微信小程式實現字母索引選單

<view class="container">

<view class="content">
  <view class="all-food">
    <view class="food">全部食物</view>
      <scroll-view class="food-scroll" scroll-y="true" scroll-into-view="{{toView}}" scroll-with-animation="true">
        <view class="food-list">

            <view wx:for="{{foodList}}" wx:key="{{index}}" id="{{'food'+index}}"  data-title="{{item.title}}">
              <view class="nav-text">
                <text>{{item.title}}</text>
              </view>
              <view class="show-food">
                <text wx:for="{{item.lists}}" wx:key="{{index}}">{{item}}</text>
              </view>
            </view>

        </view>
      </scroll-view>
    </view>

  <view class="search-nav"  bindtouchstart="touchStart" bindtouchmove="touchMove" bindtouchend="touchEnd">
    <text bindtap="foodScroll" data-index="{{index}}" wx:for="{{searchNav}}" wx:key="{{index}}">{{item}}</text>
  </view>
</view>
</view>

let foodList = require('../../utils/common');
Page({

  /**
   * 頁面的初始資料
   */
  data: {
    foodList:[],
    toView:'',
    searchNav:[]
  },

  getFoodList(){
        let searchNav = this.data.searchNav
        for(let i in foodList.foodList){
            searchNav.push(foodList.foodList[i].title)
        }
        this.setData({
            foodList:foodList.foodList,
            searchNav:searchNav
        })

  },
  
  foodScroll(e){
        let index = e.currentTarget.dataset.index;
        this.setData({
            toView:`food${index}`
        })

    },
  /**
   * 生命週期函數--監聽頁面載入
   */
  onLoad: function (options) {
    this.getFoodList();
  },

  /**
   * 生命週期函數--監聽頁面初次渲染完成
   */
  onReady: function () {
    
  },

  /**
   * 生命週期函數--監聽頁面顯示
   */
  onShow: function () {
    
  },

  /**
   * 生命週期函數--監聽頁面隱藏
   */
  onHide: function () {
    
  },

  /**
   * 生命週期函數--監聽頁面解除安裝
   */
  onUnload: function () {
    
  },

  /**
   * 頁面相關事件處理常式--監聽使用者下拉動作
   */
  onPullDownRefresh: function () {
    
  },

  /**
   * 頁面上拉觸底事件的處理常式
   */
  onReachBottom: function () {
    
  },

  /**
   * 使用者點選右上角分享
   */
  onShareAppMessage: function () {
    
  }
})

 /* pages/city/city.wxss */
 .container {
  padding: 0 5rpx;
  display: flex;
  justify-content:row;
  background-color: #fff;
}

.content{
  margin-top: 30rpx;
  width: 100%;
}

.food{
  font-size: 40rpx;
  padding-bottom: 10rpx;
  border-bottom: 1rpx solid #fff;
  height:30rpx;
  line-height:30rpx;

}

.food-scroll {
  left: 0;
  position: fixed;
  height: 100%;
  width: 720rpx;
}

.show-food{
  display: flex;
  flex-direction: column;
  justify-content: left;
  
}
.show-food text{
  margin-top: 10rpx;
  margin-bottom: 10rpx;
  font-size: 32rpx;
  border-bottom: 1rpx solid silver;
}

.search-nav{
  position: fixed;
  top: 120rpx;
  bottom: 5rpx;
  right: 5rpx;
  display:flex;
  flex-direction: column;
  justify-content: space-around;
}
.search-nav text{
  text-align: center;
  font-size: 24rpx;
}

let food = [     
  {
      "title":"A",
      "lists":[
      "艾蒿"
        ]
  },
  {
      "title":"B",
      "lists":["白蘿蔔","白瓜","白菜","菠菜","白筍","百合","擯榔","白花菜","白沙蒿","百里香","豆腐柴","芭蕉","菠蘿","白金瓜"
        ]
  },
  {
      "title":"C",
      "lists":["蠶豆","菜花","春筍","慈菇","刺兒菜","草菇","草莓","橙","茶腸","草魚","鯧魚"
        ]
  },
  {
      "title":"D",
      "lists":["豆腐","豆漿","豆腐腦","豆奶","豆汁","豆腐絲","豆腐卷","豆腐皮","豆腐乾","豆乾尖","豆沙","刀豆","豆角","冬瓜","大蒜","大蔥","大白菜","冬寒菜","冬筍","豆瓣菜","大薯","大車前","地膚","大黃","大麻","大紅菇","地衣","蛋清腸"
        ]
  },
  {
      "title":"E",
      "lists":["鵝肉","鵝肝","鵝腿","鵝蛋"]
  },
  {
      "title":"F",
      "lists":["粉絲","腐竹","番茄","方瓜","佛手瓜","分蔥","髮菜"
        ]
      
