How to make Finder "Open With" work for my application (Xcode, OS X)?

Question

I created an application that can play audio files. This in itself works great, as well as drag and drop from the search engine into my application.

What I would like is that people can use my application from Finder using the Open With menu (or even allow them to set my application by default for a specific file type)

After a great search, I found that I had to set the document type in Xcode ( Edit Information Property Lists ) I successfully added a type called “Music file”, with UTI 'public.mp3' When I right-click the MP3 file, my application displayed in the "Open With" menu. Trying to use it, my application opens, but the warning message “Cannot open the document. The application cannot open files in the Music file format” appears

It does not seem to be passed through the command line, as is the case with Windows. My application supports drag & drop from Finder, and it works fine too.

I don't know where to look further, so it would be great if someone could point me in the right direction. My application does not use NSDocument, so the Class field is not suitable for me. I think (and according to the docs, this field is not required, but it does not say how to handle it without a class)

Answer 1

Do you implement application:openFile: in your application? This is the method that will be called when your application is prompted to open the file from Finder. If it is not implemented or does not return YES , then the structure will consider that the file was not successfully opened and inform the user about it.