How to right-align, v-center "buy" button in Ext.dataview.component.ListItem?

I am trying to create a buy button in a list view like the iTunes store on iOS.

IMG_0710.jpg

I am able to get the button in there but it is 100% height, has no right-margin, and the text isn't centered in it (see image below).

2015-02-21_13-25-42.jpg

Here is how I'm creating the ListItem:

Code:

Ext.define('Speakeasy.view.DeckItem', {
    extend: 'Ext.dataview.component.ListItem',
    alias: 'widget.deckitem',
    config: {
        layout: {
            type: 'hbox'
        },
        hideAnimation: 'slideOut',
        disabled: true,
        items: [
            {
                xtype: 'component',
                itemId: 'titleCmp',
                __itemTpl: new Ext.XTemplate(
                    '<tpl for=".">',
                    '<tpl if="isPurchased">',
                    '<span class="deck-price">{price}</span>',
                    '</tpl>',
                    '</tpl>'
                ),
                docked: 'left'
            },
            {
                xtype: 'button',
                text: 'Buy',
                itemId: 'buy-button',
                cls: 'buy-button',
                hideAnimation: 'fadeOut',
                showAnimation: 'slideIn',
                docked: 'right',
                handler: function(x, e) {
                    var sku = this.getParent().getRecord().get('sku');
                    decksController.Purchase(sku);
                    e.stopEvent();
                }
            }
        ]
    },
});

Ext.define('Speakeasy.view.Decks', {
    extend: 'Ext.List',
    xtype: 'decks',
    alias: 'widget.decksview',
    requires: [
        'Ext.TitleBar',
        'Ext.data.Store'
    ],
    config: {
        itemId: 'decksview',
        tabBarPosition: 'bottom',
        layout: {
            type: 'fit'
        },
        defaultType: 'deckitem',
//        useComponents: true,                                                                                          
        grouped: true,

Thanks you so much!



How to right-align, v-center "buy" button in Ext.dataview.component.ListItem?