Navigation.js

Ext.define('Mba.ux.Viewport.Navigation', {
    singleton: true,
    alternateClassName: 'viewport.navigation',
    config: {
        confirmCloseApp: true,
        backOverride: null,
        navigationStack: []
    },
    constructor : function (config) {
        this.initConfig(config);
        this.callParent([config]);
    },
    activateView: function(viewXtype, options, animation) {
        var view;

        if(!(view = Ext.Viewport.child(viewXtype))) {
            view = Ext.Viewport.add({xtype: viewXtype});
        }

        if(!animation && view.getAnimation) {
            animation = view.getAnimation();
            animation.direction = 'left';
        }

        for(var o in options) {
            view['set' + Ext.String.capitalize(o)](options[o]);
        }

        if (view.isInnerItem()) {
            if(animation) {
                Ext.Viewport.animateActiveItem(view, animation);
            } else {
                Ext.Viewport.setActiveItem(view);
            }
        } else {
            view.show();
        }

        this.orderHistory(viewXtype);

        return view;
    },
    clear: function() {
        this.setNavigationStack([]);
    },
    orderHistory: function(viewXtype) {
        var stack = this.getNavigationStack(),
            pos;

        if((pos = stack.indexOf(viewXtype)) >= 0) {
            stack.splice(pos, 1);
        }

        stack.push(viewXtype);
        this.setNavigationStack(stack);
    },
    back: function() {
        var stack = this.getNavigationStack();

        if(stack.length <= 1) {return false;}

        var animation = this.getAnimation(stack.pop());

        if(animation) {
            animation.direction = 'right';
        }

        this.activateView(stack.pop(), null, animation);

        return true;
    },
    getAnimation: function(viewXtype) {
        var view = Ext.Viewport.child(viewXtype);

        return view.getAnimation ? view.getAnimation() : null;
    },
    clearNavitaionStack: function() {
        this.setNavigationStack([]);
    },
    clearBackOverride: function() {
        this.setBackOverride(null);
    }
});