Popup Box with Link to other google Document in Google Document - google-apps-script

Question

I have a script that I run from the menu of a google document. It essentially functions like this one: https://webapps.stackexchange.com/questions/47173/how-to-automatically-open-a-created-text-document-after-it-being-created/47649#47649.
I want a function that is similar the one in the link above except that the popup with the link is shown in a google doc rather than a google spreadsheet. That part of my script looks like this (title and url are defined above that part):
var docnew = DocumentApp.getActiveDocument();
var app = UiApp.createApplication().setTitle("Open Doc")
.setHeight(50).setWidth(400);
var vPanel = app.createVerticalPanel().add(app.createAnchor(title, url));
app.add(vPanel);
docnew.show(app);
I then get the following error. "TypeError: Funktion show in Objekt Document nicht gefunden", which is German and means "TypeError: Function show not found in object Document".
Can somebody help me with this?
Thanks a lot in advance.
Best,
Phil

Answer 1

The show method works only in spreadsheets, in Google Documents (and also in the new version of spreadsheets) you can use this code :
SpreadsheetApp.getUi().showModalDialog(argument);
The documentation shows some examples.
Your code snippet would be like this :
function showUi(){
var docnew = DocumentApp.getActiveDocument();
var app = UiApp.createApplication()
.setHeight(50).setWidth(400);
var vPanel = app.createVerticalPanel().add(app.createAnchor(title, url));
app.add(vPanel);
DocumentApp.getUi().showModelessDialog(app,"Open Doc");
}