实现微信小程序中的日期选择器效果

Page({
  data: {
    years: [],
    months: [],
    days: [],
    dateIndex: 0
  },
  onLoad: function () {
    // 获取当前年月日
    var datetime = new Date();
    var year = datetime.getFullYear();
    var month = datetime.getMonth() + 1;
    var day = datetime.getDate();

    // 设置年份数组，从当前年往前推 100 年
    var years = [];
    for (var i = year; i >= year - 100; i--) {
      years.push(i);
    }

    // 设置月份数组
    var months = [];
    for (var i = 1; i <= 12; i++) {
      months.push(i);
    }

    // 设置日期数组，根据年月计算出当月的天数
    var days = [];
    var dayCount = this.getDaysOfMonth(year, month);
    for (var i = 1; i <= dayCount; i++) {
      days.push(i);
    }

    // 更新数据
    this.setData({
      years: years,
      months: months,
      days: days
    });
  },
  // 根据年月获取当月的天数
  getDaysOfMonth: function (year, month) {
    var dayCount = 31;
    switch (month) {
      case 2:
        if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
          dayCount = 29;
        } else {
          dayCount = 28;
        }
        break;
      case 4:
      case 6:
      case 9:
      case 11:
        dayCount = 30;
        break;
    }
    return dayCount;
  },
  // 监听日期选择器的 change 事件，更新 dateIndex 变量
  onDateChange: function (e) {
    this.setData({
      dateIndex: e.detail.value
    });
  }
});

Page({
  data: {
    years: [],
    months: [],
    days: [],
    dateIndex: 0
  },
  onLoad: function () {
    // 获取当前年月日
    var datetime = new Date();
    var year = datetime.getFullYear();
    var month = datetime.getMonth() + 1;
    var day = datetime.getDate();

    // 设置年份数组，从当前年往前推 100 年
    var years = [];
    for (var i = year; i >= year - 100; i--) {
      years.push(i);
    }

    // 设置月份数组
    var months = [];
    for (var i = 1; i <= 12; i++) {
      months.push(i);
    }

    // 设置日期数组，根据年月计算出当月的天数
    var days = [];
    var dayCount = this.getDaysOfMonth(year, month);
    for (var i = 1; i <= dayCount; i++) {
      days.push(i);
    }

    // 更新数据
    this.setData({
      years: years,
      months: months,
      days: days
    });
  },
  // 根据年月获取当月的天数
  getDaysOfMonth: function (year, month) {
    var dayCount = 31;
    switch (month) {
      case 2:
        if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
          dayCount = 29;
        } else {
          dayCount = 28;
        }
        break;
      case 4:
      case 6:
      case 9:
      case 11:
        dayCount = 30;
        break;
    }
    return dayCount;
  },
  // 监听日期选择器的 change 事件，更新 dateIndex 变量
  onDateChange: function (e) {
    this.setData({
      dateIndex: e.detail.value
    });
  }
});