creating a tab panel in extjs4 with different stores that loads only upon the particular tab is selected - extjs4

Question

I'm using extjs4 and I'm trying to create a tab panel, that each tab has a different grid that loads data from a store. (each grid different store)
I would like to load the particular store only when the user clicks on the respective tab.
I don't see how I can catch the user click on the panel.
How I can do that?

Answer 1

I had a similar performance loading issue and failed to solve it with deferredRender. You have to add the event activate for the tab you want to load when the tab is activated :
{
title: 'tab2',
bodyPadding: 10,
html : 'A simple tab',
listeners: {
'activate' : function(){
store2.load();
},
}
}
Worked fine for me even if it's a temporary solution. Extjs 4.1 should improve loading/rendering performances. We'll see.

Answer 2

You can activate the panel by placing setActiveItem() in tab handler.

Answer 3

Ok, I figured out, I just needed to have deferredRender=true and to add the respective store.load() on the beforerender event on every tab:
var lowerTabPanel = Ext.create('Ext.tab.Panel', {
deferredRender: true,
items: [
{
title: 'tab1',
bodyPadding: 10,
html : 'A simple tab',
listeners: {
'beforerender' : function(){
store1.load();
},
}
},
{
title: 'tab2',
bodyPadding: 10,
html : 'A simple tab',
listeners: {
'beforerender' : function(){
store2.load();
},
}
},
]
});

Answer 4

Ext.TabPanel has config option deferredRender. May be it helps you.
Documentation:
true by default to defer the rendering of child items to the browsers DOM until a tab is activated. false will render all contained items as soon as the layout is rendered. If there is a significant amount of content or a lot of heavy controls being rendered into panels that are not displayed by default, setting this to true might improve performance.
Update: Also look at autoLoad config option in Ext.data.JsonStore, it should be false.