Tag Archives: ios

Brain, refactored

For a long time I was too busy to learn anything much new, while running a company and caring for two small children. But more recently, I had the time to catch up on some technical knowledge and I remembered how much I love pure learning.

This post seems to be a big list of what I’ve learned over the last couple of years. Actually, I meant to write it a year ago, so now it’s also a list of what I need to revise.


I caught up with the C++ renaissance by reading Effective Modern C++. and watching heaps of CppCon, C++Now, and Meeting C++ conference videos, such as CppCon 2014: Herb Sutter’s Back to the Basics: Essentials of Modern C++ Style, (the one with almost always auto).

I exercised my growing knowledge of modern C++ by first using some modern C++ in gtkmm and Glom, and then doing a massive rewrite of libsigc++. I also explored some modern C++ generic programming techniques with tuples and dynamic programming.

Along the way I experimented, in Glom’s code, with some of the ideas from Sean Parent’s talks, such as the “no naked for loops” idea from his “C++ Seasoning” talk from Going Native 2013.

I read the old Boost Graph Library (BGL) book, to tie C++ and graph theory together in my head. I spent lots of time, off and on, trying to clean the BGL code up, and modernize it, but it’s a struggle and I’ve only managed to get some simple stuff accepted so far.

The BGL book is ancient but its ideas about C++ concepts are only just about to become mainstream, hopefully in C++20. I also read Alexander Stepanov’s  wonderful From Mathematics to Generic Programming book, which convinced me even more.

I tried to get a simple explicit operator bool check into clang-tidy itself, but that didn’t get far and I chose not to be a pain by being pushy about such an unimportant contribution.

I started to learn about some compiler theory by writing some actual code.

I listened to the complete backlog of CppCast podcast episodes and I now listen to every episode as soon as its published.

Java and Android

I revised and updated my Java skills by reading Effective Java Programming and Programming Android. I regularly listened to the Fragmented and Android Backstage podcasts, but not so much recently. I gained some real-world Android programming experience by creating the Android app for Galaxy Zoo after first trying to create an Android app for my Glom database system. The Galaxy Zoo app was quite popular, but sadly, it’s not working right now – I need to find time to adapt it to their changed  backend API.

Java and web

I spent some time with Java as a way to work on backend (distributed) systems, reading the JAX-RS book, the,Spring Microservices in action book, and the Spring in Action book.

I gained some more Java/GWT/AppEngine (and Resty-GWT) experience by creating the Big-O Quiz website. I  used bigoquiz.com to take organized notes about the computer science that I learned subsequently. It asks me questions to remind me. But see below about me rewriting bigoquiz.com with Go and Angular.

iOS / Objective-C

I learned iOS (iPhone/iPad) programming by watching all 18 lectures in Stanford’s “Developing iOS 7 Apps for iPhone and iPad” course and then creating the iOS app for Galaxy Zoo. I used Objective-C, but now I have a reason to learn Swift.

Like the Android app, this is currently broken, because the backend server now has a very different API.


I learned Go via the The Go Programming Language book, taking extensive notes from the perspective of a C++ developer. To gain initial experience, I rewrote bigoquiz.com‘s backend with Go, instead of Java, and found the resulting code refreshingly simple.

I now use Go regularly at work for backend microservices and I’m quite content with it. For larger projects I’d still prefer C++, but not all projects need to be large.


I finally gave up on GWT, long after everyone else realised that it’s barely maintained. So I took the opportunity to rewrite the bigoquiz.com frontend in Angular, using Typescript. Learning it was easy with the excellent Angular tutorial.

I’ve since tried out React too.


I read the huge Programming in Scala book, because I use Scala on a large project at work. I’m fond of it, but I think its simplest ideas should just be in Java, and the cleverest stuff tends to make code hard to read.

Algorithms and Data Structures

I grew to love computer science by doing Coursera’s/Stanford’s “Algorithms: Design and Analysis” course, part 1 and part 2 by Tim Roughgarden. I then read Cracking The Coding InterviewThe Algorithm Design Manual, Algorithms, by Robert Sedgewick, and the first half of the CLRS Introduction to Algorithms book. I worked through the first few lectures of Tim Roughgarden’s “A second course in Algorithms” to cover max-flow and min-cost matching algorithms.

I went through the material 2 or 3 times, from various perspectives, eventually making sure to actually implement each data structure and algorithm.

I also read Jon Bentley’s Programming Pearls book, for some practical advice.

I watched, and re-watched, far too many of Tushar Roy’s algorithm walkthrough videos.


