This Thursday, July 7th: Brian Papa from theSkimm, hosted by eBay

Join us this Thursday, July 7th at 7pm, for our Cocoaheads meetup!1 Our host this month is eBay, who has generously offered us pizza and beer in their beautiful Studio space (right above the Container Store on 6th Ave).

Our speaker this month is longtime Cocoaheads member Brian Papa! Brian works for The Skimm, a newsletter-based media company that has over a million and a half subscribers. When TheSkimm's app launched in April, it had over 1000 reviews in a week (!) and several of my friends told me how excited they were to buy a subscription. I personally know how big of a deal it is for users to fork over an in-app purchase for a recurring subscription, so, I have no doubt Brian's going to share a couple of interesting points he's learned.

eBay Studio
625 Avenue of Americas (6th Ave, between 18th and 19th), 3rd Floor


Heads up: Next Month

I am searching for a speaker for next month's meetup on August 11th. Let me know if you're interested!  If I don't find a speaker, we might skip August and resume our regularly scheduled program for September.  I'll let you know well in advance either way.



Yes, this breaks the second Thursday of each month rhythm. I booked a vacation for next week. Apologies!

[Venue Change: Code & Theory] June 9th with Don Coleman about Bluetooth

Happy June, CocoaHeads! We're only one week away from WWDC, we have an excellent speaker planned, and we've got a venue change for this month's meeting.

Don Coleman joins us from Philadelphia, and he's been doing a lot of work with Bluetooth Low Energy. He's a seasoned veteran on the subject, and he's given numerous talks about it!  Thursday, he'll share a few things he's learned from his experiences with Arduinos, iBeacons, and lots more.

We will not be meeting at Google this month. Code & Theory has offered to host us on June 9th at 6:30:

Code & Theory 575 Broadway, 5th Floor New York, NY 10012

They've also very graciously offered to buy us pizza, so, we won't be going out to dinner afterward. Please plan to arrive promptly at 6:30 so we can get our talk in and grab a slice and pontificate about the future Apple will bring us next week.


Our next meeting is Thursday, 3/10/16, with Sophia D'Antoine from Trail of Bits

Greetings, CocoaHeads!

Join us on Thursday, 3/10/16, for a riveting presentation from Sophia D'Antoine.  Sophia hails from Trail of Bits, a security firm in the city, and she'll talk about the product she's been working on there that offers jailbreak detection, anti-reversing of LLVM code, and a few other prevention techniques for applications that must be secure. She and the company's founder, Dan Guido, gave an excellent overview of the security space on iOS at Etsy's Code as Craft series a few weeks ago and I could not be more excited that she'll share with our group for this month. For a sneak peek on the topic matter, take a look at this blog post.

And, on a sadder note, Patsy's 23rd Street location has closed. So, for dinner after, voice your choice in this poll.




We've had a number of solid speakers and get-togethers over the past year, and I apologize for not keeping the blog up to date.  Even the meetings without a formal speaker have given us the chance to decompress around our favorite topics and provide a backchannel for some current events.

Here's what we've been talking about since July 2015:

  1. In August, after we had a chance to let WWDC sink in a bit, and caught up on a few talks, we had a lively discussion about some of the new things and things omitted.
  2. October was fresh after the tvOS announcement. We discussed some of the limitations and documentation.
  3. For our November meeting, we got an excellent demo from Bob Clair about the physics app that he'd been working on for CERN.  Eric Panchenko also gave us a walkthrough of his trivia app that he rebuilt for tvOS.
  4. I gave a demo in December of a UITableView that prepends data as the user scrolls up (as Messages does).
  5. Dennis Pilarinos from Buddybuild impressed us thoroughly with a new way to distribute Beta builds in January!
  6. For February, we tried a show-and-tell type of set up with a few demos from around the table.

Looking forward to what 2016 will bring!


