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项目背景
103项目CPC卡使用模块在原有的表格展示数据的基础之上，增加环状饼图图表展示，采用tab切换的方式实现
问题描述
图表无法设置宽高，导致饼图无法渲染
具体代码
// 入口页<el-tabs type="card" class="cts_flex_tabs height-calc"><el-tab-pane label="CPC卡使用情况"><CtsTable :table-id="tableId":version="version"ref="cpcCtsTable"class="cpc-use-table":spanMethod="spanMethod":loading="loading":table-data="tableData":add-row-class-name="addRowClassName":columns="columns" /></el-tab-pane><el-tab-pane label="CPC卡库存情况分析"><cpc-inventory ref="cpcInventoryRef" /></el-tab-pane>
</el-tabs>// cpc-inventory组件<div class="cpc-inventory" ref="inventoryRef"><div class="pie-chart" ref="pieChart"></div>
</div><style lang="less" scoped>
.cpc-inventory {height: 100%;width: 100%;.pie-chart {height: 100%;width: 100%;}
}
</style>
页面在初始化时会同时加载两个tab，但是CPC卡库存情况分析图表tab中的元素具体的宽高值是无法获取到的（display: none隐藏了），如下图：
在onMounted钩子函数中无论是否使用nextTick，打印出的inventoryRef的offsetHeight都是0，尽管设置了元素的宽高均为100%，但是由于元素没有渲染出来，导致无法获取实际高度，而是高度为0。原本是想通过获取到父元素inventoryRef的具体宽高值，然后设置图表容器pieChart的宽高从而实现图表的正常渲染。
注意：页面初始化时，CPC卡库存情况分析图表组件中的onMounted会执行，但此时无法获取父元素宽高。
解决方案
采用ResizeObserver
ResizeObserver 是浏览器提供的一个 API，用于监听 DOM 元素尺寸的变化（如宽度、高度、边框、内边距等）。它比传统的 window.resize 或 MutationObserver 更高效，专门用于监测元素的尺寸变化。
代码实现
<div class="cpc-inventory" ref="inventoryRef"><div class="pie-chart" ref="pieChart"></div>
</div>const setupResizeObserver = () => {if (!inventoryRef.value) return;if (resizeObserver.value) {resizeObserver.value.disconnect();}resizeObserver.value = new ResizeObserver((entries) => {for (const entry of entries) {const { height } = entry.contentRect;if (height > 0 && !chart) {initPieChart();}}});resizeObserver.value.observe(inventoryRef.value);
};
onMounted(() => {setupResizeObserver();
});
onBeforeUnmount(() => {if (resizeObserver.value) {resizeObserver.value.disconnect();}
});
代码解释：
在页面初始化时，钩子函数onMounted中调用setupResizeObserver函数，通过resizeObserver.value.observe(inventoryRef.value)监听inventoryRef元素，当切换tab到CPC卡库存情况分析图表展示组件时，此时能够监测到inventoryRef元素有了宽高值，那么由于设置了宽高为100%，因此子元素pieChart也就有了宽高，就可以进行图表的渲染，至此也就解决了上述的问题。
问题回顾
上面的是解决方案中的一种，还有另外一种方案：为两个tab添加name属性，在图表组件中添加v-if判断，代码如下：
<el-tabs type="card" class="cts_flex_tabs height-calc" v-model="activeTab" @click="..."><el-tab-pane label="CPC卡使用情况" name="use"><CtsTable :table-id="tableId":version="version"ref="cpcCtsTable"class="cpc-use-table":spanMethod="spanMethod":loading="loading":table-data="tableData":add-row-class-name="addRowClassName":columns="columns" /></el-tab-pane><el-tab-pane label="CPC卡库存情况分析" name="inventory"><cpc-inventory ref="cpcInventoryRef" v-if="activeTab == 'inventory'" /></el-tab-pane>
</el-tabs>
这种方案是通过v-if判断，使得cpc-inventory组件的钩子函数onMounted在页面初始化加载时不会执行，只有切换到此tab时才会执行。然后我们可以在nextTick中进行图表初始化渲染。此方案的劣势是用户从表格切换到图表时，每次都要执行图表的初始化过程。方案1只有初次加载图表时才会进行初始化过程，后续切换只是完成数据更新，用户无法看到图标初始化过程。
注意
Node.js 或特殊环境不支持或者无法识别**ResizeObserver**，会有报错信息：Cannot find name 'ResizeObserver'. Did you mean 'resizeObserver'?
