<!--table组件需要使用ref="table"-->
<template>
 <div>
 <el-table :data="tableData" ref="table" stripe style="width: 100%" @selection-change="handleSelectionChange">
  <el-table-column type="selection" width="55"></el-table-column>
  <el-table-column prop="name" label="商品名称"></el-table-column>
  <el-table-column prop="barcode" label="商品编码"></el-table-column>
  <el-table-column prop="quantity" label="区域总库存"></el-table-column>
 </el-table>
 <div class="block" v-show="page.pageTotal>10">
  <el-pagination @current-change="handleCurrentChange" :current-page.sync="page.currentPage" :page-size="page.pnum" layout="total, prev, pager, next , jumper" :total="page.pageTotal">
  </el-pagination>
 </div>
 <div>
  {{multipleSelectionAll.length}}
 </div>
 </div>
</template>

export default {
 data(){
  return {
  tableData: [], // 表格数据 
  multipleSelectionAll:[],//所有选中的数据包含跨页数据
  multipleSelection:[],// 当前页选中的数据
  idKey: 'barcode', // 标识列表数据中每一行的唯一键的名称
  page:{
   //每页数据量
   pnum:10,
   //数据总数
   pageTotal:0,
   //当前页，从1开始
   currentPage:1,
  }
  }
 },
 methods: {
  handleCurrentChange(){
  this.changePageCoreRecordData();
  if(!this.$isNull(this.page.pageTotal)) this.getGoodsList();
  },
  handleSelectionChange (val) {
  this.multipleSelection = val;
  //实时记录选中的数据
  setTimeout(()=>{
   this.changePageCoreRecordData();
  }, 50)
  },
  setSelectRow() {
  if (!this.multipleSelectionAll || this.multipleSelectionAll.length <= 0) {
   return;
  }
  // 标识当前行的唯一键的名称
  let idKey = this.idKey;
  let selectAllIds = [];
  let that = this;
  this.multipleSelectionAll.forEach(row=>{
   selectAllIds.push(row[idKey]);
  })
  this.$refs.table.clearSelection();
  for(var i = 0; i < this.tableData.length; i++) {   
   if (selectAllIds.indexOf(this.tableData[i][idKey]) >= 0) {
   // 设置选中，记住table组件需要使用ref="table"
   this.$refs.table.toggleRowSelection(this.tableData[i], true);
   }
  }
  },
  // 记忆选择核心方法
  changePageCoreRecordData () {
  // 标识当前行的唯一键的名称
  let idKey = this.idKey;
  let that = this;
  // 如果总记忆中还没有选择的数据，那么就直接取当前页选中的数据，不需要后面一系列计算
  if (this.multipleSelectionAll.length <= 0) {
   this.multipleSelectionAll = this.multipleSelection;
   return;
  }
  // 总选择里面的key集合
  let selectAllIds = [];
  this.multipleSelectionAll.forEach(row=>{
   selectAllIds.push(row[idKey]);
  })
  let selectIds = []
  // 获取当前页选中的id
  this.multipleSelection.forEach(row=>{
   selectIds.push(row[idKey]);
   // 如果总选择里面不包含当前页选中的数据，那么就加入到总选择集合里
   if (selectAllIds.indexOf(row[idKey]) < 0) {
   that.multipleSelectionAll.push(row);
   }
  })
  let noSelectIds = [];
  // 得到当前页没有选中的id
  this.tableData.forEach(row=>{
   if (selectIds.indexOf(row[idKey]) < 0) {
   noSelectIds.push(row[idKey]);
   }
  })
  noSelectIds.forEach(id=>{
   if (selectAllIds.indexOf(id) >= 0) {
   for(let i = 0; i< that.multipleSelectionAll.length; i ++) {
    if (that.multipleSelectionAll[i][idKey] == id) {
    // 如果总选择中有未被选中的，那么就删除这条
    that.multipleSelectionAll.splice(i, 1);
    break;
    }
   }
   }
  })
  },
  //请求接口部分
  getGoodsList(){
  let data = {};
  data['page'] = this.page.currentPage;
  data['pnum'] = this.page.pnum;
  this.$ajax({
   url:'goods/list',
   data:data
  }).then(val => {
   this.tableData = val.data.rows ? val.data.rows : [];
   this.page = {
   pnum:10,
   pageTotal:val.data.total,
   currentPage:val.data.page,
   };
   setTimeout(()=>{
   this.setSelectRow();
   }, 50)
  })
  }
 },
 created () {
  this.getGoodsList()
 }
 }