How to use ECharts to load data asynchronously in WeChat applet

This article mainly introduces the method of using ECharts to load data asynchronously in the WeChat applet. It is very good and has certain reference value. Friends in need can refer to the

official website examples are all synchronous. For how to introduce and synchronize the demo, please go to the official website

<view class="container">
 <ec-canvas id="mychart-dom-multi-bar" canvas-id="mychart-multi-bar" ec="{{ ecBar }}"></ec-canvas>
 <ec-canvas id="mychart-dom-multi-scatter" canvas-id="mychart-multi-scatter" ec="{{ ecScatter }}"></ec-canvas>
</view>

import * as echarts from '../../ec-canvas/echarts';
Page({
 data: {
  ecBar: {
   lazyLoad: true // 延迟加载
  },
  ecScatter: {
   lazyLoad: true 
  }
 },
 onLoad(){
  this.barComponent = this.selectComponent('#mychart-dom-multi-bar');
  this.scaComponnet = this.selectComponent('#mychart-dom-multi-scatter');
  this.init_bar();
  this.init_sca();
 },
 init_bar: function (){
  this.barComponent.init((canvas, width, height) => {
   // 初始化图表
   const barChart = echarts.init(canvas, null, {
    width: width,
    height: height
   });
   barChart.setOption(this.getBarOption());
   // 注意这里一定要返回 chart 实例，否则会影响事件处理等
   return barChart;
  });
 },
 init_sca: function () {
  this.scaComponnet.init((canvas, width, height) => {
   // 初始化图表
   const scaChart = echarts.init(canvas, null, {
    width: width,
    height: height
   });
   scaChart.setOption(this.getScaOption());
   // 注意这里一定要返回 chart 实例，否则会影响事件处理等
   return scaChart;
  });
 },
 getBarOption:function(){
  //return 请求数据
  return {
   color: ['#37a2da', '#32c5e9', '#67e0e3'],
   tooltip: {
    trigger: 'axis',
    axisPointer: {      // 坐标轴指示器，坐标轴触发有效
     type: 'shadow'    // 默认为直线，可选为：'line' | 'shadow'
    }
   },
   legend: {
    data: ['热度', '正面', '负面']
   },
   grid: {
    left: 20,
    right: 20,
    bottom: 15,
    top: 40,
    containLabel: true
   },
   xAxis: [
    {
     type: 'value',
     axisLine: {
      lineStyle: {
       color: '#999'
      }
     },
     axisLabel: {
      color: '#666'
     }
    }
   ],
   yAxis: [
    {
     type: 'category',
     axisTick: { show: false },
     data: ['汽车之家', '今日头条', '百度贴吧', '一点资讯', '微信', '微博', '知乎'],
     axisLine: {
      lineStyle: {
       color: '#999'
      }
     },
     axisLabel: {
      color: '#666'
     }
    }
   ],
   series: [
    {
     name: '热度',
     type: 'bar',
     label: {
      normal: {
       show: true,
       position: 'inside'
      }
     },
     data: [300, 270, 340, 344, 300, 320, 310]
    },
    {
     name: '正面',
     type: 'bar',
     stack: '总量',
     label: {
      normal: {
       show: true
      }
     },
     data: [120, 102, 141, 174, 190, 250, 220]
    },
    {
     name: '负面',
     type: 'bar',
     stack: '总量',
     label: {
      normal: {
       show: true,
       position: 'left'
      }
     },
     data: [-20, -32, -21, -34, -90, -130, -110]
    }
   ]
  };
 },
 getScaOption:function(){
  //请求数据 
  var data = [];
  var data2 = [];
  for (var i = 0; i < 10; i++) {
   data.push(
    [
     Math.round(Math.random() * 100),
     Math.round(Math.random() * 100),
     Math.round(Math.random() * 40)
    ]
   );
   data2.push(
    [
     Math.round(Math.random() * 100),
     Math.round(Math.random() * 100),
     Math.round(Math.random() * 100)
    ]
   );
  }
  var axisCommon = {
   axisLabel: {
    textStyle: {
     color: &#39;#C8C8C8&#39;
    }
   },
   axisTick: {
    lineStyle: {
     color: &#39;#fff&#39;
    }
   },
   axisLine: {
    lineStyle: {
     color: &#39;#C8C8C8&#39;
    }
   },
   splitLine: {
    lineStyle: {
     color: &#39;#C8C8C8&#39;,
     type: &#39;solid&#39;
    }
   }
  };
  return {
   color: ["#FF7070", "#60B6E3"],
   backgroundColor: &#39;#eee&#39;,
   xAxis: axisCommon,
   yAxis: axisCommon,
   legend: {
    data: [&#39;aaaa&#39;, &#39;bbbb&#39;]
   },
   visualMap: {
    show: false,
    max: 100,
    inRange: {
     symbolSize: [20, 70]
    }
   },
   series: [{
    type: &#39;scatter&#39;,
    name: &#39;aaaa&#39;,
    data: data
   },
   {
    name: &#39;bbbb&#39;,
    type: &#39;scatter&#39;,
    data: data2
   }
   ],
   animationDelay: function (idx) {
    return idx * 50;
   },
   animationEasing: &#39;elasticOut&#39;
  };
 },
});

Note: When loading asynchronously, the ec-canvas tag must be loaded and displayed before this.scaComponnet.init, otherwise an error will be reported.

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