July 9th: Jeremy Cohen, Facebook, and Core Data

Howdy folks! Join us this Thursday night for a rabble-rousing talk from Jeremy Cohen about what Facebook is doing for persistent storage. I know I've got a ton of questions and I'm sure you do, too — bring 'em on Thursday and we'll hash it all out.


Also, please note that Jeremy's gotta run right around 7, so we're going to do our best to start right at 6:30 on Thursday. All the details are here. See you then!

May 14th: Job Interview Trivia [UPDATED]

Technical interviews: loved by some, loathed by others, but, universally, a necessary gauntlet to vet possible coworkers to prove their worth.

Join us this Thursday, May 14th, at our usual time and place where we will *gasp* quiz each other on interview questions! Sure, there will be softball questions, certainly some hardball questions, maybe a curveball or brain teaser or two BUT there WILL BE PRIZES.

Since I'll be running this open-ended and interactive edition of CocoaHeads, this will be part trivia, and part discussion of which questions make Good Technical Interview Questions for different levels of people.

If you have any interview questions you'd like to contribute, please pass them my way before Thursday!

Post-Meeting Update

Thanks to all who made it out and suffered through 15 iOS interview questions. The good news is that I didn't grade your answers because (a) that'd be creepy and (b) I couldn't read most people's handwriting. But I could make out integers in some of their scrawl!

Here are the slides that I gave for the talk:

…and here's how each question fared. For each question, everybody rated how difficult the question was, where a 1 was for a Junior iOS Dev, 3 was Intermediate, and 5 was Expert. Here's the list sorted by the number of votes a question received to grade its expected difficulty (Junior -> Senior):

Question 1 2 3 4 5 Average
Name some of the UIApplicationDelegate protocol methods and how to use them. 6 2 0 0 0 1.25
What’s a delegate? Give an example. 6 2 0 0 0 1.25
NSArray *foo = @[@“alpha”, @“beta”, @“gamma”]; How would you add another element (@“delta”) to the foo array? 5 2 1 0 0 1.5
What are some ways that you can persist data in an app? 4 2 2 0 0 1.75
Describe what happens behind the scenes when you tap an app’s icon, you see the app open, and you press the home button. 2 5 1 0 0 1.875
How can you add a method to a class that you don’t have the code for? 3 3 2 0 0 1.875
What is a hash? 3 3 2 0 0 1.875
How do you use NSNotificationCenter? 1 5 2 0 0 2.125
What are the differences between an array and a linked list? What do you think an NSArray is? 2 4 1 1 0 2.125
When you create an object (in a running app, not while you’re writing code), where are the bytes located in memory? 2 3 3 0 0 2.125
You have a method call. By using the debugger or a print statement you determine that the method is never called even though it seems plain that it should be. What is a very likely cause? 0 4 4 0 0 2.5
Have you worked with NSOperationQueue? How does it work? 0 4 3 1 0 2.625
When responding to an NSNotification, what will happen if the notification handler executes for a long time? What can you do about it? 1 3 3 1 0 2.625
Why shouldn’t you reference self in a block? 0 1 6 1 0 3
What is an NSZombie? 0 1 3 3 1 3.5

And this is not to say that all the questions were acceptable — some of them I put strikethroughs because our group more or less voted them down to be too algorithmic or pure computer-sciency, which does not equate to a good iOS developer. This is a tricky subject: some startups will want a versatile engineer well-versed in the basics of CS, and, frankly, some excellent iOS devs have had no need to study up for those questions. Additionally, some questions are absolutely harder or simpler if the interviewer is or is not a pure jerk and doesn't lead the interviewee on without any affirmation that they're on the right track. All points taken.


p>This was a very fun and engaging talk! I think we all learned something about each other. My personal favorite was the entire room's reaction to the adding things to an NSArray question: "You can't.", which, as the person with the slides, I said "Oh really, Junior Developer, you're telling me you can't add an element to this array?"

Thanks to all that attended! We'll meet again on 6/18.