微信小程序实现计算器案例微信小程序实现计算器案例

本文实例为大家分享了微信小程序实现计算器的具体代码，供大家参考，具体内容如下
项目展示

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页面设计
分为上面输入的显示部分和下面按键部分

{{num}}{{op}}CDEL%÷789×456-123+0.=

页面样式

/* pages/index/index.wxss */page {display: flex; flex-direction: column; height: 100%; color: #555; }.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; }/* 按钮样式 */.bg {background: rgb(223, 44, 20); }.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; }

页面逻辑
util–>calc.js
计算过程是将小数都乘以两数10的最大次幂化为整数，这样可进行高精度计算，最后再将得数除以相应的10的次幂
例如

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// 精确计算module.exports = {// 加add: function(arg1, arg2) {var r1, r2, mtry {r1 = arg1.toString().split(".")[1].length} catch (e) {r1 = 0}try {r2 = arg2.toString().split(".")[1].length} catch (e) {r2 = 0}// 将小数都化为整数在进行计算m是需要×的10的幂数m = Math.pow(10, Math.max(r1, r2))// 最后返回的时候再除以mreturn (arg1 * m + arg2 * m) / m},// 减sub: function(arg1, arg2) {var r1, r2, m, ntry {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))//动态控制精度长度n = (r1 >= r2) ? r1 : r2return ((arg1 * m - arg2 * m) / m).toFixed(n)},// 乘mul: function(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)},// 除div: function(arg1, arg2) {var t1 = 0,t2 = 0,r1, r2try {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.js

数字点击处理事件
【微信小程序实现计算器案例】当点击数字不为零，并且指示不清空时候，将输入的num拼接到page里的num

// 数字按钮事件处理函数numBtn: function(e) {var num = e.target.dataset.valif (this.data.num === '0' || this.isClear) {this.setData({num: num})this.isClear = false} else {this.setData({num: this.data.num + num})}},

运算符处理事件

// 运算符事件处理函数opBtn: function(e) {var op = this.data.op// 获取之前的数var num = Number(this.data.num)this.setData({op: e.target.dataset.val})if (this.isClear) {return}this.isClear = trueif (this.result === null) {this.result = numreturn}if (op === '+') {this.result = calc.add(this.result, num)} else if (op === '-') {......其他运算操作（详细代码看下面完整代码部分）......}this.setData({num: this.result + ''})},

全部js

// pages/index/index.jsconst calc = require('../../utils/calc.js')Page({/*** 页面的初始数据*/data: {num: '0',op: ''},// 结果result: null,// 是否清空数字行/*清空的情况(值为true)点击过运算符之后,改为true 以便下一次输入数字显示点击清空*/isClear: false,// 数字按钮事件处理函数numBtn: function(e) {var num = e.target.dataset.valif (this.data.num === '0' || this.isClear) {this.setData({num: num})this.isClear = false} else {this.setData({num: this.data.num + num})}},// 运算符事件处理函数opBtn: function(e) {var op = this.data.op// 获取之前的数var num = Number(this.data.num)this.setData({op: e.target.dataset.val})if (this.isClear) {return}this.isClear = trueif (this.result === null) {this.result = numreturn}if (op === '+') {this.result = calc.add(this.result, num)} else if (op === '-') {this.result = calc.sub(this.result, num)} else if (op === '*') {this.result = calc.mul(this.result, num)} else if (op === '/') {this.result = calc.div(this.result, num)} else if (op === '%') {this.result = this.result % num}this.setData({num: this.result + ''})},// 小数点事件处理函数dotBtn: function() {if (this.isClear) {this.setData({num: '0.'})this.isClear = falsereturn}if (this.data.num.indexOf('.') >= 0) {return}this.setData({num: this.data.num + '.'})},// DEL按钮处理函数delBtn: function() {var num = this.data.num.substr(0, this.data.num.length - 1)this.setData({num: num === '' ? '0' : num})},// C按钮事件处理函数resetBtn: function() {this.result = nullthis.isClear = falsethis.setData({num: '0',op: ''})}})

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