小程序案例：计算器

功能介绍

加（+）减（-）乘（×）除（÷）

取余（%）

Delete删除

C全部清空

实操代码

WXML

<!--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>

WXSS

/* 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: #eee;
}

.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;
}

效果图

JS代码

// pages/index/index.js
const calc = require('../../utils/calc.js')

Page({

  /**
   * 页面的初始数据
   */
  data: {
    num: '0',
    op: ''
  },

  result: null,
  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
    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: ''
    })
  }
})