Question

not sure that that is a good title …

I can get code behind a button to:

TabBar.activeTab.setTitle("New Tab");

but I need to do something like:

TabBar.activeTab.items = { title: "New Tab"
};

so I can eventually automate several tab properties in a loop:

TabBar.activeTab.items = { [key]: [value]
};

Am I correct in thinking config and items can only be used on construct()? Is there a way of doing the above? tia.

Answer 1

It depends on the implementation of the component and config property in question whether it can simply be set or requires a method call to be applied.

You are correct that in ExtJs many config properties are interpreted at construction time. Some are interpreted at render time. Once an Ext.Component is rendered almost all properties require an explicit method call to be applied correctly.

In general, I recommend to always use a method call to change a property after construction time if available in order to not break the inner workings of the component. If you look at the implementation of Ext.panel.Panel#setTitle you can see that there is a lot of stuff going on under the hood, e.g. event firing, etc.

ExtJs 4 configuration

Ext 4 introduced an explicit ‘config’ mechanism that might serve your purpose. However, my understanding is that most ExtJs components are not (yet?) using it.

Check out ‘2. Configuration’ in the ExtJs Class System Guide

Create objects from xtype/config literals

If you want to add new components to a container (e.g. tabs to a tab panel) it would be rather easy to accomplish.

Use Ext.ComponentManager#create (see [docs][2]) to create an actual component object/instance from your config literal.

Ext.container.Container#add actually calls this method internally, so you can simply pass config objects to the add method.

If you want to remove or add tabs to a panel, there is now way around calling the proper methods.

applyConfig()

Of course you could always implement your own applyConfig method that supports changing certain component configuration properties at runtime by ‘translating’ the config into the proper method calls.