fontColor('#FFFFFF').fontWeight(600).fontSize('32vp')Text('上班打卡').fontColor('#FFFFFF')
}
.width('170vp')
.height('170vp')
.justifyContent(FlexAlign.Center)
.alignItems(HorizontalAlign.Center)
.backgroundImage($r('app.media.check_signin'))
.backgroundImageSize({ width: StyleConstants.FULL_PARENT,height: StyleConstants.FULL_PARENT })

@State curTime:string | null = null;
@State time:number | null = null;

// 更新时间
updateTime(){const now = new Date();const hours = String(now.getHours()).padStart(2, '0');const minutes = String(now.getMinutes()).padStart(2, '0');const time = `${hours}:${minutes}` as string;this.curTime = time;
}

aboutToAppear():void {this.updateTime();// 每秒更新一次时间this.time = setInterval(()=>{this.updateTime()}, 1000);
}
aboutToDisappear():void {// 清除定时器clearInterval(this.time)
}