echarts重写图例点击事件

echarts version: 3.1.2

修改图例点击事件样例代码：

• 当第一次点击图例时，只显示点击的图例。
• 当还剩一个图例被取消选中后，自动全选中所有图例。

  var triggerAction = function(action, selected) { legend = []; for ( name in selected) { if (selected.hasOwnProperty(name)) { legend.push({name: name}); } } myChart.dispatchAction({ type: action, batch: legend }); }; var isFirstUnSelect = function(selected) { var unSelectedCount = 0; for ( name in selected) { if (!selected.hasOwnProperty(name)) { continue; } if (selected[name] == false) { ++unSelectedCount; } } return unSelectedCount==1; }; var isAllUnSelected = function(selected) { var selectedCount = 0; for ( name in selected) { if (!selected.hasOwnProperty(name)) { continue; } // 所有 selected Object 里面 true 代表 selected， false 代表 unselected if (selected[name] == true) { ++selectedCount; } } return selectedCount==0; }; myChart.on('legendselectchanged', function(obj) { var selected = obj.selected; var legend = obj.name; // 使用 legendToggleSelect Action 会重新触发 legendselectchanged Event，导致本函数重复运行 // 使得 无 selected 对象 if (selected != undefined) { if (isFirstUnSelect(selected)) { triggerAction('legendToggleSelect', selected); } else if (isAllUnSelected(selected)) { triggerAction('legendSelect', selected); } } });