微信小程序评论/留言功能，附：前端+后端代码+视频讲解！

前端界面：

演示：

<!-- 表单 -->
<form bindsubmit="formSubmit">
<input type="text" name="liuyantext" placeholder='输入留言内容' class="input-style"/>
<button formType="submit" class="btn" wx:if="{{nickName == empty}}" open-type="getUserInfo" bindgetuserinfo="bindGetUserInfo" bindtap='login'>授权登录</button>
<button formType="submit" class="btn" wx:else>留言</button>
<input type="text" name="nickname" value='{{nickName}}' style="display:none;"/>
<input type="text" name="headimg" value='{{avatarUrl}}' style="display:none;"/>
</form>

<view wx:for="{{re}}" wx:key="re">
  <view class="result">{{item.result}}</view>
</view>
<view style="text-align:center;font-size:14px;color:#ccc;margin-top:20px;">以下是留言内容</view>
<view wx:for="{{liuyanlist}}" wx:key="liuyanlist" class="liuyanview">
  <view class="headimg"><image src="{{item.headimg}}"></image></view>
  <view class="nickname_liuyantext">
    <view class="nickname">{{item.nickname}} <view class="time">{{item.lytime}}</view></view>
    <view class="text">{{item.liuyantext}}</view>
  </view>
  <!-- 占位符 -->
  <view style="width:100%;height:10px;"></view>
</view>

//index.js
//获取应用实例
const app = getApp()
Page({
  /**
   * 页面的初始数据
   */
  data: {

  },

  //授权登录
  login: function () {
    var that = this;
    // 查看是否授权
    wx.getSetting({
      success(res) {
        if (res.authSetting['scope.userInfo']) {
          // 已经授权，可以直接调用 getUserInfo 获取头像昵称
          wx.getUserInfo({
            success: function (res) {
              console.log(res.userInfo),
                that.setData({
                  nickName: res.userInfo.nickName,
                  avatarUrl: res.userInfo.avatarUrl,
                })
            }
          })
        }
      }
    })
  },
  bindGetUserInfo(e) {
    console.log(e.detail.userInfo)
  },


  formSubmit: function (e) {
    wx.showToast({
      title: '已留言',
      icon: 'success'
    })
    var that = this;
    var liuyantext = e.detail.value.liuyantext; //获取表单所有name=liuyantext的值
    var nickName = e.detail.value.nickname; //获取表单所有name=nickName的值
    var headimg = e.detail.value.headimg; //获取表单所有name=headimg的值
    wx.request({
      url: 'http://localhost/liuyanserver/liuyan.php?liuyantext=' + liuyantext + '&nickname=' + nickName + '&headimg=' + headimg,
      data: {
        liuyantext,
        nickName,
        headimg
      },
      header: { 'Content-Type': 'application/json' },
      success: function (res) {
        console.log(res.data)
        that.setData({
          re: res.data,
        })
        wx.hideToast();
      }
    })
  },

  onPullDownRefresh: function () {
    wx.showNavigationBarLoading();
    var that = this
    wx.request({
      url: 'http://localhost/liuyanserver/loadliuyan.php',
      headers: {
        'Content-Type': 'application/json'
      },
      success: function (res) {
        //将获取到的json数据，存在名字叫list的这个数组中
        that.setData({
          liuyanlist: res.data,
          //res代表success函数的事件对，data是固定的，liuyanlist是数组
        })
        // 隐藏导航栏加载框
        wx.hideNavigationBarLoading();
        // 停止下拉动作
        wx.stopPullDownRefresh();
      }
    })
  },

  //加载最新数据
  onLoad: function () {
    var that = this
    wx.request({
      url: 'http://localhost/liuyanserver/loadliuyan.php',
      headers: {
        'Content-Type': 'application/json'
      },
      success: function (res) {
        //将获取到的json数据，存在名字叫list的这个数组中
        that.setData({
          liuyanlist: res.data,
          //res代表success函数的事件对，data是固定的，liuyanlist是数组
        })
      }
    })
  }
})

/**index.wxss**/
.input-style{
  width: 90%;
  height: 50px;
  border:1px solid #ccc;
  margin:10px auto;
}

.btn{
  width: 88%;
  margin:5px auto;
}

.liuyanview{
  width: 90%;
  margin: 10px auto;
}

.result{
  text-align: center;
  font-size: 14px;
  color: #f00;
  margin-top: 20px;
}

.headimg{
  width: 45px;
  height: 45px;
  border-radius: 100%;
}

.headimg image{
  width: 45px;
  height: 45px;
  border-radius: 100%;
}

.nickname_liuyantext{
  width: calc(100% - 55px);
  float: right;
  margin-top:-45px;
}

.nickname_liuyantext .nickname{
  font-size: 15px;
  color: #999;
}

.nickname_liuyantext .nickname .time{
  font-size: 11px;
  color: #999;
  float: right;
}

.nickname_liuyantext .text{
  font-size: 16px;
  color: #666;
}

后端

https://www.lanzous.com/i1w1deb

数据库格式：