I already have years of Linux development experience, but I knew I was missing out on some knowledge and habits. So I solidified my Linux knowledge by reading Linux System Programming. (And now, later, I think I should read it again, though I wish there was a newer edition.)

I’m still looking for a really good book about bash scripting and general command line cleverness.

Distributed Systems

I didn’t have practical experience with at-scale server-based systems but I became acquainted with the ideas by reading Google’s Site Reliability Engineering book.

I discovered it later, but Tim Berglund’s 4-hour Distributed Systems in One Lesson series of videos  is an excellent and engaging overview of the main themes. If it’s no longer available on YouTube but I think it’s so good that you should buy it.

Mikito Takada’s free Distributed Systems For Fun and Profit book is also an excellent introduction and overview.

I also listened to many old episodes of the Software Engineering Radio podcast and the Software Engineering Daily podcast, which often cover similar topics.


Even as a regular C and C++ coder, I realized how little I thought about the computer architecture that my code is running on. Various talks by Andrei Alexandrescu and Chandler Carruth really opened my eyes to these performance considerations that seem more relevant in at-scale server code than they were in typical desktop applications or even in embedded code.

For instance, Andrei Alexandrescu’s Code Dive 2015 “Writing Fast Code: part 1” and part 2 talks, as well as his “Optimization Tips – Mo’ Hustle Mo’ Problems” talk at CppCon 2014 and his “Writing Quick Code in C++, Quickly” talk from Going Native 2013.

For instance, Chandler Carruth’s “Understanding Compiler Optimization” talk from Meeting C++ 2015, his “Tuning C++: Benchmarks, and CPUs and Compilers! Oh My!” talk from CppCon 2015, his “Efficiency with Algorithms, Performance with Data Structures” talk from CppCon 2014, and his “Care and Feeding of C++’s Dragons” talk from Going Native 2013. Also his more recent “High Performance Code 201: Hybid Data Structures” from CppCon 2016.

Mike Acton’s famous “Data-Oriented Design and C++” talk, from CppCon 2014, really gets to the point about this too, from more of a C perspective.

Coding Habits

I finally took the time to learn Vim enough to use it as my daily editor, after reading Practical Vim. I also learned to use screen and Tux but I haven’t incorporated either into my daily habits.

Ironically I never found my Linux environment outside of the terminal to be as keyboard friendly as the old pre-X MacOS. So staying in the terminal helped me to keep my hands off the mouse again. I practiced with the Klavaro typing tutor to get some of my good habits back.

I worked through the first 25 tasks from Project Euler and most of the tasks from HackerRank. I spent two intensive months working through every task on InterviewBit (around 260 at the time).

I highly recommend InterviewBit – they have a vast set of coding problems, nicely organised, with helpful test cases and tips for when you get stuck, so you can actually improve. HackerRank is useful too, but it feels less directed and the need to parse stdin input for every task gets annoying.

Along the way, I took a note of each C++ typo or generic algorithm mistake that I made, and started counting how many times I made each mistake, so I could focus on breaking my worst habits.


I read some books about project and people management too, revising agile processes with the Scrum and XP from the Trenches and Kanban and Scrum: Making the most of both free ebooks.

The Manager’s Path maps out the various roles that are popular at software companies today, with suggestions about regular actions that each might perform, but it doesn’t seem useful beyond establishing that common language, and I hope it becomes outdated.

I recently read Measure What Matters, and Radical Focus, about OKRs, and I’m very enthusiastic so far. I like the idea of openness and regularity in businesses, to allow focus and alignment, almost like well-functioning decentralized open source projects that I’ve known.

I also got interested in product management, but I haven’t taken it far yet. The Cracking the Product Manager Interview book was rather superficial. I hope to dig deeper into this topic in future.


I revised my Design Patterns knowledge by reading Head First Design Patterns and I used it to build a Design Patterns quiz.

I learned the Lua programming language and the Moai game-development platform via the Programming in Lua book and the “Developing Mobile Games with Moai SDK” book. This was for an idea I’d had for a kids’ programming app that didn’t seem quite worth the effort in the end.

I learned a bit about Hadoop by reading the “definitive guide” book, but I never got around to using it.

Galaxy Zoo iPhone/iPad app

A few weeks ago I finally released my iOS app for Galaxy Zoo on the Apple App Store. Now that it’s been used a bit and I’ve had the chance to fix a couple of crashes, I’m announcing it properly. I am a little afraid of harsh reviews but please try it out and  be kind.

I’m still not quite as comfortable with it as I am with my Android app for Galaxy Zoo, partly because I just don’t feel at home with Objective-C and because iOS lacks something like SyncProvider. But it seems to work.

