微信小程序开发简单计算器（小程序实现计算器功能）

<view class="calculate-box">
  <view class="calculate-txt">{{express}}</view>
  <view class="result-num">={{result}}</view>
</view>
<view class="fixation-box">
  <view class="calculator-box">
    <view class="calculator-line">
      <view data-con='c' class='boxtn btn1 clear' catchtap="clickKeyBoard">AC</view>
      <view data-con='←' class='boxtn btn1' catchtap="clickKeyBoard">
        <image src="../../../images/clear-icon.jpg" alt="微信小程序开发简单计算器（小程序实现计算器功能）" border="0" />

data: {
    express: '', //第一行的表达式
    result: '0', //第二行的结果
    calc2: {
      str: '', //临时字符串
      strList: [], //中缀表达式存储（队列先进先出）
      strListP: [], //后缀表达式（队列先进先出）
      list: [], //存放运算符的堆栈 （先进后出）
      count: [], //计算表达式堆栈（先进后出）
      flag: 0 //表示字符串最后一位是否是运算符号位
    },
    isqr: false,
  },
   //给所有text或view绑定此事件，同时增加对应的自定义属性值
  clickKeyBoard(e) {
    let that = this;
    let input = e.currentTarget.dataset.con //获取每次输入的内容
    if (input == "c") {
      that.handleClear();
    } else if (input == "←") {
      that.handleDelete();
    } else {
      //调用处理字符串
      that.handleInfo(input);

    }


  },

  //处理本地用户的输入操作
  handleInfo(input) {
    if (this.data.calc2.str.length == 0) { //第一次点击
      if (input == "-" || this.checkShuZi(input)) { //为减号
        this.addStr(input);
      } else {
        return;
      }
    } else {
      if (this.data.calc2.flag == 1) { //说明最后一位是符号
        if (this.checkFuHao(input)) {
          this.data.calc2.str = this.data.calc2.str.substring(0, this.data.calc2.str.length - 1); //去掉最后一位符号，添加最新的符号进去
          this.addStr(input);
        } else {
          this.addStr(input);
        }
        console.log();
      } else {
        this.addStr(input);
        this.result();
      }
    }
    this.result();
  },

  //客户点击等号了
  result() {
    //每次点击等号重新把列表给空
    this.data.calc2.strList.length = 0;
    this.data.calc2.strListP.length = 0;
    this.data.calc2.list.length = 0;
    this.data.calc2.count.length = 0;

    //将表达式变成中缀表达式队列
    this.expressToStrList(this.data.express);
    console.log(this.data.calc2.strList);

    //将中缀表达式集合赋值给临时变量
    let tempList = this.data.calc2.strList;
    this.expressToStrListP(tempList);
    console.log(this.data.calc2.strListP);

    //最终的计算
    let tempP = this.data.calc2.strListP
    for (let m in tempP) {
      if (this.checkFuHao2(tempP[m])) { //不含点号的符号方法判断
        let m1 = this.data.calc2.count[0]; //取出第一个数据
        this.data.calc2.count.shift(); //取出后删除该数据
        let m2 = this.data.calc2.count[0];
        this.data.calc2.count.shift();
        // console.log('m1是' +m1);
        // console.log('m2是' + m2);
        // console.log('运算符是' + tempP[m]);
        // console.log('计算结果是：' + this.countDetail(m2, tempP[m], m1));
        this.data.calc2.count.unshift(this.countDetail(m2, tempP[m], m1)); //将计算结果放到count中
      } else {
        this.data.calc2.count.unshift(tempP[m]) //将数字压进去
      }
    }
    console.log('最终的计算结果是' + parseFloat(this.data.calc2.count[0]).toFixed(2));
    this.setData({
      result: this.data.calc2.count[0]
    });
  },

  //实际具体计算
  countDetail(e1, e2, e3) {
    let result = 0.0;
    console.log(e1);
    console.log(e2);
    console.log(e3);
    try {
      if (e2 == "×") {
        if (typeof(e1) != "undefined") {
          result = parseFloat(e1) * parseFloat(e3);
        } else {
          result = parseFloat(e3);
        }
      } else if (e2 == "÷") {
        if (typeof(e1) != "undefined") {
          result = parseFloat(e1) / parseFloat(e3);
        } else {
          result = parseFloat(e3);
        }
      } else if (e2 == "%") {
        if (typeof(e1) != "undefined") {
          result = parseFloat(e1) / parseFloat(e3);
        } else {
          result = parseFloat(e3);
        }
      } else if (e2 == "+") {
        if (typeof(e1) != "undefined") {
          result = parseFloat(e1) + parseFloat(e3);
        } else {
          result = parseFloat(e3);
        }
      } else {
        if (typeof (e1) != "undefined") {
          result = parseFloat(e1) - parseFloat(e3);
        } else {
          result = parseFloat(e3);
        }
      }
    } catch (error) {

