How to override default date format: Ext.util.Format.defaultDateFormat

Hi

I found from the SenchaTouch docs that DatePickerField.dateFormat uses the default date format:

Defaults to: Ext.util.Format.defaultDateFormat

http://ift.tt/1wweSW8

How would one go about overriding the default date format of a sencha-touch app?

I have seen threads that advise to use something along the lines of the following code:

Code:

Ext.apply(Ext.util.Format.prototype, {
            defaultDateFormat: 'd-m-Y'
        });

Where would one put this code? I've tried it in the Ext.application.launch function, which doesn't work.

Is there another way of specifying / overriding the defaultDateFormat of an app?

Thanks

-tt88