Salesforce LWC学习(三十三) lightning-datatable 翻页bug处理
zero.zhang 人气:0本来lightning-datatable这种标签,基本上任何的项目都会用到而且很精通,所以当时感觉没有太大的单独一篇写的必要,在Salesforce LWC学习(三十) lwc superbadge项目实现 中也有使用这个标签的demo,所以有类似需要的小伙伴参考一下也可以照猫画虎搞定需求。项目中遇见了两个datatable的问题,解决以后感觉有必要写一下,后期遇见这种坑的小伙伴可以快速对应。话不多说,先弄一个简单的分页效果的UI,UI很丑,旨在实现功能。
AccountListController.cls:一个简单的搜索list返回
public without sharing class AccountListController { public static final Integer DEFAULT_PAGE_SIZE = 100; @AuraEnabled(cacheable=false) public static List<Account> fetchAccountList(String serializedAccount){ Account account = (Account)JSON.deserialize(serializedAccount,Account.class); String fetchAccountSQL = 'SELECT Id,Name,Industry,AccountSource,Owner.Name FROM Account WHERE IsDeleted = false '; if(String.isNotBlank(account.name)) { fetchAccountSQL += 'AND Name like' + '\'%' + account.name + '%\''; } if(String.isNotBlank(account.industry)) { fetchAccountSQL += ' AND industry = \'' + account.industry + '\''; } if(String.isNotBlank(account.AccountSource)) { fetchAccountSQL += ' AND AccountSource = \'' + account.AccountSource + '\''; } Integer accountSize = DEFAULT_PAGE_SIZE; fetchAccountSQL += ' LIMIT ' + accountSize; List<Account> accountList = Database.query(fetchAccountSQL); return accountList; } }
accountSearchForm.html
<template> <!--use LDS to bind account --> <lightning-record-edit-form object-api-name='Account' onsubmit={handleRecordFormSubmit} > <!--used to show section close/open--> <lightning-accordion allow-multiple-sections-open active-section-name={activeSections}> <lightning-accordion-section name="basic" label="basic"> <lightning-layout multiple-rows="true"> <lightning-layout-item padding="around-small" flexibility='auto' size='4'> <lightning-input-field field-name='Name'></lightning-input-field> </lightning-layout-item> <lightning-layout-item padding="around-small" flexibility='auto' size='4'> <lightning-input-field field-name="AccountSource"></lightning-input-field> </lightning-layout-item> <lightning-layout-item padding="around-small" flexibility='auto' size='4'> <lightning-input-field field-name="Industry"></lightning-input-field> </lightning-layout-item> </lightning-layout> </lightning-accordion-section> </lightning-accordion> <!-- button group area --> <lightning-layout horizontal-align="center"> <lightning-layout-item > <lightning-button variant="brand" label="search" type="submit" name="search"></lightning-button> </lightning-layout-item> </lightning-layout> </lightning-record-edit-form> </template>
accountSearchForm.js
import { LightningElement,track } from 'lwc'; export default class AccountSearchForm extends LightningElement { @track activeSections = ['basic']; @track account; handleRecordFormSubmit(event) { event.preventDefault(); this.account = event.detail; this.dispatchEvent(new CustomEvent('searchaccount',{detail:this.account})); } }
myAccountList.html
<template> <lightning-card title="list for account data" icon-name="standard:account"> <div style="height: 150px;"> <lightning-datatable data={accountListForCurrentPage} columns={columns} show-row-number-column key-field="id"> </lightning-datatable> </div> <lightning-layout horizontal-align="center"> <lightning-layout-item flexibility='auto' size='1'> <lightning-combobox value={perSize} options={entryList} placeholder="choose size" onchange={handlePerSizeChange} > </lightning-combobox> </lightning-layout-item> <lightning-layout-item flexibility='auto' size='9' class="slds-text-align_center"> totalSize: {totalSize} </lightning-layout-item> <lightning-layout-item flexibility="auto" size="2"> <lightning-button variant="brand" label="<--" disabled={isFirstPage} onclick={handlePreviousPageClick}></lightning-button> <lightning-button variant="brand" label="-->" disabled={isLastPage} title="next" onclick={handleNextPageClick}></lightning-button> </lightning-layout-item> </lightning-layout> </lightning-card> </template>
