微信小程序：计算器(附源码)

效果图：

代码实现：

index.js页面：(需要引入一个精确计算)

//引入精确计算的js
const acc = require('../../utils/accurate.js');

Page({
  data: {
    num:'0',
    op:''
  },
  result : null,
  isClear : false,
  numBtn(e){
     var num = e.target.dataset.val;
     if(this.data.num === '0' || this.isClear){
       this.setData({num : num});
       this.isClear = false;
     }else{
       this.setData({num : this.data.num + num});
     }
  },
  opBtn(e){
    var op = this.data.op;
    var num = Number(this.data.num);
    this.setData({op : e.target.dataset.val});
    if(this.isClear){
      return;
    }
    this.isClear = true;
    if(this.result === null){
      this.result = num;
      return;
    }
    if(op === '+'){
      this.result = acc.add(this.result, num);
    } else if(op === '-'){
      this.result = acc.sub(this.result, num);
    } else if(op === '*'){
      this.result = acc.mul(this.result, num);
    } else if(op === '/'){
      this.result = acc.div(this.result, num);
    } else if(op === '%'){
      this.result = this.result % num;
    }
    this.setData({num : this.result + ''});
  },
  dotBtn(e){
    if (this.isClear){
      this.setData({num : '0.'});
      this.isClear = false;
      return;
    }
    if (this.data.num.indexOf('.') >= 0){
      return;
    }
    this.setData({ num : this.data.num + '.'});
  },
  delBtn(e){
    var num = this.data.num.substr(0,this.data.num.length - 1);
    this.setData({ num : num === '' ? '0' : num});
  },
  resetBtn(e){
    this.result = null;
    this.isClear = false;
    this.setData({num : '0',op : ''});
  }
})

精确计算的JS：accurate.js

module.exports = {
  add(arg1,arg2){
    var r1,r2,m;
    try{
      r1 = arg1.toString().split(".")[1].length;
    } catch(e){
      r1 = 0;
    }
    try{
      r2 = arg2.toString().split(".")[1].length;
    } catch(e){
      r2 = 0;
    }
    m = Math.pow(10 , Math.max(r1,r2));
    return (arg1 * m + arg2 * m) / m;
  },
  sub(arg1,arg2){
    var r1,r2,m,n;
    try{
      r1= arg1.toString.split(".")[1].length;
    } catch(e){
      r1 = 0;
    }
    try{
      r2 = arg2.toString().split(".")[1].length;
    } catch(e){
      r2 = 0;
    }
    m = Math.pow(10 , Math.max(r1,r2));
    n = (r1 >= r2)? r1:r2;
    return ((arg1 * m - arg2 * m) / m).toFixed(n);
  },
  mul(arg1,arg2){
    var m = 0,
    s1 = arg1.toString(),
    s2 = arg2.toString();
    try {
      m += s1.split(".")[1].length;
    } catch(e){}
    try {
      m += s2.split(".")[1].length;
    } catch(e){}
    return Number(s1.replace(".","")) * Number(s2.replace(".","")) / Math.pow(10,m);
  },
  div(arg1,arg2){
    var t1 = 0,t2 = 0,r1,r2;
    try {
      t1 = arg1.toString().split(".")[1].length;
    } catch(e){}
    try {
      t2 = arg2.toString().split(".")[1].length;
    } catch(e){}

    r1 = Number(arg1.toString().replace(".",""));
    r2 = Number(arg2.toString().replace(".",""));
    return (r1 / r2) * Math.pow(10,t2 - t1);
  }
}

index.wxml页面：

<view class="result">
  <view class="result-num">{{num}}view>
  <view class="result-op">{{op}}view>
view>
<view class="btns">
  <view>
    <view hover-class="bg" bindtap="resetBtn">Cview>
    <view hover-class="bg" bindtap="delBtn">DELview>
    <view hover-class="bg" bindtap="opBtn" data-val="%">%view>
    <view hover-class="bg" bindtap="opBtn" data-val="/">÷view>
  view>
  <view>
    <view hover-class="bg" bindtap="numBtn" data-val="7">7view>
    <view hover-class="bg" bindtap="numBtn" data-val="8">8view>
    <view hover-class="bg" bindtap="numBtn" data-val="9">9view>
    <view hover-class="bg" bindtap="opBtn" data-val="*">xview>
  view>
  <view>
    <view hover-class="bg" bindtap="numBtn" data-val="4">4view>
    <view hover-class="bg" bindtap="numBtn" data-val="5">5view>
    <view hover-class="bg" bindtap="numBtn" data-val="6">6view>
    <view hover-class="bg" bindtap="opBtn" data-val="-">-view>
  view>
  <view>
    <view hover-class="bg" bindtap="numBtn" data-val="1">1view>
    <view hover-class="bg" bindtap="numBtn" data-val="2">2view>
    <view hover-class="bg" bindtap="numBtn" data-val="3">3view>
    <view hover-class="bg" bindtap="opBtn" data-val="+">+view>
  view>
  <view>
    <view hover-class="bg" bindtap="numBtn" data-val="0">0view>
    <view hover-class="bg" bindtap="dotBtn">.view>
    <view hover-class="bg" bindtap="opBtn" data-val="=">=view>
  view>
view>

index.wxss页面：

page {
  display: flex;
  flex-direction: column;
  height: 100%;
}
.result {
  flex: 1;
  background: #f3f6fe;
  position: relative;
}
.result-num{
  position: absolute;
  font-size: 27pt;
  bottom: 5vh;
  right: 3vw;
}
.result-op{
  font-size: 15pt;
  position: absolute;
  bottom: 1vh;
  right: 3vw;
}
.btns {
  flex: 1;
  display: flex;
  flex-direction: column;
  font-size: 17pt;
  border-top: 1rpx solid #ccc;
  border-left: 1rpx solid #ccc;
}
.btns>view {
  flex: 1;
  display: flex;
}
.btns>view>view {
  flex-basis: 25%;
  border-right: 1rpx solid #ccc;
  border-bottom: 1rpx solid #ccc;
  box-sizing: border-box;
  display: flex;
  align-items: center;
  justify-content: center;
}
.btns>view:last-child>view:first-child {
  flex-basis: 50%;
}
.btns>view:first-child>view:first-child {
  color: #f00;
}
.btns>view>view:last-child {
  color: #fc8e00;
}
.bg {
  background: #eee;
}

index.json：

{
  "navigationBarBackgroundColor": "#fff",
  "navigationBarTitleText": "计算器",
  "navigationBarTextStyle": "black"
}

源码包：

百度网盘链接：https://pan.baidu.com/s/1PTXK0t44kRJ5onVk9leROw
提取码：4d2k