解决方案：
-
确保
tsconfig.json包含 DOM 类型（推荐）{"compilerOptions": {"lib": ["dom", "es6"] // 确保包含 "dom"} } -
有时方案1没生效，则需要安装
@types/resize-observer-browser（适用于某些特殊环境）npm install --save-dev @types/resize-observer-browser # 或 yarn add --dev @types/resize-observer-browser在页面中引入
<script> .... import ResizeObserver from "resize-observer-polyfill"; ....</script>
适用场景
表格展示与图表展示通过tab组件切换（或者通过v-show），而不是通过v-if的方式动态设置显示与隐藏
完整代码分享
// 父组件<el-tabs type="card" class="cts_flex_tabs height-calc"><el-tab-pane label="CPC卡使用情况"><CtsTable :table-id="tableId":version="version"ref="cpcCtsTable"class="cpc-use-table":spanMethod="spanMethod":loading="loading":table-data="tableData":add-row-class-name="addRowClassName":columns="columns" /></el-tab-pane><el-tab-pane label="CPC卡库存情况分析"><cpc-inventory ref="cpcInventoryRef" /></el-tab-pane>
</el-tabs>...
// 查询获取列表数据
listRefresh(pageIndex = 1) {this.loading = truelet params = {...api.getCpcUseInfoReportList,data: {...this.searchForm,startHour: parseInt(this.searchForm.startHour.split(':')[0], 10),endHour: parseInt(this.searchForm.endHour.split(':')[0], 10),},}request(params).then((data) => {this.loading = falsethis.isBtnLoader = falsethis.tableData = data.datathis.$refs.cpcInventoryRef.updateData(this.tableData, this.searchForm.cityCode);}).catch((error) => {this.loading = falsethis.isBtnLoader = falsethis.$message.error(error.message)})
},
// 图表组件<template><div class="cpc-inventory" ref="inventoryRef"><div class="pie-chart" ref="pieChart"></div></div>
</template><script lang='ts'>
import useCommon from "@/hooks/use-common";
import {ref,reactive,defineComponent,onMounted,computed,toRefs,watch,onBeforeUnmount,
} from "@vue/composition-api";
import useResizeSearch from "@/hooks/use-resizeSearch";
import api from "@/api";
import request from "@/axios/fetch";
import * as echarts from "echarts";
import ResizeObserver from "resize-observer-polyfill";export default defineComponent({name: "CpcInventory",components: {},props: {},setup(props, { emit }) {const { proxy } = useCommon(); // 作为this使用const { isXLCol } = useResizeSearch();const pieChart = ref(null);let chart = null;const inventoryRef = ref(null);const resizeObserver = ref(null);const chartData = ref([]); // 饼图数据const centerShowInfo = reactive({name: "浙江省中心",kc: 0,pb: 0,});const setCenterShwoInfo = ({ city, inventory, matching }) => {centerShowInfo.name = city;centerShowInfo.kc = inventory;centerShowInfo.pb = matching;};const initPieChart = () => {if (pieChart.value) {chart = echarts.init(pieChart.value);const option = {tooltip: {trigger: "item",renderMode: "html", // 启用 HTML 模式formatter: ({ data }) => {return `<div style="font-size: 14px;"><p style="font-weight: bold; margin: 0 0 5px 0;">${data.name}</p><p style="margin: 2px 0;">库存: ${data.value}</p><p style="margin: 2px 0;">配比: ${data.pb}</p><p style="margin: 2px 0;">建议调入量: ${data.jytrl}</p></div>`;},// 定义富文本样式rich: {name: {fontSize: 16,fontWeight: "bold",color: "#333",padding: [0, 0, 5, 0],},value: {color: "#666",fontSize: 14,},ratio: {color: "#ff9900",fontSize: 14,},suggest: {color: "#ff0000",fontSize: 14,fontWeight: "bold",},},},legend: {orient: "vertical",bottom: "bottom",},series: [{name: "",type: "pie",radius: ["30%", "40%"],data: chartData.value,padAngle: 0,// value 字段是必需的，用于确定扇形区域的大小。