myAccountList.js
import { LightningElement,api, track } from 'lwc'; const columns = [ {label: 'Account Name', fieldName: 'Name'}, {label: 'Account Industry', fieldName: 'Industry'}, {label: 'Account Source', fieldName: 'AccountSource'}, {label: 'Owner Name', fieldName: 'OwnerName'} ]; export default class MyAccountList extends LightningElement { //searched account list used to show in component table @api accountList; //indicator if table header checkbox check or not, true for check @api totalChecked; //list total entryList @api totalSize; //per size for show in table @api perSize; //current page index @api currentPageIndex; //list show in table @api accountListForCurrentPage; //indicator if current page is first page @api isFirstPage; //indicator if current page is last page @api isLastPage; @track columns = columns; get entryList() { return [ { label: '3', value: '3' }, { label: '5', value: '5' }, { label: '10', value: '10' }, ]; } /** * description: item checkbox check/uncheck, dispatch itemcheck custom event and parent component handle this * @param event system event,used to get which item check/uncheck */ handleItemCheckboxClick(event) { this.dispatchEvent(new CustomEvent('itemcheck',{detail:{id:event.currentTarget.value,checked:event.currentTarget.checked}})); } /** * description: table header checkbox check/check, dispatch allcheck custom event * @param event system event, used to get if table header checkbox check/uncheck */ handleAllCheckboxClick(event) { this.dispatchEvent(new CustomEvent('allcheck',{detail:{checked:event.currentTarget.checked}})); } handleNextPageClick() { this.dispatchEvent(new CustomEvent('nextpage')); } handlePreviousPageClick() { this.dispatchEvent(new CustomEvent('previouspage')); } handlePerSizeChange(event) { let currentSize = event.detail.value; this.dispatchEvent(new CustomEvent('persizechange',{detail:{currentSize:currentSize}})); } }
accountListContainer.html
<template> <c-account-search-form onsearchaccount={handleSearchAccountEvent}></c-account-search-form> <c-my-account-list is-first-page={isFirstPage} is-last-page={isLastPage} account-list={accountList} account-list-for-current-page={accountListForCurrentPage} total-checked={totalChecked} onitemcheck={handleItemCheckEvent} onallcheck={handleAllCheckedEvent} onnextpage={handleNextPageEvent} onpreviouspage={handlePreviousPageEvent} total-size={totalSize} per-size={perSize} onpersizechange={handlePerSizeChangeEvent}></c-my-account-list> </template>
accountListContainer.js
import { LightningElement,track } from 'lwc'; import fetchAccountList from '@salesforce/apex/AccountListController.fetchAccountList'; export default class AccountListContainer extends LightningElement { //account list used to show in account table @track accountList = []; //account form used to store form information user searched @track accountForm; //errors when fetch account list error @track errors; //indicator if table header total check box checked or not, true means checked @track totalChecked = false; //indicator if list modal close @track showSelectedListModal = false; @track data = []; //list total size @track totalSize; //per size for show in table @track perSize = 5; //current page index @track currentPageIndex; //list show in table @track accountListForCurrentPage; @track isFirstPage = true; @track