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超轻量级php框架startmvc

Angular2实现的秒表及改良版示例

更新时间:2020-08-25 13:12:01 作者:startmvc
本文实例讲述了Angular2实现的秒表及改良版。分享给大家供大家参考,具体如下:初版代码

本文实例讲述了Angular2实现的秒表及改良版。分享给大家供大家参考,具体如下:

初版

代码:


export class Watches {
 id: number;
 str: string;
}
export let watcheList: Watches[] = [{
 id: 0, str: '123456'
}, {
 id: 1, str: '564822'
}]
//watchList 是一个静态类
watchList = watcheList;
watchStr: string;
//判断是否是第一次点击startWatch
num: number = 0;
//分 秒 毫秒
minute: number = 0;
second: number = 0;
millisecond: number = 0;
//临时变量 存储计次时的时间,后加入watcheList数组
temp= {
 id: 0,
 str: '0'
};
//定时器的名字
inter: any;
constructor() { }
 resetWatch() {
 //清零
 this.millisecond = 0;
 this.second = 0;
 this.minute = 0;
 this.temp.str = '000000';
 watcheList.length = 0;
 }
timer() {
 //每隔43ms,调用该函数,所以增加43
 this.millisecond = this.millisecond + 43;
 if (this.millisecond >= 1000) {
 this.millisecond = 0;
 this.second = this.second + 1;
 }
 if (this.second >= 60) {
 this.second = 0;
 this.minute = this.minute + 1;
 }
//当小于10是,在前面加一个0,形式则变为00:00:00
 this.watchStr = (this.minute > 10 ? this.minute : '0' + this.minute) + ':'
 + (this.second > 10 ? this.second : '0' + this.second) + ':'
 + (this.millisecond > 10 ? this.millisecond : '0' + this.millisecond);
}
 startWatch(event) {
 this.num = this.num + 1;
 if (this.num > 1) {
 //该状态应该为计次
 temp.id = this.watchList.length;
 temp.str = this.watchStr;
 this.watchList.push(temp);
 } else {
 this.inter = setInterval(() => {
 this.timer();
 }, 43);
 }
 }
 stopWatch(event) {
 this.num = 0;
 if (this.inter) {
 clearInterval(this.inter);
 }
 }
}

原理:

在计时器timer函数里面,定义了一个变量毫秒millisecond,每隔43ms调用timer函数,所以millisecond每次增加43,而后1000ms之后seond增加1,60s之后,minute增加1.

缺点:

函数的运行时间不可控,所以毫秒的增加不准确。

改良版

代码:


// 秒表
export class Watches {
 id: number;
 value: number;
}
export let watcheList: Watches[] = []
export class StopwatchComponent {
 //导入的静态类
 watchList = watcheList;
 //临时变量,用来存贮计次时的时间
 temp: number;
 //判断startWatch是第一次开始,还是计次
 num: number = 0;
 //开始时间
 startTime: number;
 //当前时间
 nowTime: number;
 //时间差
 timerRunner: number = 0;
 //interval函数的名称
 inter: any;
 constructor() { }
 resetWatch() {
 //清零
 this.timerRunner = 0;
 this.watchList.length = 0;
 }
 startWatch(event) {
 this.temp = this.timerRunner;
 //开始计时的时间
 this.startTime = Date.now();
 this.num = this.num + 1;
 if (this.num > 1) {
 //当前状态为计时,将计时的数据加入进watchList
 let watchObj: Watches = {
 id: 0,
 value: 0
 }
 watchObj.id = this.watchList.length;
 watchObj.value = this.timerRunner;
 this.watchList.push(watchObj);
 } else {
 this.inter = setInterval(() => {
 this.nowTime = Date.now();
 this.timerRunner = this.temp + this.nowTime - this.startTime;
 }, 43);
 }
 }
 stopWatch(event) {
 this.num = 0;
 if (this.inter) {
 clearInterval(this.inter);
 }
 }
}

原理:当第一次点击startWatch时,获取当前时间作为开始时间,并每43ms触发定时器,获取最新时间。时间差则为最新时间减去开始时间

PS:这里再为打击推荐一款功能相似的在线工具供大家参考:

在线秒表工具: http://tools.jb51.net/bianmin/miaobiao