【微信小程序】手写索引选择器（城市列表，汽车品牌选择列表）

摘要： 小程序索引选择器，点击跳转相应条目，索引可滑动，滑动也可跳转

场景：城市选择列表， 汽车品牌选择列表

所用组件： scroll-view（小程序原生） 

所用api： wx.getsysteminfo     https://developers.weixin.qq.com/miniprogram/dev/api/base/system/system-info/wx.getsysteminfo.html

使用技术： 组件 + api + 一个简单的计算

效果示意：

 

 

本例数据结构：（你可以把你的数据改成这种结构，当然，掌握方法后可自行调整）

  1 list: [
  2             {
  3               "letter": "a",
  4               "list": [{
  5                 "name": "奥迪1",
  6                 "id": 1
  7               },
  8               {
  9                 "name": "奥迪2",
 10                 "id": 2
 11               }]
 12             },
 13             {
 14               "letter": "b",
 15               "list": [{
 16                 "name": "宝马1",
 17                 "id": 3
 18               },
 19               {
 20                 "name": "宝马2",
 21                 "id": 4
 22               }]
 23             },
 24             {
 25               "letter": "c",
 26               "list": [{
 27                 "name": "麻喇沙底",
 28                 "id": 5
 29               },
 30               {
 31                 "name": "adidas",
 32                 "id": 6
 33               }]
 34             },
 35             {
 36               "letter": "d",
 37               "list": [{
 38                 "name": "煲事件",
 39                 "id": 7
 40               },
 41               {
 42                 "name": "保时捷",
 43                 "id": 8
 44               }]
 45             },
 46             {
 47               "letter": "e",
 48               "list": [{
 49                 "name": "宝马1",
 50                 "id": 9
 51               },
 52               {
 53                 "name": "宝马2",
 54                 "id": 10
 55               }]
 56             },
 57             {
 58               "letter": "f",
 59               "list": [{
 60                 "name": "宝马1",
 61                 "id": 11
 62               },
 63               {
 64                 "name": "宝马2",
 65                 "id": 12
 66               }]
 67             },
 68             {
 69               "letter": "g",
 70               "list": [{
 71                 "name": "宝马1",
 72                 "id": 15
 73               },
 74               {
 75                 "name": "宝马2",
 76                 "id": 16
 77               }]
 78             },
 79             {
 80               "letter": "h",
 81               "list": [{
 82                 "name": "宝马1",
 83                 "id": 17
 84               },
 85               {
 86                 "name": "宝马2",
 87                 "id": 18
 88               }]
 89             },
 90             {
 91               "letter": "i",
 92               "list": [{
 93                 "name": "宝马1",
 94                 "id": 19
 95               },
 96               {
 97                 "name": "宝马2",
 98                 "id": 20
 99               }]
100             },
101             {
102               "letter": "j",
103               "list": [{
104                 "name": "宝马1",
105                 "id": 21
106               },
107               {
108                 "name": "宝马2",
109                 "id": 22
110               }]
111             },
112             {
113               "letter": "k",
114               "list": [{
115                 "name": "宝马1",
116                 "id": 23
117               },
118               {
119                 "name": "宝马2",
120                 "id": 24
121               }]
122             },
123           ]

 html 结构：

主体部分

 1 <scroll-view class="content" scroll-y="true" :style="scrollheight" :scroll-top="scrolldata.scrolltop" :scroll-into-view="toview">
 2       <ul class="brandlist">
 3         <li v-for="(item, index) in list" :key="index" :id="item.letter">
 4           <h2>{{item.letter}}</h2>
 5           <div v-for="(el, i) in item.list" :key="i" class="pro" @click="gettoast(el.name)">
 6             <img src="/static/images/user.png" alt="" mode="aspectfit">
 7             <span>{{el.name}}</span>
 8           </div>
 9         </li>
10       </ul>
11     </scroll-view>

1 // 侧边导航栏
2 <div class="letterlist" @touchstart="handlertouchmove" 
3         @touchmove="handlertouchmove" 
4         @touchend="handlertouchend" :style="fixedtop">
5       <p v-for="(item, index) in list" :key="index" @click="getletter(item.letter)">{{item.letter}}</p>
6     </div>

 

 js初始数据：

scrolldata: {
        scrolltop: 0,
      },
      toview:'a',

step1： 

首先，侧边导航栏肯定是用fixed定位固定（一般在右侧），其次在竖直方向居中，调用wx.getsysteminfo 

 

1 let fixedtop = 0;
2       let length = this.list.length // 取到list数组的length，因为list的length决定了侧边导航的高度
3       wx.getsysteminfo({
4         success(res) {
5           fixedtop = (res.windowheight - (20 * length))/2  //20为侧边导航每个p的高度
6         }
7       })

 

step2

手指在侧边导航滑动时的js

 1 handlertouchmove (e) {
 2       let touches = e.touches[0] || {}
 3       let pagey = touches.pagey
 4       let rest = pagey - this.fixedtop
 5       let index = math.ceil(rest / 20)
 6       console.log(this.list.length, index, 206);
 7       console.log(index,195);
 8       if(index > this.list.length) {
 9         index = this.list.length - 1// 
10       }
11       if( 0 <index <= this.list.length) { // 1213  10  9
12         index = index - 1
13       }
14       if(index <= 0) {
15         index = 0
16       }
17       let letter = this.list[index].letter
18       wx.showtoast({
19         title: letter,
20         icon: 'none',
21         duration: 2000
22       })
23       this.toview = letter
24     },
25     handlertouchend () {
26       wx.hideloading()
27     },

 

step3

点击侧边索引时的js

1     getletter (letter) {
2       this.toview = letter
3     },

 

结束惹，88， 下次见

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