    }
    return result;
  },

  //将中缀表达式集合转变为后缀表达式集合
  expressToStrListP(tempList) {
    for (let item in tempList) {
      if (this.checkFuHao2(tempList[item])) { //不含点号的符号方法判断
        if (this.data.calc2.list.length == 0) {
          this.data.calc2.list.unshift(tempList[item]); //直接添加添加运算符
        } else {
          if (this.checkFuHaoDX(this.data.calc2.list[0], tempList[item])) {
            for (let x in this.data.calc2.list) {
              this.data.calc2.strListP.push(this.data.calc2.list[x]); //将运算符都放到listP中
            }
            this.data.calc2.list.length = 0; //循环完把list置空
            this.data.calc2.list.unshift(tempList[item]); //加新元素进去
          } else {
            this.data.calc2.list.unshift(tempList[item]); //直接添加添加运算符
          }
        }
      } else {
        this.data.calc2.strListP.push(tempList[item]); //数字直接加到后缀集合中
      }
    }
    //循环完有可能最后一个是数字了，取到的不是字符，那么运算符里剩余的还的加到listP中
    if (this.data.calc2.list.length > 0) {
      for (let x in this.data.calc2.list) {
        this.data.calc2.strListP.push(this.data.calc2.list[x]); //将运算符都放到listP中
      }
      this.data.calc2.list.length = 0; //循环完把list置空
    }
  },

  //判断两个运算符的优先级(m1是list集合中最后加进去的那个元素比较将要进来的元素，如果m1比m2大，弹出list集合到listp中，再把m2加到list中，否则直接将m2加入list)
  checkFuHaoDX(m1, m2) {
    if ((m1 == "%" || m1 == "×" || m1 == "÷") && (m2 == "-" || m2 == "+")) {
      return true;
    } else {
      return false;
    }
  },

  //将字符串表达式变成中缀队列
  expressToStrList(express) {
    let temp = ''; //定义临时变量
    //将表达式改为中缀队列
    for (let i = 0; i < express.length; i++) {
      if (i == 0 && express[i] == "-") {
        temp = temp + express[i];
      } else {
        if (this.checkShuZi2(express[i])) { //如果i是数字
          temp = temp + express[i];
        } else {
          if (temp.length > 0) {
            if (express[i] == ".") {
              temp = temp + express[i];
            } else {
              this.data.calc2.strList.push(parseFloat(temp));
              temp = '';
              this.data.calc2.strList.push(express[i]);
            }
          } else {
            temp = temp + express[i];
          }
        }
      }
    }
    //循环到最后再看temp中有没有数字了，如果有加进来
    if (temp.length > 0 && this.checkShuZi(temp.substring(temp.length - 1))) {
      this.data.calc2.strList.push(parseFloat(temp));
      temp = '';
    }
  },

  //处理客户输入清除键
  handleClear() {
    this.data.calc2.str = '';
    this.data.calc2.strList.length = 0;
    this.data.calc2.strListP.length = 0;
    this.data.calc2.list.length = 0;
    this.data.calc2.count.length = 0;
    this.data.calc2.minusFlag = 0;
    this.setData({
      express: '',
      result: ''
    });
  },
  //处理客户输入回退键
  handleDelete() {
    let that = this;
    let str = that.data.calc2.str;
    if (str.length > 0) {
      str = str.substring(0, str.length - 1);
      that.data.calc2.str = str;
      that.setData({
        express: str,
      });
    } else {
      return;
    }
  },

  //判断是否是运算符（含点号，用在组织表达式时 .不能重复输入）
  checkFuHao(input) {
    if (input == "-" || input == "+" || input == "÷" || input == "%" || input == "×" || input == ".") {
      return true;
    } else {
      return false;
    }
  },

  //判断是否是运算符（不含点号）
  checkFuHao2(input) {
    if (input == "-" || input == "+" || input == "÷" || input == "%" || input == "×") {
      return true;
    } else {
      return false;
    }
  },

  //判断是否是数字
  checkShuZi(input) {
    if (input == "0" || input == "1" || input == "2" ||
      input == "3" || input == "4" || input == "5" ||
      input == "6" || input == "7" || input == "8" || input == "9") {
      return true;
    } else {
      return false;
    }
  },

  //判断是否是数字(包含.号，用在表达式转中缀方法中)
  checkShuZi2(input) {
    if (input == "0" || input == "1" || input == "2" ||
      input == "3" || input == "4" || input == "5" ||
      input == "6" || input == "7" || input == "8" || input == "9" || input == ".") {
      return true;
    } else {
      return false;
    }
  },