isLastPage = true; /** * description: search account data by form information and set the result to account list to show in table * @param event system event used to get form detail information */ handleSearchAccountEvent(event) { this.totalChecked = false; this.accountForm = event.detail; fetchAccountList({serializedAccount:JSON.stringify(event.detail)}) .then(result => { this.accountList = result; this.totalSize = result.length; this.currentPageIndex = 1; if(this.totalSize > this.perSize * this.currentPageIndex) { this.setPagination(); } else { this.accountListForCurrentPage = this.accountList; this.accountListForCurrentPage.forEach(item => { if(item.Owner) { item.OwnerName = item.Owner.Name; } }); this.isLastPage = true; } this.errors = undefined; }) .catch(error =>{ this.errors = error; this.accountList = undefined; }); } handlePreviousPageEvent() { this.currentPageIndex = this.currentPageIndex - 1; this.setPagination(); } handlePerSizeChangeEvent(event) { this.perSize = event.detail.currentSize; this.currentPageIndex = 1; this.setPagination(); } handleNextPageEvent() { this.currentPageIndex = this.currentPageIndex + 1; this.setPagination(); } setPagination() { this.accountListForCurrentPage = []; let tmpList = []; for(let index = (this.perSize * (this.currentPageIndex - 1)); index < this.totalSize; index++) { if(index < this.perSize * this.currentPageIndex) { if(this.accountList[index].Owner) { this.accountList[index].OwnerName = this.accountList[index].Owner.Name; } tmpList.push(this.accountList[index]); } } this.accountListForCurrentPage = tmpList; if(this.currentPageIndex === 1) { this.isFirstPage = true; } else { this.isFirstPage = false; } if(this.perSize * this.currentPageIndex >= this.totalSize) { this.isLastPage = true; } else { this.isLastPage = false; } } }
结果展示:
看上去还可以是吧,但是有两个潜在的问题。
按照以下操作步骤,第一页有拖动条,选择了第5条数据
点击翻页以后,两个问题如下:
1)第二页的第五条同样的默认勾选了,尽管这个时候我们如果使用event.detail.selectedRows去获取选中的选项,第二页是没有在这里的,但是UI撒谎了,这个是一个很严重的bug;
2)第二页进去以后,滚动条没有在最上面,即没有默认展示第一条数据。
这两个问题,第二个问题是小问题,可以忍;第一个问题会让用户有concern,属于很严重的问题。但是什么原因呢???其实我也不太清楚是什么原因,datatable官方的设计中也没有翻页的demo,大部分都是loadMore当页增加数据场景,所以可能针对每页的index处选中效果有某个隐藏的bug。当我们尽管更新了list的数据,但是index给渲染了,很容易是render层的bug。所以我们想一下如何去处理这种问题。既然同步的渲染有问题,我们考虑其他方式,setTimeout弄成异步调用或者改成Promise实现。优化后的方案如下所示:
myAccountList.js新增一个方法
@api handleTableScrollTop() { this.template.querySelector('div').scrollTop = 0; }
accountListContainer.js修改一下 setPagination方法。新增了 setList这个Promise,js执行顺序 : 同步代码 > Promise > setTimeout这种异步方式。
setPagination() { this.accountListForCurrentPage = []; let tmpList = []; for(let index = (this.perSize * (this.currentPageIndex - 1)); index < this.totalSize; index++) { if(index < this.perSize * this.currentPageIndex) { if(this.accountList[index].Owner) { this.accountList[index].OwnerName = this.accountList[index].Owner.Name; } tmpList.push(this.accountList[index]); } } //this.accountListForCurrentPage = tmpList; if(this.currentPageIndex === 1) { this.isFirstPage = true; } else { this.isFirstPage = false; } if(this.perSize * this.currentPageIndex >= this.totalSize) { this.isLastPage = true; } else { this.isLastPage = false; } const setList = () => new Promise((resolve, reject) => { resolve(tmpList); }); setList() .then((result) => { this.accountListForCurrentPage = tmpList; this.template.querySelector('c-my-account-list').handleTableScrollTop(); }); }
通过以上的代码就可以解决上述的两个问题了。原理的话因为不清楚 datatable的渲染方式,只能找到解决这种问题的workaround的方式,同时作为sf开发人员在开发lightning的过程中,javascript真的是越来越重要了!!!
总结:篇中代码实现了通过 lightning-datatable翻页效果以及针对两个潜在的bug的修复。偏中有错误欢迎指出,有不懂欢迎留言。有更好方式欢迎交流。
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