初版
代碼:
export class Watches {
id: number;
str: string;
}
export let watcheList: Watches[] = [{
id: 0, str: '123456'
}, {
id: 1, str: '564822'
}]
//watchList 是一個靜態類
watchList = watcheList;
watchStr: string;
//判斷是否是第一次點擊startWatch
num: number = 0;
//分 秒 毫秒
minute: number = 0;
second: number = 0;
millisecond: number = 0;
//臨時變量 存儲計次時的時間,後加入watcheList數組
temp= {
id: 0,
str: '0'
};
//定時器的名字
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,調用該函數,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;
}
//當小於10是,在前面加一個0,形式則變爲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) {
//該狀態應該爲計次
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:
在計時器timer函數裏面,定義了一個變量毫秒millisecond,每隔43ms調用timer函數,所以millisecond每次增加43,而後1000ms之後seond增加1,60s之後,minute增加1.
缺點:
函數的運行時間不可控,所以毫秒的增加不準確。
改良版
代碼:
// 秒錶
export class Watches {
id: number;
value: number;
}
export let watcheList: Watches[] = []
export class StopwatchComponent {
//導入的靜態類
watchList = watcheList;
//臨時變量,用來存貯計次時的時間
temp: number;
//判斷startWatch是第一次開始,還是計次
num: number = 0;
//開始時間
startTime: number;
//當前時間
nowTime: number;
//時間差
timerRunner: number = 0;
//interval函數的名稱
inter: any;
constructor() { }
resetWatch() {
//清零
this.timerRunner = 0;
this.watchList.length = 0;
}
startWatch(event) {
this.temp = this.timerRunner;
//開始計時的時間
this.startTime = Date.now();
this.num = this.num + 1;
if (this.num > 1) {
//當前狀態爲計時,將計時的數據加入進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:當第一次點擊startWatch時,獲取當前時間作爲開始時間,並每43ms觸發定時器,獲取最新時間。時間差則爲最新時間減去開始時間