Issue with Busy indicator loading on action

Hi, 

I tried to call busy indicator on the button press and after the oData operation it should get closed.
But the problem is the "Busy indicator" is not getting loaded immediately after pressing the button.
Below is my code for loading busy indicator,
onOpenDialog: function (oEvent)
{
// instantiate dialog
if (!this._dialog)
{
this._dialog = sap.ui.xmlfragment("Travel.Create.util.BusyDialog", this);
this.getView().addDependent(this._dialog);
}

  // open dialog jQuery.sap.syncStyleClass("sapUiSizeCompact", this.getView(), this._dialog); this._dialog.open(); // simulate end of operation jQuery.sap.delayedCall(2000, this, function () { this._dialog.close(); }); }, 

handlePressSubmit:function(Draft_flag)
{
this.onOpenDialog();
/* logic for oData operation here*/
}
did i miss anything?

-Mahi