Ext.define("MyButton", {
            extend : "Ext.Button",
            text : "ckfinder",
            initComponent : function() {
                var me = this;
                Ext.apply(me, {
                    handler : me.handlerClick
                });
                me.callParent();
            },

            handlerClick : function(btn) {
                var finder = new CKFinder();
                finder.selectActionFunction = Ext.bind(btn.SetFileField, btn);
                finder.popup();
            },

            SetFileField : function(fileUrl) {
                console.log(fileUrl);
            }
        });