Echarts利用多X轴实现七天天气预报效果

UI设计图
Echarts示例效果
前言
示例代码
最终效果

UI设计图

Echarts示例效果

前言

对于UI给出的设计图，各个气象网站都有类似的效果，实现方式大可归为两种：

网格布局+图表框架绘制温度曲线；
网格布局+canvas自绘温度曲线；

这两种实现方式的共同点都是将曲线和上面的描述文字拆分开来，这样做难点是要实现日期图标部分和气温曲线部分的自适应对齐。因为我CSS经验相对比较薄弱，并且使用Echarts图表框架相对较多，所以决定尝试使用Echarts（版本：4.6.0）来实现上面的效果。查看文档后发现Echarts支持多X轴和富文本显示，可以通过调整X轴偏移量来控制显示位置，同时富文本支持设置背景图标，可以用来显示天气图标。一番测试后得到下面的示例代码。

示例代码

下面这段代码可以考入Echarts直接运行：

var option = {grid: {show: true,backgroundColor: 'transparent',opacity: 0.3,borderWidth: '0',top: '180',bottom: '0'},tooltip: {trigger: 'axis'},legend: {show: false},xAxis: [// 日期{type: 'category',boundaryGap: false,position: 'top',offset: 130,zlevel: 100,axisLine: {show: false},axisTick: {show: false},axisLabel: {interval: 0,formatter: ['{a|{value}}'].join('\n'),rich: {a: {// color: 'white',fontSize: 18}}},nameTextStyle: {},data: ["25日","26日","27日","28日","29日","30日","31日"]},// 星期{type: 'category',boundaryGap: false,position: 'top',offset: 110,zlevel: 100,axisLine: {show: false},axisTick: {show: false},axisLabel: {interval: 0,formatter: ['{a|{value}}'].join('\n'),rich: {a: {// color: 'white',fontSize: 14}}},nameTextStyle: {fontWeight: 'bold',fontSize: 19},data: ["周一","周二","周三","周四","周五","周六","周日"]},// 天气图标{type: 'category',boundaryGap: false,position: 'top',offset: 20,zlevel: 100,axisLine: {show: false},axisTick: {show: false},axisLabel: {interval: 0,formatter: function(value, index) {return '{' + index + '| }\n{b|' + value + '}'},rich: {0: {backgroundColor: {// image: require('@/assets/weather_icon/' + this.weatherIconDic[this.weatherdata.weather[0]] + '.png')image: 'https://d.scggqx.com/forecast/img/小雨.png'},height: 40,width: 40},1: {backgroundColor: {// image: require('@/assets/weather_icon/' + this.weatherIconDic[this.weatherdata.weather[1]] + '.png')image: 'https://d.scggqx.com/forecast/img/小雨.png'},height: 40,width: 40},2: {backgroundColor: {// image: require('@/assets/weather_icon/' + this.weatherIconDic[this.weatherdata.weather[2]] + '.png')image: 'https://d.scggqx.com/forecast/img/阴.png'},height: 40,width: 40},3: {backgroundColor: {// image: require('@/assets/weather_icon/' + this.weatherIconDic[this.weatherdata.weather[3]] + '.png')image: 'https://d.scggqx.com/forecast/img/小雨.png'},height: 40,width: 40},4: {backgroundColor: {// image: require('@/assets/weather_icon/' + this.weatherIconDic[this.weatherdata.weather[4]] + '.png')image: 'https://d.scggqx.com/forecast/img/多云.png'},height: 40,width: 40},5: {backgroundColor: {// image: require('@/assets/weather_icon/' + this.weatherIconDic[this.weatherdata.weather[5]] + '.png')image: 'https://d.scggqx.com/forecast/img/小雨.png'},height: 40,width: 40},6: {backgroundColor: {// image: require('@/assets/weather_icon/' + this.weatherIconDic[this.weatherdata.weather[6]] + '.png')image: 'https://d.scggqx.com/forecast/img/小雨.png'},height: 40,width: 40},b: {// color: 'white',fontSize: 12,lineHeight: 30,height: 20}}},nameTextStyle: {fontWeight: 'bold',fontSize: 19},// data: this.weatherdata.weatherdata: ["小雨","小雨","阴","小雨","多云","小雨","小雨"]}],yAxis: {type: 'value',show: false,axisLabel: {formatter: '{value} °C',color: 'white'}},series: [{name: '最高气温',type: 'line',data: ["16.3","16.2","17.6","14.2","17.6","15.7","14.3"],symbol: 'emptyCircle',symbolSize: 10,showSymbol: true,smooth: true,itemStyle: {normal: {color: '#C95843'}},label: {show: true,position: 'top',// color: 'white',formatter: '{c} °C'},lineStyle: {width: 1,// color: 'white'},areaStyle: {opacity: 1,color: 'transparent'}},{name: '最低气温',type: 'line',data: ["13.4","12.8","13.5","12.5","12.4","13.2","13"],symbol: 'emptyCircle',symbolSize: 10,showSymbol: true,smooth: true,itemStyle: {normal: {color: 'blue'}},label: {show: true,position: 'bottom',// color: 'white',formatter: '{c} °C'},lineStyle: {width: 1,// color: 'white'},areaStyle: {opacity: 1,color: 'transparent'}}]}

上面的代码，最难的部分就是天气图标的设置，由于axisLabel的formatter方法中的value值没法在富文本中使用，所以这里在formatter方法中将value的下标设置成了富文本中的css名，然后在设置天气图标时使用下标获取需要显示的图标名称。

// axisLabel的formatter方法
formatter: function(value, index) {return '{' + index + '| }\n{b|' + value + '}'
}// axisLabel的rich方法
rich: {index: {backgroundColor: {image: require('@/assets/weather_icon/' + this.weatherIconDic[this.weatherdata.weather[index]] + '.png')},height: 40,width: 40}}

注：
1、this.weatherIconDic是我本地定义的一个天气图标的数据字典。（如：{ ‘晴’: ‘a00’, ‘多云’: ‘a01’, ‘阴’: ‘a02’, ‘阵雨’: ‘a03’, ‘雷阵雨’: ‘a04’, ‘冰雹’: ‘a05’, ‘雨夹雪’: ‘a06’, ‘小雨’: ‘a07’, ‘中雨’: ‘a08’, ‘大雨’: ‘a09’, ‘暴雨’: ‘a10’, ‘大暴雨’: ‘a11’, ‘特大暴雨’: ‘a12’, ‘阵雪’: ‘a13’, ‘小雪’: ‘a14’, ‘中雪’: ‘a15’, ‘大雪’: ‘a16’, ‘暴雪’: ‘a17’, ‘雾’: ‘a18’, ‘冻雨’: ‘a19’, ‘沙尘暴’: ‘a20’, ‘小到中雨’: ‘a21’, ‘中雨-大雨’: ‘a22’, ‘大雨-暴雨’: ‘a23’, ‘暴雨-大暴雨’: ‘a24’, ‘大暴雨-特大暴雨’: ‘a25’, ‘小雪-中雪’: ‘a26’, ‘中雪-大雪’: ‘a27’, ‘大雪-暴雪’: ‘a28’, ‘浮尘’: ‘a29’, ‘扬沙’: ‘a30’, ‘强沙尘暴’: ‘a31’ }）
2、this.weatherdata.weather是后端传回来的天气类型。（如：[“小雨”,“小雨”,“阴”,“小雨”,“多云”,“小雨”,“小雨”]）

最终效果