1、遞歸組件-簡單樹形控件預覽及問題
在編寫樹形組件時遇到的問題：
2、樹形控件基本結構及樣式
<template> <ul class="vue-tree"> <li class="tree-item"> <div class="tree-content"><!--節點內容--> <div class="expand-arrow"></div><!--展開或收縮節點按鈕--> <div class="tree-label">小學</div><!--節點文本內容--> </div> <ul class="sub-tree"><!--子節點--> <li class="tree-item expand"> <div class="tree-content"> <div class="expand-arrow"></div> <div class="tree-label">語文</div> </div> </li> <li class="tree-item"> <div class="tree-content"> <div class="expand-arrow"></div> <div class="tree-label">數學</div> </div> </li> </ul> </li> </ul></template><style lang="stylus">.vue-tree{ list-style: none; padding: 0; margin: 0; .tree-item{ cursor: pointer; transition: background-color .2s; .tree-content{ position: relative; padding-left: 28px; &:hover{ background-color: #f0f7ff; } } .expand-arrow{ position: absolute; top: 0; left: 0; width: 28px; height: 28px; cursor: pointer; &::after{ position: absolute; top: 50%; left: 50%; display: block; content: ' '; border-width: 5px; border-style: solid; border-color: transparent; border-left-color: #ccc; margin: -5px 0 0 -2.5px; transition: all .2s; } } &.expand{ &>.tree-content{ background-color: #f0f7ff; &>.expand-arrow{ &::after{ transform: rotate(90deg); margin: -2.5px 0 0 -5px; } } } } .tree-label{ height: 28px; line-height: 28px; font-size: 14px; } .sub-tree{ display: none; list-style: none; padding: 0 0 0 28px; margin: 0; } &.expand>.sub-tree{ display: block; } &.no-child{ &>.tree-content{ &>.expand-arrow{ display: none; } } } }}</style>3、組件目錄及數據結構
目錄結構
vue-tree
VueTree.vue
TreeItem.vue
樹形控件數據結構
let treeData = [ { text: "一級", // 顯示的文字 expand: false, // 默認是否展開 children: [ // 子節點 { text: "一級-1", expand: false, }, { text: "一級-2", expand: false, children: [ { text: "一級-2-1", expand: false, }, { text: "一級-2-2", expand: false, } ] } ] }];3.1、 TreeItem.vue 代碼
<template> <li class="tree-item" :class="{expand: isExpand, 'no-child': !treeItemData.children || treeItemData.children.length === 0}"> <div class="tree-content" @click="_clickEvent"> <div class="expand-arrow" @click.stop="expandTree()"></div> <div class="tree-label">{{treeItemData.text}}</div> </div> <ul class="sub-tree" v-if="treeItemData.children && treeItemData.children.length > 0"> <!--TreeItem組件中調用TreeItem組件--> <TreeItem v-for="item in treeItemData.children" :tree-item-data="item" :key="uuid()" :tree-click-event="treeClickEvent"></TreeItem> </ul> </li></template><script> export default { name: "TreeItem", props: { treeItemData: { type: Object, default(){ return {}; } }, // 節點點擊事件 treeClickEvent: { type: Function, default() { return function () {}; } } }, data(){ return { // 節點是否展開 isExpand: this.treeItemData.expand || false } }, methods: { // 展開/收縮 expandTree(flag){ if(!this.treeItemData.children || this.treeItemData.children.length === 0){ return; } if(typeof flag === 'undefined'){ flag = !this.isExpand; }else{ flag = !!flag; } this.isExpand = flag; }, // 創建一個唯一id uuid(){ let str = Math.random().toString(32); str = str.substr(2); return str; }, // 節點點擊事件 _clickEvent(){ // 如果有傳遞事件函數，則調用事件函數并傳遞當前節點數據及組件 if(this.treeClickEvent && typeof this.treeClickEvent === 'function'){ this.treeClickEvent(this.treeItemData, this); } } } }</script>3.1.1、解決 組件如何才能遞歸調用？ 問題
在組件模板內調用自身 必須明確定義組件的name屬性 ，并且遞歸調用時組件名稱就是name屬性。如在 TreeItem.vue 組件中組件的name名稱為'TreeItem'，那么在template中調用時組件名稱就必須是 <TreeItem> 。
當然也可以全局注冊組件，具體可以查看vue官方文檔 遞歸組件
3.1.2、解決 遞歸組件點擊事件如何傳遞？ 問題
我這里的解決方案是使用 props 將事件函數傳遞進來，在點擊節點的時候調用事件函數，并把相應的數據傳遞進去。
之前也嘗試過使用 $emit 的形式并把數據傳遞過去，由于是遞歸組件，這樣一直 $emit ，到最外層時傳遞的數據就變了，比如傳遞是第3層節點的數據，到最后執行時數據就變成第1層節點的數據了
4、 VueTree.vue 組件
<template> <ul class="vue-tree"> <TreeItem v-for="(item, index) in treeData" :key="index" :treeItemData="item" :tree-click-event="treeClickEvent"></TreeItem> </ul></template><script> import TreeItem from "./TreeItem"; export default { name: "VueTreeMenu", components: { TreeItem }, props: { // 樹形控件數據 treeData: { type: Array, default(){ return []; } }, // 節點點擊事件 treeClickEvent: { type: Function, default() { return function () {}; } } } }</script><style lang="stylus">.vue-tree{ list-style: none; padding: 0; margin: 0; .tree-item{ cursor: pointer; transition: background-color .2s; .tree-content{ position: relative; padding-left: 28px; &:hover{ background-color: #f0f7ff; } } .expand-arrow{ position: absolute; top: 0; left: 0; width: 28px; height: 28px; cursor: pointer; &::after{ position: absolute; top: 50%; left: 50%; display: block; content: ' '; border-width: 5px; border-style: solid; border-color: transparent; border-left-color: #ccc; margin: -5px 0 0 -2.5px; transition: all .2s; } } &.expand{ &>.tree-content{ background-color: #f0f7ff; &>.expand-arrow{ &::after{ transform: rotate(90deg); margin: -2.5px 0 0 -5px; } } } } .tree-label{ height: 28px; line-height: 28px; font-size: 14px; } .sub-tree{ display: none; list-style: none; padding: 0 0 0 28px; margin: 0; } &.expand>.sub-tree{ display: block; } &.no-child{ &>.tree-content{ /*padding-left: 0;*/ &>.expand-arrow{ display: none; } } } }}</style>5、使用樹形組件
<template> <div class="app" id="app"> <VueTree :tree-data="treeData2" :tree-click-event="treeClickEvent"></VueTree> </div></template><script>import VueTree from "./components/vue-tree/VueTree";export default { name: 'app', data(){ return { treeData2: [ { text: "一級", // 顯示的文字 expand: false, // 默認是否展開 children: [ { text: "二級-1", expand: false, }, { text: "二級-2", expand: false, children: [ { text: "三級-1", expand: false, }, { text: "三級-2", expand: false, children: [ { text: "四級-1", expand: false, } ] } ] } ] }, { text: "一級-2", expand: false } ] } }, methods: { treeClickEvent(item, treeItem){ console.log(item); } }, components: { VueTree }}</script>總結
以上所述是小編給大家介紹的vue遞歸組件實戰之簡單樹形控件實例代碼,希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對武林網網站的支持！
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