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Vue and ECharts4Taro3 Practical Guide: Create a data-driven mobile application from scratch
Introduction:
In mobile application development, the visual display of data is a very important part. As a popular front-end framework, Vue provides rich functions and a powerful ecosystem, and ECharts4Taro3 is a data visualization library based on Vue. This article will introduce how to use Vue and ECharts4Taro3 to build a data-driven mobile application from scratch.
npm install -g @tarojs/cli
Create a new project using Taro:
taro init myProject cd myProject
Install Taro’s related dependencies:
npm install
npm install echarts-for-taro3
Then, we need to configure the ECharts4Taro3 style file in Taro’s configuration file. Add the following content in the app.config.js
file:
export default { // ... usingComponents: { // ... "ec-canvas": "@/components/echarts/echarts" } // ... }
Next, create a folder named "echarts" under the src/components
directory , and create a file named "echarts.vue" in it. Introduce the ECharts4Taro3 library into this file and define an ECharts component, as shown below:
<template> <ec-canvas @init="onInit" canvas-id="mychart" :canvas-type="canvasType" :ec="ec" ></ec-canvas> </template> <script> import * as echarts from "echarts/core"; import { LineChart } from "echarts/charts"; import { CanvasRenderer } from "echarts/renderers"; echarts.use([LineChart, CanvasRenderer]); export default { props: ["data"], data() { return { ec: { lazyLoad: true }, canvasType: "2d" }; }, mounted() { this.$emit("init", this.initChart); }, methods: { initChart(canvas, width, height, dpr) { const chart = echarts.init(canvas, null, { width: width, height: height, devicePixelRatio: dpr }); this.setOptions(chart); return chart; }, setOptions(chart) { const option = { ... }; chart.setOption(option); } } }; </script>
In the above code, we first introduce the relevant modules of ECharts, and then define an ECharts component. In the mounted
method of the component, we pass the initialization function initChart
to the parent component through the emit
event. Calling this function in the parent component can initialize the chart and set Chart options.
<template> <view class="container"> <echarts :data="chartData" @init="onChartInit"></echarts> </view> </template> <script> import echarts from "@/components/echarts/echarts.vue"; export default { components: { echarts }, data() { return { chartData: [...] }; }, methods: { onChartInit(chart) { setTimeout(() => { // 更新图表数据 this.chartData = [...]; // 重新设置图表选项 chart.setOptions({ ... }); }, 1000); } } }; </script>
In the above code, we first imported the Vue component using the ECharts4Taro3 component. Then, the 92547b21ee79626461538acc7096ccf0
tag is used in the component's template, and the chart's data is passed to the ECharts component through the data
attribute. When the chart is initialized, we can obtain the chart instance chart
through the callback function triggered by the @init
event, and then update the chart data in the setTimeout
function and options.
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