// 可以通过 formatter 自定义标签内容，展示其他字段。label: {show: true,position: "outside", // 标签显示在外部formatter: function ({ data }) {if (data.jytrl > 0) {return `{name|${data.name}}\n{value|库存: ${data.value}} {ratio|配比: ${data.pb}} {desc|建议调入量: ${data.jytrl}}`;} else if (data.jytrl < 0) {return `{negativeName|${data.name}}\n{negativeValue|库存: ${data.value}} {negativeRatio|配比: ${data.pb}} {negativeDesc|建议调入量: ${data.jytrl}}`;}return `{zeroName|${data.name}}\n{zeroValue|库存: ${data.value}} {zeroRatio|配比: ${data.pb}} {zeroDesc|建议调入量: ${data.jytrl}}`;},rich: {name: {fontSize: 14,fontWeight: "bold",lineHeight: 24,color: "#F56C6C",},value: {fontSize: 12,color: "#F56C6C",lineHeight: 20,},ratio: {fontSize: 12,color: "#F56C6C",lineHeight: 20,},desc: {fontSize: 12,color: "#F56C6C",lineHeight: 20,},negativeName: {fontSize: 14,fontWeight: "bold",lineHeight: 24,color: "#67C23A",},negativeValue: {fontSize: 12,color: "#67C23A",lineHeight: 20,},negativeRatio: {fontSize: 12,color: "#67C23A",lineHeight: 20,},negativeDesc: {fontSize: 12,color: "#67C23A",lineHeight: 20,},zeroName: {fontSize: 14,fontWeight: "bold",lineHeight: 24,color: "#333",},zeroValue: {fontSize: 12,color: "#333",lineHeight: 20,},zeroRatio: {fontSize: 12,color: "#333",lineHeight: 20,},zeroDesc: {fontSize: 12,color: "#333",lineHeight: 20,},},},labelLine: {show: true, // 显示引导线},emphasis: {itemStyle: {shadowBlur: 10,shadowOffsetX: 0,shadowColor: "rgba(0, 0, 0, 0.5)",},},},],graphic: {type: "text",left: "center",top: "center",style: {text: [`{title|${centerShowInfo.name}}`,`{value|库存: ${centerShowInfo.kc}}`,`{desc|配比: ${centerShowInfo.pb}}`,].join("\n"), // 用 \n 换行rich: {// 定义每一行的样式title: {fontSize: 24,fontWeight: "bold",color: "#333",lineHeight: 36,textAlign: "center",},value: {fontSize: 16,color: "#333",lineHeight: 30,textAlign: "center",},desc: {fontSize: 16,color: "#333",lineHeight: 30,textAlign: "center",},},},},};chart.setOption(option);}};const updateData = (val, isSingleCity) => {if (val.length) {chartData.value = val.filter((ele) => ele.city).map((item) => ({value: item.inventory,name: item.city,pb: item.matching,jytrl: item.suggest,}));if (isSingleCity) {// 单区域const totalInfo = val.find((ele) => ele.area == "合计");setCenterShwoInfo(totalInfo);} else {// 全域const totalInfo = val.find((ele) => ele.area == "总计");setCenterShwoInfo({ ...totalInfo, city: "浙江省中心" });}} else {chartData.value = [];setCenterShwoInfo({ city: "", inventory: 0, matching: 0 });}if (chart) {chart.clear();initPieChart();}};const setupResizeObserver = () => {if (!inventoryRef.value) return;if (resizeObserver.value) {resizeObserver.value.disconnect();}resizeObserver.value = new ResizeObserver((entries) => {for (const entry of entries) {const { height } = entry.contentRect;if (height > 0 && !chart) {initPieChart();}}});resizeObserver.value.observe(inventoryRef.value);};onMounted(() => {setupResizeObserver();});onBeforeUnmount(() => {if (resizeObserver.value) {resizeObserver.value.disconnect();}if (chart) {chart.dispose();chart = null;}});return {pieChart,inventoryRef,updateData,};},
});
</script><style lang="less" scoped>
.cpc-inventory {height: 100%;width: 100%;.pie-chart {height: 100%;width: 100%;}
}
</style>