案例链接
https://download.csdn.net/download/weixin_45525272/16242325
项目展示
页面设计
分为上面输入的显示部分和下面按键部分
<!--pages/index/index.wxml--> <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">C</view> <view hover-class="bg" bindtap="delBtn">DEL</view> <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">7</view> <view hover-class="bg" bindtap="numBtn" data-val="8">8</view> <view hover-class="bg" bindtap="numBtn" data-val="9">9</view> <view hover-class="bg" bindtap="opBtn" data-val="*">×</view> </view> <view> <view hover-class="bg" bindtap="numBtn" data-val="4">4</view> <view hover-class="bg" bindtap="numBtn" data-val="5">5</view> <view hover-class="bg" bindtap="numBtn" data-val="6">6</view> <view hover-class="bg" bindtap="opBtn" data-val="-">-</view> </view> <view> <view hover-class="bg" bindtap="numBtn" data-val="1">1</view> <view hover-class="bg" bindtap="numBtn" data-val="2">2</view> <view hover-class="bg" bindtap="numBtn" data-val="3">3</view> <view hover-class="bg" bindtap="opBtn" data-val="+">+</view> </view> <view> <view hover-class="bg" bindtap="numBtn" data-val="0">0</view> <view hover-class="bg" bindtap="dotBtn">.</view> <view hover-class="bg" bindtap="opBtn" data-val="=">=</view> </view> </view>
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
// 精确计算 module.exports = { // 加 add: function(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 } // 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m return (arg1 * m + arg2 * m) / m }, // 减 sub: function(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)) //动态控制精度长度 n = (r1 >= r2) ? r1 : r2 return ((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, 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.js
数字点击处理事件
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.val if (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 = true if (this.result === null) { this.result = num return } 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.js const 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.val if (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 = true if (this.result === null) { this.result = num return } 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 = false return } 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 = null this.isClear = false this.setData({ num: '0', op: '' }) } })
