How to change the text of a tabPanel using GAS - google-apps-script

Question

Is it possible to change the text of a page of a tabPanel and/or to setVisible() in a UiApp using GAS?
EDIT-1
To clarify my question :
function doGet()
{
var app = UiApp.createApplication();
var tabPanel = app.createTabPanel().setId('AAA');
var horPanel = app.createHorizontalPanel().setId('XXX').setSize(500, 400);
tabPanel.add(horPanel, 'YYY');
app.add(tabPanel);
return app;
}
I want to change change the text 'YYY' into something else at any time after the user sees the panels.

Answer 1

The individual panels are not available as separate objects, you can't change their properties neither hide them individually so I'm afraid what you are trying won't be possible.
The only thing you can do is select one of them, that's about all.
To get the same functionality I use vertical panels and handlers like in this example... it is entirely composed of "normal" panels and I can do what I want with it...
EDIT : handlers to switch panels :
//Panel Handlers
var pHandler1 = app.createClientHandler()
.forEventSource().setStyleAttribute('color','blue')
.forTargets(mainPanel[0]).setVisible(true)
.forTargets(mainPanel[1],mainPanel[2],mainPanel[3]).setVisible(false)
.forTargets(button[1],button[2],button[3]).setStyleAttribute('color','white')
button[0].addClickHandler(pHandler1)
var pHandler2 = app.createClientHandler()
.forEventSource().setStyleAttribute('color','blue')
.forTargets(mainPanel[1]).setVisible(true)
.forTargets(mainPanel[0],mainPanel[2],mainPanel[3]).setVisible(false)
.forTargets(button[0],button[2],button[3]).setStyleAttribute('color','white')
button[1].addClickHandler(pHandler2)
var pHandler3 = app.createClientHandler()
.forEventSource().setStyleAttribute('color','blue')
.forTargets(mainPanel[2]).setVisible(true)
.forTargets(mainPanel[0],mainPanel[1],mainPanel[3]).setVisible(false)
.forTargets(button[0],button[1],button[3]).setStyleAttribute('color','white')
button[2].addClickHandler(pHandler3)
var pHandler4 = app.createClientHandler()
.forEventSource().setStyleAttribute('color','blue')
.forTargets(mainPanel[3]).setVisible(true)
.forTargets(mainPanel[0],mainPanel[1],mainPanel[2]).setVisible(false)
.forTargets(button[0],button[1],button[2]).setStyleAttribute('color','white')
button[3].addClickHandler(pHandler4)
image of another app using this feature :

Answer 2

I accomplished this not by adding strings to the tab, but used a Label instead. I could use the id of the label later to tweak the content.
var horPanel = app.createHorizontalPanel().setId('XXX').setSize(500, 400);
var horLabel = app.createLabel('YYY').setStyleAttributes({fontWeight: 'bold', color: 'red'}).setId('xxxLabel');
tabPanel.add(horPanel, horLabel);
In the call back:
var callBackHorLabel = app.getElementById('xxxLabel');
callBackHorLabel.setText('ZZZ').setStyleAttributes({color: 'inherit'});
There may be better ways to deal with the CSS of created label to make it match the default label, but I was too lazy to research it. Hence, the fontWeight.