Create new file with custom file extension?

How can I create a new file with a file format of say .kuy.This file would be holding encrypted data. And then later I could choose tha开发者_如何学JAVAt file with extension .kuy to decrypt. So if I encrypted soundfile.aup, the encrypted file would be soundfile.aup.kuy, then the user would proceed to decrypting that file in which case the output would be soundfile.aup.

Thank you,

Bobby

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You can assign a file extension to your application by going to your Target's info window and selecting the Properties tab:

After that, you just need to add your desired extension when you save a file.

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As Steve suggests, first you have to create a custom file format. After that, whenever a custom file gets open - double click or whatever - its path will be passed to application:openFile:. http://developer.apple.com/library/mac/documentation/Cocoa/Reference/NSApplicationDelegate_Protocol/Reference/Reference.html#//apple_ref/doc/uid/TP40008592-CH1-SW29

Once you have the path, do your logic and you should be fine.