  //给字符串添加新字符(直接追加 在判断是否要改变变量flag)
  addStr(input) {
    this.data.calc2.str = this.data.calc2.str + input;
    if (this.checkFuHao(input)) {
      this.data.calc2.flag = 1; //设置标记位位1
    } else {
      this.data.calc2.flag = 0;
    }
    this.setData({
      express: this.data.calc2.str
    });
  },

/* pages/index/collect-money/collect-money.wxss */

page {
  background-color: #f8f8f8;
}

.bottom-handle {
  height: 100rpx;
  width: 100%;
  display: flex;
  align-items: center;
}

.fixation-box {
  position: fixed;
  bottom: 0;
  width: 750rpx;
}

.sweep-code-verification {
  background: #fff;
  border-top: 1rpx solid #e3e3e3;
  width: 220rpx;
  color: #333;
}

.artificial-collection, .sweep-code-verification {
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  font-size: 24rpx;
  justify-content: center;
}

.artificial-collection {
  background: #f3b055;
  width: 248rpx;
  color: #fff;
}

.payment-code {
  background-image: linear-gradient(203deg, #6f6f6f 0%, #3c3c3c 96%);
  flex: 1;
  font-size: 34rpx;
  color: #fff;
  text-align: center;
  line-height: 100rpx;
}

.sweep-code-verification image {
  width: 40rpx;
  height: 40rpx;
}

.artificial-collection image {
  width: 40rpx;
  height: 40rpx;
}

.calculator-box {
  background-color: #fff;
}

.calculator-line {
  display: flex;
  align-items: center;
}

.boxtn {
  width: 25%;
  height: 154rpx;
  border-left: none;
  display: flex;
  align-items: center;
  justify-content: center;
}

.calculator-box .calculator-line:last-child {
  border-bottom: none;
}

.calculator-line {
  border-bottom: 1rpx solid #dedede;
}

.btn1, .btn2 {
  border-right: 1rpx solid #dedede;
}

.btn2 {
  width: 50%;
}

.equal {
  background: #f3b055;
  font-size: 61rpx;
  color: #fff;
}

.num {
  font-size: 60rpx;
  color: #000;
}

.clear {
  font-size: 48rpx;
  color: #f3b055;
}

.percent {
  font-size: 60rpx;
  color: #000;
}

.charge-content {
  background: #fff;
  border-radius: 24rpx;
  width: 540rpx;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.charge-title {
  background: #f3b055;
  border-radius: 12px 12px 0 0;
  width: 100%;
  height: 92rpx;
  font-size: 34rpx;
  line-height: 92rpx;
  text-align: center;
  color: #fff;
}

.charge-money {
  font-size: 60rpx;
  color: #333;
  line-height: 84rpx;
  margin-top: 35rpx;
}

.charge-propmt {
  font-size: 28rpx;
  color: #999;
  line-height: 42rpx;
  padding-bottom: 40rpx;
}

.charge-btn {
  display: flex;
  align-items: center;
  height: 100rpx;
  border-top: 1rpx solid #ddd;
  width: 100%;
}

.charge-cancel, .charge-confirm {
  flex: 1;
  text-align: center;
  line-height: 100rpx;
  font-size: 34rpx;
}

.charge-cancel {
  color: #999;
  border-right: 1rpx solid #ddd;
}

.charge-confirm {
  color: #f3b055;
}

.successful-content {
  background: #fff;
  border-radius: 24rpx;
  width: 540rpx;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.success-icon {
  width: 120rpx;
  margin-top: 45rpx;
  height: 120rpx;
}

.successful-title {
  font-size: 34rpx;
  color: #333;
  line-height: 42rpx;
  padding: 30rpx 0;
  font-weight: 600;
}

.clear-icon {
  width: 80rpx;
  height: 80rpx;
}

.calculate-box {
  position: fixed;
  top: 0;
  bottom: 875rpx;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  padding: 0 50rpx;
}

.result-num {
  font-size: 88rpx;
  color: #333;
  line-height: 124rpx;
}

.calculate-txt {
  font-size: 60rpx;
  color: #333;
  line-height: 84rpx;
  margin-top: auto;
  word-wrap: break-word;
  text-align: right;
  word-break: break-all;
  text-overflow: -o-ellipsis-lastline;
  overflow: hidden;
  text-overflow: ellipsis;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}
.suspend-box{
  height: 64rpx;
  background-color: rgba(0, 0, 0, .5);
  position: fixed;
  top: 70rpx;
  left: 0;
  color: #fff;
  display: flex;
  align-items: center;
  font-size: 24rpx;
  padding: 0 20rpx;
  border-radius: 0 100rpx 100rpx 0;
  z-index: 9;
}
.close-suspend{
  width: 30rpx;
  height: 30rpx;
}