1. 按下+1按钮，系统会自动加一并显示：
2. 按下-1按钮，系统会自动减一并显示：
3. 按下*2按钮，系统会自动乘二并显示：
4. 按下/2按钮，系统会自动除以二并显示:

根据上述基本操作，可以实现类似于计算器的功能。

in.js

Page({

  /**
   * 页面的初始数据
   */
  data: {
    num:0   //设定初值，方便在页面上显示
  },

  onLoad: function (options) {

  },

  inc1: function(event){
      var that=this
      this.setData({
        num:that.data.num+1
      })
  },

  dec1: function(event){
    var that=this
    this.setData({
      num:that.data.num-1
    })    
  },

  mul2: function(event){
    var that=this
    this.setData({
      num:that.data.num*2
    })
  },

  div2: function(event){
    var that=this
    this.setData({
      num:that.data.num/2
    })
  },
})

in.json

{
  "usingComponents": {}
}

in.wxml

<view class="background">
      <text class="title">{{num}}</text>
      <!-- <text class="text">{{infomation}}</text> -->
</view>
<view class="btn1">
    <text bindtap="inc1">加一</text>
</view>
<view class="btn2">
    <text bindtap="dec1">减一</text>
</view>
<view class="btn3">
    <text bindtap="mul2">乘二</text>
</view>
<view class="btn4">
    <text bindtap="div2">除二</text>
</view>

in.wxss

.background{
  display: flex;
  flex-direction: column;
  justify-content: center;
  background-color: rgb(255, 255, 255);
  width: 90%;
  border-radius: 20rpx;
  margin-top: 50rpx;
  margin-left: auto;
  margin-right: auto;
  box-shadow:0rpx 0rpx 20rpx 1rpx gray;
}

.title{
  margin: auto;
  margin-top: 50rpx;
  color: red;
  font-size: 130%;
}

.btn1{
  font-size: 13pt;
  height: 55rpx;
  background: #7B68EE;
  color: black;
  text-align: center;
  border-radius: 50px;
  margin: 10% 20% 10% 20%;
}

.btn2{
  font-size: 13pt;
  height: 55rpx;
  background: #00FA9A;
  color: black;
  text-align: center;
  border-radius: 50px;
  margin: 10% 20% 10% 20%;
}

.btn3{
  font-size: 13pt;
  height: 55rpx;
  background: #F0E68C;
  color: black;
  text-align: center;
  border-radius: 30px;
  margin: 10% 20% 10% 20%;
}

.btn4{
  font-size: 13pt;
  height: 55rpx;
  background:   #FF4500;
  color: black;
  text-align: center;
  border-radius: 30px;
  margin: 10% 20% 10% 20%;
}