去官网下载整个项目：

https://github.com/ecomfe/echarts-for-weixin

 

拷贝ec-canvs文件夹到小程序里面

index.js里面的写法

import * as echarts from "../../components/ec-canvas/echarts"
const app = getApp();
function initChart(canvas, width, height, dpr) {
  const chart = echarts.init(canvas, null, {
    width: width,
    height: height,
    devicePixelRatio: dpr 
  });
  canvas.setChart(chart);
  var option = {
    backgroundColor: "#ffffff",
    series: [{
      label: {
        normal: {
          fontSize: 14
        }
      },
      type: 'pie',
      center: ['50%', '50%'],
      radius: ['20%', '40%'],
      data: [{
        value: 55,
        name: '北京'
      }, {
        value: 20,
        name: '武汉'
      }, {
        value: 10,
        name: '杭州'
      }, {
        value: 20,
        name: '广州'
      }, {
        value: 38,
        name: '上海'
      }]
    }]
  };
  chart.setOption(option);
  return chart;
}

Page({
  /**
   * 页面的初始数据
   */
  data: {
    ec: {onInit: initChart}
  }
})

index.json里面的写法

{
  "usingComponents": {
    "ec-canvas":"../../components/ec-canvas/ec-canvas"
  }
}

页面的写法

<view class="chart">
      <ec-canvas id="mychart-dom-pie" canvas-id="mychart-pie" ec="{{ ec }}"></ec-canvas>
    </view>

样式大小控制

.chart{
  width: 100%;
  height: 300px;
}
ec-canvas {width: 100%;height: 100%;}

效果图