小程序分页实践之编写可复用分页组件

├── components
│    ├── meeting-item   # 列表item
│    └── pagination      # 分页组件
├── model
│  └── user.js          # 我的相关 model
└── pages
│    └── user            # 我的相关页面
│    ├── meetings    # 我的会议（就是tab要分页的页面啦）
│    └── ...
│
└── vant-weapp

// components/pagination/index.js
Component({
 properties: {
  key: {
   type: String,
   observer: '_loadMoreData' // _loadMoreData 为分页操作
  }
 }
})

<!-- pages/user/meetings/index.wxml -->
<tabs active="{{currentTab}}" bind:change="onChange">
  <tab title="我的会议" data-key="{{type['JOIN']}}">
   <view class="meeting-list">
     <pagination 
      name="JOIN"
      key="{{joinKey}}" 
     >
     </pagination>
   </view>
  </tab>

  <tab title="我的预约">
   <view class="meeting-list">
    <pagination 
     name="BOOK"
     key="{{bookKey}}"
    >
    </pagination>
   </view>
  </tab>
</tabs>

Page({
 onReachBottom(){
  const key = scene[+this.data.currentTab].key // 对应tab对应key
  this.setData({
   [key]: random(16)
  })
 }
})

// components/pagination/index.js
Component({
 properties: {
  name: String,
  key: {
   type: String,
   observer: '_loadMoreData' // _loadMoreData 为分页操作
  },
  size: { // 每次加载条目数
   type: Number,
   value: 10
  },
  total: Number, // 页面总数
  list: {         // 已加载条目
   type: Array,
   observer: '_endState'   // 每次加载完新数据，判断数据是否全部加载完成
  }
 },

 data: {
  page: 0,        // 当前第几页
  loading: false, // 是否正在加载
  ended: false  // 数据是否已全部加载完成
 },
 
 methods: {
  _loadMoreData(){
   const { loading, ended, size } = this.data
   if (loading) return // 上一页还未加载完成，不加载
   if (ended) return  // 当前页面全部加载完，不加载
   const page = this.data.page + 1

   this.setData({
    loading: true, // 开始加载新页面loading设置为true
    page
   })
   // 触发加载下一页，并传入参数
   this.triggerEvent('getList', {
    page,
    size
   })
  },
  _endState(val, oldVal) {
   const { total, list } = this.properties
   let ended = false
   // 判断数据是否全部加载完成
   if (list.length >= total) {
    ended = true
   }
   this.setData({
    loading: false, // 当前页面加载完成，loading设置为false
    ended
   })
  }
 }
})

<!-- pages/user/meetings/index.wxml -->
<pagination 
 name="BOOK"
 key="{{bookKey}}"
 bind:getList="getBookMeetings"
 list="{{bookMeetings}}"
 total="{{bookTotal}}"
>
</pagination>

<view wx:for="{{list}}" wx:for-item="item" wx:key="index">
 <slot></slot>
</view>

// components/pagination/index.json
{
 "componentGenerics": {
  "selectable": true
 },
 // ...
}

<!-- components/pagination/index.wxml -->
<view wx:for="{{list}}" wx:for-item="item" wx:key="index">
  <selectable item="{{item}}"></selectable>
</view>

<!-- pages/user/meetings/index.wxml -->
<pagination 
 generic:selectable="meeting-item"
  // ... 其他属性
>
</pagination>

// pages/user/meetings/index.json
{
 "usingComponents": {
  "pagination":"/components/pagination/index",
  "meeting-item":"/components/meeting-item/index"
 }
}

// components/pagination/index.js
Component({
 properties: {
  initImmediately: {
   type: Boolean,
   value: true,
   observer: function(val){
    if (val && !this.data.initState) {
     this.initData()
    }
   }
  },
  // ...
 },
 data: {
   initState: false, // 是否已经加载过
   // ...
 },
 lifetimes: {
  attached: function () {
   if (this.data.initImmediately){
    this.initData()
   }
  },
 },
 methods: {
  initData(){
   console.info(`${this.data.name}:start init data`)
   this._loadMoreData()
   this.setData({
    initState: true
   })  
   },
  // ... 
   _endState(val, oldVal) {
   if (!this.data.initState) return 
   // ...
   },
 }
})

<!-- pages/user/meetings/index.wxml -->
<pagination 
  name="JOIN"
  init-immediately="{{currentTab==type['JOIN']}}"
  // ...
>
</pagination>

<pagination 
  name="BOOK"
  init-immediately="{{currentTab==type['BOOK']}}"
  // ...
>
</pagination>

<pagination 
 name="USER"
 key="{{key}}" 
 bind:getList="getUserList" 
 list="{{userList}}" 
 total="{{userTotal}}"
 generic:selectable="user-item"
>
</pagination>