微信小程序 倒计时组件实现代码

function countdown(that) { var second = that.data.second if (second == 0) {  // console.log("Time Out...");  that.setData({   second: "Time Out..."  });  return ; } var time = setTimeout(function(){  that.setData({   second: second - 1  });  countdown(that); } ,1000)}Page({  data: {    second: 3  },  onLoad: function() {    countdown(this);  }});

/* 秒级倒计时 */function countdown(that) { var second = that.data.second if (second == 0) {  that.setData({   second: "Time out!",   micro_second: "micro_second too."  });  clearTimeout(micro_timer);  return ; } var timer = setTimeout(function(){  that.setData({   second: second - 1  });  countdown(that); } ,1000)}/* 毫秒级倒计时 */// 初始毫秒数，同时用作归零var micro_second_init = 100;// 当前毫秒数var micro_second_current = micro_second_init;// 毫秒计时器var micro_timer;function countdown4micro(that) { if (micro_second_current <= 0) {  micro_second_current = micro_second_init; } micro_timer = setTimeout(function(){  that.setData({   micro_second: micro_second_current - 1  });  micro_second_current--;  countdown4micro(that); } ,10)}Page({  data: {    second: 2,    micro_second: micro_second_init  },  onLoad: function() {    countdown(this);    countdown4micro(this);  }});

<text style="display: block;">second: {{second}}s</text><text>{{micro_second}}</text>

function dateformat(second) {  var dateStr = "";  var hr = Math.floor(second / 3600);  var min = Math.floor((second - hr * 3600) / 60);  var sec = (second - hr * 3600 - min * 60);// equal to => var sec = second % 60;  dateStr = hr + ":" + min + ":" + sec;  return dateStr;}目前有2个时钟，影响性能，合并下去掉countdown，于是countdown4micro变成以下的样子：function countdown4micro(that) {  var loop_second = Math.floor(loop_index / 100);  // 得知经历了1s  if (cost_micro_second != loop_second) {    // 赋予新值    cost_micro_second = loop_second;    // 总秒数减1    total_second--;  }   // 每隔一秒，显示值减1; 渲染倒计时时钟  that.setData({   clock:dateformat(total_second - 1)  });   if (total_second == 0) {    that.setData({     // micro_second: "",     clock:"时间到"    });    clearTimeout(micro_timer);    return ;   }   if (micro_second_current <= 0) {  micro_second_current = micro_second_init; } micro_timer = setTimeout(function(){  that.setData({   micro_second: micro_second_current - 1  });  micro_second_current--;  // 放在最后++，不然时钟停止时还有10毫秒剩余  loop_index ++;  countdown4micro(that); } ,10)}

/**  * 需要一个目标日期，初始化时，先得出到当前时间还有剩余多少秒 * 1.将秒数换成格式化输出为XX天XX小时XX分钟XX秒 XX * 2.提供一个时钟，每10ms运行一次，渲染时钟，再总ms数自减10 * 3.剩余的秒次为零时，return，给出tips提示说，已经截止 */// 定义一个总毫秒数，以一分钟为例。TODO，传入一个时间点，转换成总毫秒数var total_micro_second = 2 * 1000;/* 毫秒级倒计时 */function countdown(that) {   // 渲染倒计时时钟   that.setData({     clock:dateformat(total_micro_second)   });   if (total_micro_second <= 0) {     that.setData({       clock:"已经截止"     });     // timeout则跳出递归     return ;   }     setTimeout(function(){    // 放在最后--    total_micro_second -= 10;    countdown(that);  }  ,10)}// 时间格式化输出，如3:25:19 86。每10ms都会调用一次function dateformat(micro_second) {   // 秒数   var second = Math.floor(micro_second / 1000);   // 小时位   var hr = Math.floor(second / 3600);   // 分钟位   var min = Math.floor((second - hr * 3600) / 60);   // 秒位  var sec = (second - hr * 3600 - min * 60);// equal to => var sec = second % 60;  // 毫秒位，保留2位  var micro_sec = Math.floor((micro_second % 1000) / 10);  return hr + ":" + min + ":" + sec + " " + micro_sec;}Page({  data: {    clock: ''  },  onLoad: function() {    countdown(this);  }});