echars点击图例之后只显示当前数据其他隐藏

1. 确认echarts默认效果

echarts默认点击图例有如下效果：

当前图例显示，点击后隐藏该图例；
当前图例隐藏，点击后显示该图例。

2. 确认需要处理的事件

经过在官网查看事件后发现最合适的是legendselectchanged事件，该事件在切换图例选中状态时触发。
具体用法为：

myChart.on('legendselectchanged', params => {})

3. 将目标简单化

由于echarts本身自带是否显示影藏，那我们只需要在这个基础上优化以下两点即可：

当所有图例都不显示的时候显示全部图例；
当除了当前点击图例，其他图例都显示的时候(也就是全部显示的情况下点击了当前图例)，只显示当前图例。

4. 代码实现

myChart.on('legendselectchanged', params => {const curLegend = params.name;const allLegend = Object.keys(params.selected);const selectedArr = Object.keys(params.selected).filter(el => params.selected[el])const clearFlag = selectedArr.length === 0const onlyCur = selectedArr.length + 1 === allLegend.length && !selectedArr.includes(curLegend);if (clearFlag) {allLegend.forEach(key => {myChart.dispatchAction({type: 'legendSelect',name: key,})})}if (onlyCur) {allLegend.forEach(key => {myChart.dispatchAction({type: key === curLegend ? 'legendSelect' : 'legendUnSelect',name: key,})})}
})

4. 完整代码

<!DOCTYPE html>
<html><head><meta charset="utf-8" /><title>ECharts</title><!-- 引入刚刚下载的 ECharts 文件 --><script src="https://cdn.jsdelivr.net/npm/echarts@5.5.0/dist/echarts.min.js"></script>
</head><body><!-- 为 ECharts 准备一个定义了宽高的 DOM --><div id="main" style="height:400px;"></div><script type="text/javascript">// 基于准备好的dom，初始化echarts实例var myChart = echarts.init(document.getElementById('main'));// 指定图表的配置项和数据var option = option = {title: {text: 'Stacked Line'},tooltip: {trigger: 'axis'},legend: {data: ['Email', 'Union Ads', 'Video Ads', 'Direct', 'Search Engine']},grid: {left: '3%',right: '4%',bottom: '3%',containLabel: true},xAxis: {type: 'category',boundaryGap: false,data: ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']},yAxis: {type: 'value'},series: [{name: 'Email',type: 'line',stack: 'Total',data: [120, 132, 101, 134, 90, 230, 210]},{name: 'Union Ads',type: 'line',stack: 'Total',data: [220, 182, 191, 234, 290, 330, 310]},{name: 'Video Ads',type: 'line',stack: 'Total',data: [150, 232, 201, 154, 190, 330, 410]},{name: 'Direct',type: 'line',stack: 'Total',data: [320, 332, 301, 334, 390, 330, 320]},{name: 'Search Engine',type: 'line',stack: 'Total',data: [820, 932, 901, 934, 1290, 1330, 1320]}]
};// 使用刚指定的配置项和数据显示图表。myChart.setOption(option);myChart.on('legendselectchanged', params => {const curLegend = params.name;const allLegend = Object.keys(params.selected);const selectedArr = Object.keys(params.selected).filter(el => params.selected[el])const clearFlag = selectedArr.length === 0const onlyCur = selectedArr.length + 1 === allLegend.length && !selectedArr.includes(curLegend);if (clearFlag) {allLegend.forEach(key => {myChart.dispatchAction({type: 'legendSelect',name: key,})})}if (onlyCur) {allLegend.forEach(key => {myChart.dispatchAction({type: key === curLegend ? 'legendSelect' : 'legendUnSelect',name: key,})})}});</script>
</body></html>