Sencha touch ::使TabPanel始终向左滑动

new Ext.TabPanel({
fullscreen: true,
defaults:{animation: new Ext.Anim({
    direction: \'left\',
    cover: false,
    reveal: false,

    before: function(el) {
        var curZ = el.getStyle(\'z-index\') == \'auto\' ? 0 : el.getStyle(\'z-index\'),
            zIndex = curZ + 1,
            toX = 0,
            toY = 0,
            fromX = 0,
            fromY = 0,
            elH = el.getHeight(),
            elW = el.getWidth();

        if (this.direction == \'left\' || this.direction == \'right\') {
            if (this.out == true) {
                toX = -elW;
            }
            else {
                fromX = elW;
            }
        }
        else if (this.direction == \'up\' || this.direction == \'down\') {
            //if (this.out == true) {
            //    toY = -elH;
            //}
            //else {
                fromY = elH;  //Always slide to the left???
            //}
        }

        if (this.direction == \'right\' || this.direction == \'down\') {
            toY *= -1;
            toX *= -1;
            fromY *= -1;
            fromX *= -1;
        }

        if (this.cover && this.out) {
            toX = 0;
            toY = 0;
            zIndex = curZ;
        }
        else if (this.reveal && !this.out) {
            fromX = 0;
            fromY = 0;
            zIndex = curZ;
        }

        this.from = {
            \'-webkit-transform\': \'translate3d(\' + fromX + \'px, \' + fromY + \'px, 0)\',
            \'z-index\': zIndex,
            \'opacity\': 0.99
        };
        this.to = {
            \'-webkit-transform\': \'translate3d(\' + toX + \'px, \' + toY + \'px, 0)\',
            \'z-index\': zIndex,
            \'opacity\': 1
        };
    }
})
},
items: [
    {
        title: \'Tab 1\',
        html : \'1\',
        cls  : \'card1\'
    },
    {
        title: \'Tab 2\',
        html : \'2\',
        cls  : \'card2\'
    },
    {
        title: \'Tab 3\',
        html : \'3\',
        cls  : \'card3\'
    }
]
});