CustomTreeDataEntry

private class CustomTreeDataEntry extends TreeDataEntry {
    CustomTreeDataEntry(String id, String parent, String product, Integer value) {
        super(id, parent, value);
        setValue("product", product);
    }

    CustomTreeDataEntry(String id, String parent, String product) {
        super(id, parent);
        setValue("product", product);
    }
}

TreeMapChart

...

List<DataEntry> data = new ArrayList<>();
data.add(new CustomTreeDataEntry("Products by Revenue", null, "Products by Revenue"));
data.add(new CustomTreeDataEntry("Fruits", "Products by Revenue", "Fruits", 692000));
data.add(new CustomTreeDataEntry("Vegetables", "Products by Revenue", "Vegetables", 597000));
data.add(new CustomTreeDataEntry("Dairy", "Products by Revenue", "Dairy", 1359000));
data.add(new CustomTreeDataEntry("Meat", "Products by Revenue", "Meat", 596000));

treeMap.setData(data, TreeFillingMethod.AS_TABLE);

// Do not forget to indicate fields to return (product, value)
treeMap.setOnClickListener(new ListenersInterface.OnClickListener(new String[]{ "product", "value" }) {
    @Override
    public void onClick(Event event) {
        Toast.makeText(TreeMapChartActivity.this, event.getData().get("product") + ":" + event.getData().get("value"), Toast.LENGTH_SHORT).show();
    }
});

...