How to use renderer feature easily?
Hi, i have read a lot about renderers and i think it is much more complicated than converters and validator for example.
For example i would like that the inputText that come by default with jsf don't be gray but red. I know that i can fix its css attributes and every thing ok, but what i want is that when i pick on the component toolbar the inputText and drag it into the page the component shows itself red.
So, to do that i have to write a Renderer subclass, define a new jsp tag and its handler class, i think this is a lot of work just to change a default color.
There is another way to do that?
I think for instace, extend the default renderer class of the inputText component of jsf and in some way define the new color the component will be rendered.
[793 byte] By [
maykella] at [2007-10-3 0:02:44]
Hi,
i had a similar problem. I wanted to render the rows and columns of my dataTable dependend on the underlying data. So i just did what you mentioned:
Extend the renderer for this component and decide what to do to its attributes.
Example:
public void encodeChildren(FacesContext context, UIComponent component)
throws IOException
{
if(context == null || component == null)
throw new NullPointerException(Util.getExceptionMessageString("com.sun.faces.NULL_PARAMETERS_ERROR"));
if(log.isDebugEnabled())
log.debug("Begin encoding children " + component.getId());
if(!component.isRendered())
{
String columnClasses[] = getColumnClasses(data);
int columnStyle = 0;
int columnStyles = columnClasses.length;
String AllrowClasses[] = getRowClasses(data);
// Clean AllrowClasses for iteratable rowStyles (without 'Feiertage')
String rowClasses[] = shiftStylesforActWeekday(AllrowClasses,data);
do
{
if(rows > 0 && ++processed > rows)
break;
...
// If act. row is 'Feiertag' include style for all columns for this row
columnCount++;
if ((tagN != null && !tagN.equalsIgnoreCase(""))|| (tagS != null && !tagS.equalsIgnoreCase("")&& isSaarWorker))
//**
if(columnStyles > 0)
{
writer.writeAttribute("class", columnClasses[columnStyle++], "columnClasses");
if(columnStyle >= columnStyles)
columnStyle = 0;
}
...
// Insert extra row after "So"
if (wtag.equalsIgnoreCase("So")){
InsertExtraRow(writer, columnCount);
}
} while(true);
...
I had to change the column and rowClasses array depending which row is first in dataTable. So i shift this array and the renderer uses the shifted array to style each row and column.
I hope that may help!? Regards,
ak
Hi,
first you have to determine which component to render with which renderer:
<renderer>
<component-family>javax.faces.Data</component-family>
<renderer-type>javax.faces.Table</renderer-type>
<renderer-class>de.wfm.tag.MyUIDataTableRenderer
</renderer-class>
</renderer>
After that you implement the mentioned renderer "MyUIDataTableRenderer" in the specified location "de.wfm.tag.MyUIDataTableRenderer". I chose to extend from "HtmlBasicRenderer". The hardest thing will be to implement the behaviour of your renderer. But perhaps you find the basic implementation somewhere to have a look on (myFaces?).
Good luck, regards,
ak
