How can get the child node for click event on treepanel? - extjs4

Question

Code in controller
nextPages:function()
{
var obj=Ext.getCmp('centerId');
obj.removeAll();//remove center panel to display new panel information
var myTree=Ext.getCmp('leftId');//get tree panel view
var node=myTree.getRootNode().findChild("navTree","localId",true);//for get child node
if(node){
var obj2=Ext.create('AS.view.center.Localadmin');
obj2.region='center';
obj.add(obj2);
}
Code in view:
Ext.define('AS.view.left.Left',{
extend:'Ext.tree.Panel',
alias:'widget.Left',
id:'leftId',
useArrows : true,
hideHeaders : true,
//title: 'About village',
height: 150,
root: {
itemId:'navTree',
rootVisible : false,
text:'About village',
children:[{
text:'Whats nearby?',
expanded: true,
children: [{
// id:'first',
id:'localId',
text: 'Local Administration',
leaf: true
}, {
id:'bId',
text: 'Bussiness directory',
leaf: true
},{
id:'hid',
text: 'Heritage and tourism',
leaf: true
},{
id:'eid',
text: 'Education',
leaf: true
}],
},
{
text:'classifieds',
leaf: true
},{
text:'Events',
leaf: true
}],//children1
},//root
});
I want to get the specific child node for click event and after display another panel on that click of node. Tell me how to get the child node from tree panel.
In controller I wrote a function to get the child node and then get the view on that click of specific node.