WeChat applet implements simple calculator function

WeChat applet: Simple calculator, for your reference, the specific contents are as follows

For those who have just come into contact with mini programs, it is very difficult to get started with a highly practical project. If we want to quickly become familiar with the use of mini programs, we can first try to make a simple calculator.

Run screenshot

The calculator does not have high requirements for the aesthetics of the interface. It is just a combination of some views and button controls, so there is no need to spend a lot of effort on the interface. What is important is the logic layer. The reason why I chose the calculator as the first project is that the logic of the calculator can be simple or complex, and it can fully adapt to the beginners' level of mastery of mini programs.

Main code

js:

Page({
  data: {
   result:"0",
   id1:"clear",
   id2:"back",
   id3:"time",
   id4:"div",
   id5:"mul",
   id6:"sub",
   id7:"add",
   id8:"dot",
   id9:"eql",
   id10:"num_0",
   id11:"num_1",
   id12:"num_2",
   id13:"num_3",
   id14:"num_4",
   id15:"num_5",
   id16:"num_6",
   id17:"num_7",
   id18:"num_8",
   id19:"num_9",
   buttonDot:false,
   is_time:false
  },
  clickButton: function (e) {
   console.log(e);
   var buttonVal = e.target.id;
   var res = this.data.result;
   if(this.data.is_time==true){
    res=0
  }
   var newbuttonDot=this.data.buttonDot;
   var sign;
   if (buttonVal >= "num_0" && buttonVal <= "num_9") {
    var num=buttonVal.split('_')[1];
    if (res == "0" || ((res.length-0) -(length-1)) == "=") {
     res = num;
    }
    else {
     res = res + num;
    }
   }
   else{
    if(buttonVal=="dot")
    {
     if(!newbuttonDot)
     {
      res = res + '.';
     }
    }
    else if(buttonVal=="clear")
    {
     res='0';
    }
    else if(buttonVal=="back")
    {
     var length=res.length;
     if(length>1)
     {
      res=res.substr(0,length-1);
     }
     else{
      res='0'; 
     }
    }
    else if (buttonVal == "div" || buttonVal == "mul" || buttonVal == "sub" || buttonVal == "add")
    {
      if(res.length){}
      else{
        res = JSON.stringify(res)
      }  
      var is_sign=res.substr(res.length-1,res.length)
      if(is_sign=="+"||is_sign=="-"||is_sign=="×"||is_sign=="÷"){
        res=res.substr(0,res.length-1);
      }
     switch(buttonVal){
      case "div":
       sign = '÷';
       break;
      case "mul":
       sign = '×';
       break;
      case "sub":
       sign='-';
       break;
      case "add":
       sign='+';
       break;
     }
     if(!isNaN(res.length))
     {
      res.length-1;
      res=res+sign;
     }
    }
   }
   this.setData({
    is_time:false,
    result: res,
    buttonDot:newbuttonDot,
   });
  },
  equal: function(e){
   var str=this.data.result;
   var item= '';
   var strArray = [];
   var temp=0;
   for(var i=0;i<=str.length;i++){
    var s = str.charAt(i);
    if((s!='' && s>='0' && s<='9') || s=='.'){
     item=item+s;
    }
    else{
     strArray[temp]=item;
     temp++;
     strArray[temp]=s;
     temp++;
     item='';
    }
   }
   if(isNaN(strArray[strArray.length-1]))
   {
    strArray.pop();
   }
   var num;
   var res=strArray[0]*1;
   for(var i=1;i<=strArray.length;i=i+2){
    num=strArray[i+1];
    switch(strArray[i]){
     case "-":
      res = (res-0)-(num-0);
      break;
     case "+":
      res = (res-0) + (num-0);
      break;
     case "×":
      res = (res-0)* (num-0);
      break;
     case "÷":
     if(num!='0')
     {
      res = (res-0)/ (num-0);
     }
     else
     {
      res = '∞';
      break;
     } 
      break;
    }
   }
   this.setData({
    result:res,
   });
  },
  time:function(e){
   var util = require("../../utils/util.js");
   var time = util.formatTime(new Date());
   this.setData({
    result:time,
    is_time:true
   });
  }})

