extjs radiogroup before change event - extjs

Question

Could you please help me before change/check the event on ExtJS radiogroup. I want some event should check before changing the radio button based on the condition. I need to allow user to change the select another radio button if condition says false, then we need to select the old radio button only.
Please refer the below code:
Ext.application({
name: 'Fiddle',
launch: function () {
Ext.create('Ext.form.Panel', {
title: 'RadioGroup Example',
width: 300,
height: 125,
bodyPadding: 10,
renderTo: Ext.getBody(),
items: [{
xtype: 'radiogroup',
fieldLabel: 'Gender',
columns: 1,
items: [{
boxLabel: 'Male',
name: 'rb',
inputValue: '1'
}, {
boxLabel: 'Female',
name: 'rb',
inputValue: '2',
}],
listeners: {
change: function(field, newValue, oldValue, eOpts) {
console.log(newValue);
alert(newValue.rb);
},
}
}]
});
}
});
https://fiddle.sencha.com/#view/editor&fiddle/32fb

Answer 1

As mentioned in the comments, there is no beforechange event that can be used to veto a change.
Some other options are:
you can the change listener to validate the radiogroup, making it invalid if an option is selected that's not right. This way the user is passively informed that there's a problem, and they have to fix it.
you can get the behaviour you described by using the oldvalue argument, and simply setting the radio control back to the old value:
change: function(field, newValue, oldValue, eOpts) {
if (<new value isn't acceptable>) {
// Probably should let the user know why
field.setValue(oldValue);
return;
}
... any other change logic here.
}
You can also use the change listener enable and disable options pre-emptively as the form state changes, thus preventing the user from making a bad choice in the first place.