微信小程序数学公式（微信小程序计算器实例详解）

<view class="content">
    <view class="num">{{num}}</view>
    <view class="operotor">{{op}}</view>
</view>
<view class="entry">
    <view>
        <view class="item" bindtap="resetBtn">c</view>
        <view class="item" bindtap="delBtn">DEL</view>
        <view class="item" bindtap="opBtn" data-val="%">%</view>
        <view class="item" bindtap="opBtn" data-val="/">÷</view>
    </view>
    <view>
        <view class="item" bindtap="numBtn" data-val="7">7</view>
        <view class="item" bindtap="numBtn" data-val="8">8</view>
        <view class="item" bindtap="numBtn" data-val="9">9</view>
        <view class="item" bindtap="opBtn" data-val="*">x</view>
    </view>
    <view>
        <view class="item" bindtap="numBtn" data-val="4">4</view>
        <view class="item" bindtap="numBtn" data-val="5">5</view>
        <view class="item" bindtap="numBtn" data-val="6">6</view>
        <view class="item" bindtap="opBtn" data-val="-">-</view>
    </view>
    <view>
        <view class="item" bindtap="numBtn" data-val="1">1</view>
        <view class="item" bindtap="numBtn" data-val="2">2</view>
        <view class="item" bindtap="numBtn" data-val="3">3</view>
        <view class="item" bindtap="opBtn" data-val="+">+</view>
    </view>
    <view>
        <view class="item tow" bindtap="numBtn" data-val="0">0</view>
        <view class="item one" bindtap="dotBtn" data-val=".">.</view>
        <view class="item one" bindtap="opBtn" data-val="=">=</view>
    </view>
</view>

page {
  display: flex;
  flex-direction: column;
  height: 100%;
}
.content {
  flex: 1;
  background-color: #f3f6fe;
  position: relative;
}
.content .num {
  position: absolute;
  font-size: 27pt;
  bottom: 5vh;
  right: 3vw;
}
.content .operotor {
  font-size: 15pt;
  position: absolute;
  bottom: 1vh;
  right: 3vw;
}
.entry {
  flex: 1;
  font-size: 17pt;
  border-top: 1rpx solid #ccc;
}
.entry .item {
  flex: 1;
  padding: 30rpx 0;
  text-align: center;
  flex-basis: 25%;
  border-left: 1rpx solid #ccc;
  border-bottom: 1rpx solid #ccc;
}
.entry > view {
  display: flex;
}
.entry > view .tow {
  flex: 2;
}
.entry > view .one {
  flex: 1;
}

Page({
    data: {
        num: "",  // 存储数字
        op: ""    //存储运算符
    },
    result: null,  
    isClear: false,

    numBtn: function(e) {
        var num = e.target.dataset.val
            //console.log(num) 得到data-val的值
        console.log(this.isClear)
        if (this.data.num === "0" || this.isClear) {
            this.setData({ num: num })
            this.isClear = false
        } else {
            this.setData({ num: this.data.num + num })
        }
    },

    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 = this.result + num
        } else if (op === "-") {
            this.result = this.result - num
        } else if (op === "*") {
            this.result = this.result * num
        } else if (op === "/") {
            this.result = this.result / num
        } else if (op === "%") {
            this.result = this.result % num
        }
        this.setData({ num: this.result })
    },

    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 + "." })
    },
    delBtn: function() {

        var num = this.data.num.substr(0, this.data.num.length - 1)
        this.setData({ num: num === "" ? "0" : num })
    },
    resetBtn: function() {
        this.result = null
        this.isClear = false
        this.setData({ num: "0", op: "" })
    }
})