Sencha Touch Store With Date Field

I have a Model with Date field and Store which loads from XML with same date field as string. Would the sencha parse it to Date automatically or I would need to do that manually?

Ext.regModel('News', {
    idProperty: 'Id',
    fields: [
        { name: 'Id', type: 'int' },
        { name: 'Title', type: 'string' },
        { name: 'PostedOn', type: 'date' },
        { name: 'PostedBy', type: 'string' },
        { name: 'Details', type: '开发者_开发技巧string' }
    ]
});

var newsRemoteStore = new Ext.data.Store({
    model: 'News',
    sorters: [{
        property: 'PostedOn',
        direction: 'DESC'
    }],
    proxy: {
        type: 'ajax',
        url: BaseURL + 'News.php',
        reader: {
            type: 'xml',
            root: 'News',
            record: 'New'   
        }
    },
    getGroupString: function(record) {
        if (record && record.data.PostedOn) {
            return record.get('PostedOn').toDateString();
        }
        else {
            return '';
        }
    }
});

I am asking because the Date field is empty even though there is date in xml response e,g.

<PostedOn>2011-07-04 16:00:19</PostedOn>

Version 1.1 of Sencha Touch supports auto, string, int, float, boolean & date (refer to the Sencha Touch 1.1 API Docs

No, sencha only support 4 data types: int, float, string and auto.

You should set the date field as string and then have it converted in to a date object in the getGroupString to compare it to another date object. Read all about it here: http://www.sencha.com/blog/ext-js-4-anatomy-of-a-model