How can I create a document-based application that cannot create a new document?

Question

I have a document-based application that is designed to process existing documents, not to create new documents.

How do I prevent the application from creating a new, blank document when launched by opening it from the Finder?

Answer 1

There is an NSApplication delegate protocol method you can implement.

 - (BOOL)applicationShouldOpenUntitledFile:(NSApplication *)sender {
    return NO;
}

Here's the documentation

Answer 2

Depending on what you are specifically doing, you might want to override newDocument: or applicationOpenUntitledFile: or otherwise stop the user from invoking it via the File->New menu.

However, the answer above, using the delegate method applicationShouldOpenUntitledFile: will handle the common situations where you'd need that behavior.