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Here we describe how to implement a custom renderer for a listbox (ListitemRenderer). For the concepts about component, model and renderer, please refer to the Model-driven Display section.

When a listbox (Listbox) is assigned with a model, a default renderer is assigned too. The default renderer will assume that each list item has only one column, and it converts the data into a string directly[1]. If you want to display multiple columns or retrieve a particular field of the data, you have to implement ListitemRenderer to handle the rendering.

For example,

public class MyRenderer implements ListitemRenderer{
	public void render(Listitem listitem, Object data, int index) {
		Listcell cell = new Listcell();
		if (data instanceof String[]){
			cell.appendChild(new Label(((String[])data)[0].toString()));
		} else if (data instanceof String){
			cell.appendChild(new Label(data.toString()));
		} else {
			cell.appendChild(new Label("UNKNOW:"+data.toString()));

  1. If the listbox is assigned a template called model, then the template will be used to render the listbox. For more information, please refer to the Listbox Template section.

Version History

Last Update : 2013/11/6

Version Date Content
6.0.0 February 2012 The index argument was introduced.

Copyright © Potix Corporation. This article is licensed under GNU Free Documentation License.