wxml

<!--index.wxml-->
<view class="project_name">Simple Calculator</view>
<view class="screen_content">
  <view class="screen">{{result}}</view>
</view>
<view class="content"> 
 <view class="buttonGroup">
  <button id="{{id1}}" bindtap="clickButton" class="buttonitem color" hover-class="shadow">C</button>
  <button id="{{id2}}" bindtap="clickButton" class="buttonitem color" hover-class="shadow">BS</button>
  <button id="{{id3}}" bindtap="time" class="buttonitem color" hover-class="shadow">
  <icon type="waiting" color="#66CC33"></icon>
  </button>
  <button id="{{id4}}" bindtap="clickButton" class="buttonitem color" hover-class="shadow">÷</button>
 </view> 
 <view class="buttonGroup"> 
  <button id="{{id17}}" bindtap="clickButton" class="buttonitem color" hover-class="shadow">7</button>
  <button id="{{id18}}" bindtap="clickButton" class="buttonitem color" hover-class="shadow">8</button>
  <button id="{{id19}}" bindtap="clickButton" class="buttonitem color" hover-class="shadow">9</button>
  <button id="{{id5}}" bindtap="clickButton" class="buttonitem color" hover-class="shadow">×</button>
 </view>
 <view class="buttonGroup">
  <button id="{{id14}}" bindtap="clickButton" class="buttonitem color" hover-class="shadow">4</button>
  <button id="{{id15}}" bindtap="clickButton" class="buttonitem color" hover-class="shadow">5</button>
  <button id="{{id16}}" bindtap="clickButton" class="buttonitem color" hover-class="shadow">6</button>
  <button id="{{id6}}" bindtap="clickButton" class="buttonitem color" hover-class="shadow">-</button>
 </view>
 <view class="buttonGroup">
  <button id="{{id11}}" bindtap="clickButton" class="buttonitem color" hover-class="shadow">1</button>
  <button id="{{id12}}" bindtap="clickButton" class="buttonitem color" hover-class="shadow">2</button>
  <button id="{{id13}}" bindtap="clickButton" class="buttonitem color" hover-class="shadow">3</button>
  <button id="{{id7}}" bindtap="clickButton" class="buttonitem color" hover-class="shadow">+</button>
 </view>
 <view class="buttonGroup">
  <button id="{{id10}}" bindtap="clickButton" class="buttonitem1 color" hover-class="shadow">0</button>
  <button id="{{id8}}" bindtap="clickButton" class="buttonitem1 color" hover-class="shadow">.</button>
  <button id="{{id9}}" bindtap="equal" class="equal" hover-class="shadow">=</button>
 </view>
</view>

wxss:

/**index.wxss**/
page{
  background: #f5f5f5;
 }
 .project_name{
   position:absolute;
   top:25px;
   width:100%;
   text-align: center;
   font-size: 30px;
 }
 .screen_content{
  position: fixed;
  color: #1b1717;
  background: #fff;
  font-size: 40px;
  bottom: 390px;
  text-align: right;
  height:100px;
  width: 100%;
  word-wrap: break-word;
  border-top:1px solid #a8a8a8;
  border-bottom:1px solid #a8a8a8;
 }
 .screen{
  position: absolute;
  font-size: 40px;
  text-align: right;
  bottom:0px;
  width: 96%;
  left:2%;
  word-wrap: break-word;
 }
 .content{
  position: fixed;
  bottom: 0;
 }
 .buttonGroup{
  display: flex;
  flex-direction: row;
 }
 .buttonitem{
  text-align: center;
  line-height: 120rpx;
  width: 25%;
  border-radius: 0;
 }
 .buttonitem1{
  width: 192rpx;
  text-align: center;
  line-height: 120rpx;
  border-radius: 0;
 }
 icon{
  position: absolute;
  top: 20%;
  left: 67rpx;
 }
 .color{
  background: #fff;
 }
 .equal{
   width: 380rpx;
   text-align: center;
   line-height: 120rpx;
   border-radius: 0;
   background: #fff;
 }
 .shadow{
  background: #e9ebe9;
 }

postscript

I have only given a rough treatment of addition and subtraction here, but such a calculator already has basic functions. As our mastery deepens, we can also add more complex functions such as square and square root, so as to master the development of small programs.

The above is the full content of this article. I hope it will be helpful for everyone’s study. I also hope that everyone will support 123WORDPRESS.COM.

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