微信小程序——获取当天的前一个月至后一个月

// pages/teacher/interview/index.js
Page({

  /**
   * 页面的初始数据
   */
  data: {

  },
  //获取星期
  getWeek(date) {
    let weekArray = [‘日‘, ‘一‘, ‘二‘, ‘三‘, ‘四‘, ‘五‘, ‘六‘];
    return weekArray[date.getDay()];
  },

  //滑动至某个区间时显示当前的月份
  dayScroll(e) {
    const scrollLeftArray = this.data.scrollLeftArray;
    console.log(e.detail.scrollLeft)
    let dayScrollLeft = e.detail.scrollLeft;

    if (dayScrollLeft < scrollLeftArray[0] - 100) {
      this.setData({
        showCurrentMonth: this.data.month
      })
    } else if (this.data.day < 7) {
      if (e.detail.scrollLeft > scrollLeftArray[2] - (7 - this.data.day)*100) {
        this.setData({
          showCurrentMonth: this.data.month + 2
        })
      }
    } else if (this.data.day >= 7){
      if (e.detail.scrollLeft > scrollLeftArray[2]) {
        this.setData({
          showCurrentMonth: this.data.month + 2
        })
      }
    } else {
      this.setData({
        showCurrentMonth: this.data.month + 1
      })
    }
  },

  /**
   * 生命周期函数--监听页面加载
   */
  onLoad: function(options) {
    const _this = this;
    let now = new Date(),
      month = now.getMonth(),
      weekday = _this.getWeek(now),
      day = now.getDate(),
      prevMonth = month==0 ? 11 : month-1,
      nextMonth = month==11 ? 0 : month+1,
      lastDay = new Date((new Date().setMonth(month + 1, 1) - 1000 * 60 * 60 * 24)).getDate(), //获取当月最后一天日期;
      prevLastDay = new Date((new Date().setMonth(month, 1) - 1000 * 60 * 60 * 24)).getDate(); //获取上一个月最后一天日期; 

    let currentMonthDateArray = [], //当前月份的日期和星期的数据集合
      prevMonthDateArray = [], //上月日期和星期的数据集合
      nextMonthDateArray = []; //下月日期和星期的数据集合
    for (let i = 1; i <= lastDay; i++) {
      currentMonthDateArray.push({
        day: i,
        weekDay: _this.getWeek(new Date(new Date().setDate(i)))
      })
    }

    for (let i = day; i <= prevLastDay; i++) {
      prevMonthDateArray.push({
        day: i,
        weekDay: _this.getWeek(new Date(new Date().setMonth(month - 1, i)))
      })
    }

    for (let i = 1; i <= day; i++) {
      nextMonthDateArray.push({
        day: i,
        weekDay: _this.getWeek(new Date(new Date().setMonth(month + 1, i)))
      })
    }
    _this.setData({
      day: day,
      month: month,
      weekday: weekday,
      showCurrentMonth: month + 1,
      prevMonthDateArray: prevMonthDateArray,
      currentMonthDateArray: currentMonthDateArray,
      nextMonthDateArray: nextMonthDateArray
    })

    //获取左边距是为了滑动时改变月份
    const query = wx.createSelectorQuery();
    let scrollLeftArray = [];
    query.selectAll(`#day${month + 1}1, #day${month + 1}${day}, #day${month + 2}1`).boundingClientRect(function(rects) {
      rects.forEach(function(rect) {
        scrollLeftArray.push(rect.left)
      })
      _this.setData({
        scrollLeftArray: scrollLeftArray,
        scrollLeftInit: scrollLeftArray[1] - 100
      })
      console.log(scrollLeftArray)
    }).exec()
  },
})

<view class=‘row day-wrap item-center‘>
  <view class=‘month fs-28 fc-66 shrink‘>
    <text class=‘fs-48‘>{{showCurrentMonth}}</text>月
  </view>
  <view class=‘day-list grow over-hidden‘>
    <scroll-view scroll-x="{{true}}" class=‘day-list-scroll row‘ bindscroll="dayScroll" scroll-left="{{scrollLeftInit}}px">
      <view class="day-item {{prevMonth.weekDay == weekday ? ‘weekday‘ : ‘‘}}" wx:for="{{prevMonthDateArray}}" wx:for-item="prevMonth" id="day{{month}}{{prevMonth.day}}">
        <view class=‘fs-24‘>{{prevMonth.weekDay}}</view>
        <view class=‘fs-32 mt-3‘>{{prevMonth.day}}</view>
      </view>
      <view class="day-item {{currentMonth.day == day ? ‘today‘ : ‘‘}} {{currentMonth.weekDay == weekday ? ‘weekday‘ : ‘‘}}" wx:for="{{currentMonthDateArray}}" wx:for-item="currentMonth" id="day{{month+1}}{{currentMonth.day}}">
        <view class=‘fs-24‘>{{currentMonth.weekDay}}</view>
        <view class=‘fs-32 mt-3‘>{{currentMonth.day}}</view>
      </view>
      <view class="day-item {{nextMonth.weekDay == weekday ? ‘weekday‘ : ‘‘}}" wx:for="{{nextMonthDateArray}}" wx:for-item="nextMonth" id="day{{month+2}}{{nextMonth.day}}">
        <view class=‘fs-24‘>{{nextMonth.weekDay}}</view>
        <view class=‘fs-32 mt-3‘>{{nextMonth.day}}</view>
      </view>
    </scroll-view>
  </view>
</view>

.day-wrap{
  background-color: #fff;
  padding-top: 10px;
  padding-bottom: 10px;
}
.month{
  padding: 0 15px;
}

.day-list-scroll{
  white-space:nowrap;
}
.day-item{
  padding: 2px 8px;
  margin-right:15px;
  text-align: center;
  display: inline-block;
  vertical-align: middle
}
.day-item.weekday{
  background-color: #f2f2f2;
}
.day-item.today{
  background-color: #ffdee8;
  color: #ff5e2f
}