init: function() {

            if (!this.oFragment) {
                this.oFragment = sap.ui.xmlfragment("demo_plugin.fragment.Welcome", this);
                sap.ui.getCore().byId("closeBtn").attachPress(function() {
                    this.oFragment.close();
                }.bind(this));
            }

            this.oFragment.attachAfterClose(function() {
                this.destroy();
            });
            this.oFragment.open();

        }