Getting our first app on the Mac App Store – the pitfalls
Around lunch today, I got a simple but - if I may say so - great idea for an app that I need on my Mac (I can't tell you what it is just yet, you'll have to wait for it to be released in the app store 
.
I figured that it would be a great way to try out Cocoa development for Mac, as opposed to the regular Cocoa Touch development I spend most of my time on nowadays. Also, a great opportunity to learn more about the Mac App Store.
Development was easy!
So I started a project in XCode and quickly read up on how to implement the Mac OS X features I needed. The Mac dev center docs turned out to be a pleasant experience. And people have been developing Cocoa apps for years, so it wasn't all too difficult to find online help whenever I ran into some problems. The development of the app itself was done in about 15-30 minutes (!).
The major gripe was - of course! - the submission process to the App Store. Joining the Mac developer program was surprisingly easy if you've already got an iOS developer account, but the big confusion started when I tried to get my new certificates.
Generating certificates with Chrome returns "Invalid certificate" error
I should've learned by now, but I always get some kind of headache when trying to get the proper distribution certificates for iOS (and now Mac) apps.
Even though I read the Mac App Store instructions thoroughly, I couldn't get it right when trying to generate a new certificate, using the Developer Certificate Utility. As I banged my head against the table, I remembered that there had been problems with this before... And the solution was - and this is a tricky one - to use Safari when generating the cert, instead of Chrome (!). You have to use Safari when generating the certificate. I can live with that, but the problem is that I'm getting nothing but the message "Invalid certificate" message when trying to generate it.
But it worked in Safari, and I figured I'd better choose to generate both the Application and the Installer certificate at once, using the two checkboxes available. A certificate was generated and named something "3rd Party Mac Developer Application...".
All good, it seemed:
Generate the Application and Installation certificates separately!
Another problem occurred when I tried to "Build and Archive" the app in XCode. I couldn't. But it was an easy one, as all I had to do was to download the new Application Loader 1.1 in order to get it to build.
But when all this was done, I still couldn't upload the binary properly. There was no option to code sign the installation file (.pkg) - the only option in the drop-down was "Don't sign". I Googled and tried all kinds of different methods, but couldn't get the binary approved by iTunes Connect. I tried to generate a new certificate a couple of times, but without success.
But then I returned to the certificate creation process, and figured that maybe I need to generate one certificate at a time. So I tried that. And it turns out (!), the checkboxes weren't really checkboxes (!!). They were radio buttons (!!!). I had to uncheck the Application option and only generate the Installer certificate, which gave me a certificate I could use to sign my .pkg file and upload a valid binary.
The right way:
I cannot enough express how annoyed I can get when it comes to this entire certificate-signing-submitting-apps process. How can Apple make it so difficult?
It's gotten a lot better over the last year, but I mean; where the h**l are they UX team when they're developing these things? They're clearly not prioritizing user experience in the development section of their site...
In the end; a success
I hope someone can read this and avoid some of the pitfalls I fell into. I can strongly recommend reading the Mac Store App Submission FAQ in the developer forums. A lot of tricky questions are answered there.
But I'm still happy as I've finally managed to upload the app. Just hoping that I haven't missed anything silly in the submission process and that the app will be available soon. And that people like it, of course!
It will be very interesting to get an understanding of the Mac App Store.
Oh, and big thanks to @psilfver who designed a great looking icon for the app!
/Kristofer