  },
  {
     "title":"G",
      "lists":["掛麵","甘薯","甘藍","觀達菜","枸杞","柑","桂圓","橄欖","桂魚","鮭魚"]
     
  },
  {
     "title":"H",
      "lists":["花捲","黃豆","花豆","紅蘿蔔","花葉蘿蔔","胡蘿蔔","荷蘭豆","黃豆芽","葫子","葫蘆","葫蘆條","黃瓜","茴香","黑筍","花案菜","槐花","黃麻葉","苦苦菜","猴頭菇","黃菇","海帶","海棠","黃皮果","火腿腸","火雞","火雞肝","火雞腿","黃油","黃鱔","鰉魚","黃骨魚"
       ]
  },
  {
     "title":"J",
      "lists":["豇豆","芥菜頭","節瓜","金瓜","金絲瓜","韭菜","韭黃","韭苔","金針菜","菊筍","茭白","姜","蕨菜","金針菇","雞肉","雞腿","雞心","雞翅","雞腎","雞脖"]
           
  },
  {
     "title":"K",
      "lists":["空鍋餅","苦瓜","苦菜","口蘑","葵花籽"]

  },
  {
     "title":"L",
      "lists":["烙餅","綠豆餅","龍豆","綠豆芽","辣椒","蘿蔔纓","落葵","輪葉黨蔘","羅勒","梨","梅","荔枝","栗子","臘肉","驢肉","驢鞭","驢心","駱駝肉","駱駝掌","駱駝蹄", ]

  },
  {
      "title":"M",
      "lists":["麵條","饅頭","木薯","梅豆","木豆","毛豆","毛筍","馬蹄","馬齒莧","馬蘭頭","麥瓶草",
      "蘑菇","木耳","面蛋","芒果","木瓜","馬肉","馬心"
  ]
  },
  {
     "title":"N",
      "lists":["腦豆","奶茄子","南瓜","牛至","檸檬","牛肉","牛肋","牛腿","牛裡脊","牛蹄筋", "牛鞭","牛肚","牛肝","牛肺","牛腦","牛骨","牛大腸","牛心","牛腎","牛肉乾", "牛肉鬆",
                    ]
  },
  {
   "title":"O",
      "lists":["藕粉","藕"]
  },
  {
     "title":"P",
      "lists":["扁豆","蒲菜","噴瓜","蒲公英","蘋果","葡萄","葡萄乾"]

  },
  {
     "title":"Q",
      "lists":["蕎麥","青豆","茄子","秋葵","青蒜","芹菜","掐不齊","清明菜","球莖茴香","啟明菜葉","青菇"
  ]
  },
  {
     "title":"R",
      "lists":["人蔘果","肉鬆","兒童腸"]
  },
  {
     "title":"S",
      "lists":["燒餅","水面筋","馬鈴薯","素火腿","素大腸","素雞","素雞絲卷","素什錦","四季豆","蛇瓜","絲瓜","筍瓜","蒜苗","生菜","水芹菜","山藥","石頭菜","沙蔘葉","鬆菇","沙果","酸刺","石榴","柿子","柿餅","桑葚"
       ]
           
  },
  {
     "title":"T",
      "lists":["通心麵","甜椒","甜菜葉","茼蒿","湯菜","土三七","苔菜","桃","甜瓜","兔肉"
       ]
  },
  {
   "title":"W",
   "lists":["豌豆","烏菜","萵筍","歪頭菜","梧桐子","無花果","午餐肉"
    ]
  },
  {
     "title":"X",
      "lists":["小豆粥","西葫蘆","小蔥","小白菜","西蘭花","香菜","莧菜","夏枯草","香椿","香茅","小旋花","竹葉菜","香菇","香蕉","西瓜","杏仁","橡子","叉燒肉","鹹肉","香腸"
       ]
           
  },
  {
     "title":"Y",
      "lists":["油餅","油條","油麵筋","薏米","玉米","芸豆","洋蔥","油菜","芋頭","洋姜","野蔥","野韭菜","營野菊口","野蒜","野莧菜","榆錢","魚腥草","羊肚菌","銀耳","櫻桃","柚","楊梅"
       ]
     
  },
  {
      "title":"Z",
      "lists":["竹筍"," 榛子","珍珠白菇","紫菜","棗","豬肉","芝麻","豬大排","豬耳","豬蹄","豬頭","豬肘","豬肺","豬肝","豬腦","豬皮","豬舌","豬腰","豬心","豬血"
       ]
  }
   ]
module.exports = {
   foodList:food
}