<?xml version="1.0" encoding="UTF-8"?>
<window apply="org.zkoss.bind.BindComposer" 
    viewModel="@id('vm') @init('nc.noumea.mairie.appock.viewmodel.AcceuilServiceViewModel')" 
    border="none" hflex="1" vflex="1" contentStyle="overflow:auto">
                    <charts id="charts" 
                        model="@bind(vm.getCharts(charts))" title="" 
                        type="pie" onClick="@command('ouvreOnglet',chart=charts)"/>
</window>

public class AcceuilServiceViewModel{
public PieModel getCharts(@BindingParam(value = "") Charts mychart) throws Exception {
        mychart.getSeries().remove();

        PiePlotOptions plotOptions = mychart.getPlotOptions().getPie();
        plotOptions.setAllowPointSelect(true);
        plotOptions.setCursor("pointer");

        // on ajoute les différentes parties du chart
        PieModel model = new DefaultPieModel();

        List<String> listOldEating = new ArrayList<>();
        listOldEating.add("apple");
        listOldEating.add("steack");
        listOldEating.add("banana");

        List<String> listNewEating = new ArrayList<>();
        listNewEating.add("pizza");
        listNewEating.add("cheesburger");

        Map<String, List<String>> result = new TreeMap<>();
        result.put("new food", listNewEating);
        result.put("old food", listOldEating);

        Series series = mychart.getSeries();
        for (String etat : result.keySet()) {
            Point p = new Point(etat, result.get(etat).size(), "" + etat);
            series.addPoint(p);
        }
        return model;

    }

    @Command("ouvreOnglet")
    public void ouvreOnglet(@BindingParam(value = "chart") Charts mychart) {
        for (Point s : mychart.getSeries().getData()) {
            if (s.isSelected()) {
                // on recup la valeur selectionnée
                String etat = s.getDrilldown();
                Messagebox.show(etat);
            }
        }
    }
}