小程序下拉列表框菜单

<view class='top'><view class='top-text'> 选择班别</view><!-- 下拉框 --><view class='top-selected' bindtap='bindShowMsg'><text>{{grade_name}}</text><image src='/images/xia.png'></image></view><!-- 下拉需要显示的列表 --><view class="select_box" wx:if="{{select}}"><view wx:for="{{grades}}" wx:key="unique"><view class="select_one" bindtap="mySelect" data-name="{{item}}">{{item}}</view></view></view>
</view>

/* 顶部 */.top {width: 100vw;height: 80rpx;padding: 0 20rpx;line-height: 80rpx;font-size: 34rpx;border-bottom: 1px solid #000;
}.top-text {float: left;
}/* 下拉框 */.top-selected {width: 50%;display: flex;float: right;align-items: center;justify-content: space-between;border: 1px solid #ccc;padding: 0 10rpx;font-size: 30rpx;
}/* 下拉内容 */.select_box {background-color: #fff;padding: 0 20rpx;width: 50%;float: right;position: relative;right: 0;z-index: 1;overflow: hidden;text-align: left;animation: myfirst 0.5s;font-size: 30rpx;
}.select_one {padding-left: 20rpx;width: 100%;height: 60rpx;position: relative;line-height: 60rpx;border-bottom: 1px solid #ccc;
}/* 下拉过度效果 */@keyframes myfirst {from {height: 0rpx;}to {height: 210rpx;}
}/* 下拉图标 */.top-selected image {height: 50rpx;width: 50rpx;position: absolute;right: 0rpx;top: 20rpx;
}

// pages/zy/zy.js
Page({/*** 页面的初始数据*/data: {select: false,grade_name: '--请选择--',grades: ['1班', '2班', '3班', ]},bindShowMsg() {this.setData({select: !this.data.select})},mySelect(e) {console.log(e)var name = e.currentTarget.dataset.namethis.setData({grade_name: name,select: false})},/*** 生命周期函数--监听页面加载*/onLoad: function(options) {},/*** 生命周期函数--监听页面初次渲染完成*/onReady: function() {},/*** 生命周期函数--监听页面显示*/onShow: function() {},/*** 生命周期函数--监听页面隐藏*/onHide: function() {},/*** 生命周期函数--监听页面卸载*/onUnload: function() {},/*** 页面相关事件处理函数--监听用户下拉动作*/onPullDownRefresh: function() {},/*** 页面上拉触底事件的处理函数*/onReachBottom: function() {},/*** 用户点击右上角分享*/onShareAppMessage: function() {}
})