Vue and ECharts4Taro3 Practical Guide: Build a data-driven mobile application from scratch

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.

1. Preparation
   First, we need to install and configure the relevant development environment. Make sure you have Node.js and the npm package manager installed. Next, install the Taro scaffolding tool through the following command:

npm install -g @tarojs/cli

Create a new project using Taro:

taro init myProject
cd myProject

Install Taro’s related dependencies:

npm install

2. Integrate ECharts4Taro3
   Next, we need to integrate ECharts4Taro3. First, install the ECharts4Taro3 core library through the following command:

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.

3. Using ECharts4Taro3 component
   In practical applications, we can use ECharts4Taro3 component in any Vue component. Here is a simple example:

<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 <echarts> 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.

4. Conclusion
   Through the practical guide of this article, we learned how to use Vue and ECharts4Taro3 to build a data-driven mobile application. From preparation to integrating the ECharts4Taro3 library and using ECharts components, we learned the entire process step by step and practiced it with code examples. I hope this article is helpful to everyone, and happy coding!

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