I actually finished writing the app about eight months ago, but I had to wait until Apple gave me permission to use the old “Galaxy Zoo” app name, allowing this app to appear as just a new version of the old (withdrawn) Galaxy Zoo app from 2014 or so. Joe Zuntz, who wrote the old app, was very helpful with that, pestering Apple until it happened. Unlike that old app, it should be possible to keep this one working even if the server changes, because it’s open source on github.

Here are some screenshots:


Galaxy Zoo app for iPhone: Learning iOS Development

My Android app for Galaxy Zoo is doing pretty well. Creating it gave me a chance to learn Android development quite thoroughly. So I thought I’d do the same for iOS, with Objective-C. The Galaxy Zoo iPhone app is now mostly done, though it’s only available via TestFlight for now. Please send me your Apple ID (usually your email address) if you’d like to try it.

Over the years, I didn’t much believe the reports of Apple’s APIs, tools, and documentation being so wonderful. But I had hoped things would be better.  Android’s API and documentation can be frustrating, but developing for iOS feels worse, with rather primitive tools. It’s still doable, but I can’t think of anything about it that I prefer to Android development.

This is a rough collection of rants, so I reserve the right to revise my opinion when I have gained more complete understanding.


Learning Objective-C was not too difficult, though I still find its syntax and terminology arbitrarily different and often obstructive. Watching all of Stanford’s “Developing iOS 7 Apps for iPhone and iPad” course (on iTunes here too) helped me gradually get used to Objective C, XCode, and Apple’s *Kit APIs.

I chose to start with Objective-C rather than Swift, just so I’d have a chance to learn it and to avoid any problems caused by Swift still being fairly new. I plan to convert my code to Swift soon as its gradually becoming the default language for iOS development. Unfortunately it looks like Swift inherits most of Objective-C’s weird features.

Whereas in Java or C++, you would call a method on an instance like this:

SomeResult *someresult = something.somemethod(arg1, arg2);

in Objective-C, you’d send a message (not call a method) to an instance, like this:

SomeResult *someresult = [something somemethod:arg1 witharg2:arg2];

And if something is nil (null) then, unlike C++ or Java, there will be no runtime crash or exception – you’ll just get a null result. So you don’t need to check for nulls unless you really need the method to be called, though this leads to all kinds of extra implicit paths through your code. I secretly like this, but it is of course madness.

Users of C++ or Java will also be shocked at how it’s normal in Objective-C to add API to already-defined classes instead of providing the API via derived classes or helper methods. For instance, when using the (not from Apple) AFNetworking library, you can #import “UIImageView+AFNetworking.h” to add methods (messages) such as setImageWithURLRequest to the regular UIImageView class.


XCode is overly simple when it comes to basic code editing and debugging. I was amazed that I couldn’t just click on an exception’s backtrace to go to the relevant line of code. And I really missed the refactoring features in Android Studio or Eclipse.

XCode is not intuitive, forcing you to learn where to click and when, instead of learning how some structured code works. For instance, you need to know about the magic Ctrl-drag to access UI controls in your code, to respond to UI events from those UI controls.  Embedding your views into tab bars and navigation views is similarly obscure.

Auto Layout

Nothing has frustrated me more than Auto Layout in iOS. Amazingly, iOS had no real automatic layout until iOS 6 in 2012, and I don’t think it was really usable until iOS 7 in 2013. And developers still needed separate layouts (Storyboards) for iPhone and iPad versions of their apps until iOS 8 in 2014.

Auto layout seems to be a matter of playing with:

  • Constraints: You can add constraints, for instance to say that a child view (widget, control) should be the same width as another view , or that it should have a certain size of margin between itself and the leading (left) edge of its container. The XCode UI makes it really hard to see what constraints exist and the XML is obfuscated, so this is really difficult. You still need to specify positions and width/height for all your views, even if they would be changed by the auto layout, so you inevitably have to keep dealing with XCode’s warnings about the “frame” not being the same as it would be at runtime.
  • Content Hugging (vertical or horizontal): A high value stops the view from being made larger, instead “hugging” its content (such as text). I dislike this terminology particularly.
  • Compression Resistance (vertical or horizontal): A high value stops the view from being made smaller.

Content hugging and compression resistance are numeric values, so your layout tends to become littered with arbitrary values such as 100, 250, or 1000, as you try to make things work, with very little sense of overview of the whole layout.

I much prefer the automatic layout systems used in GTK+ and Android, where it’s mostly just a matter of using parent layout containers and telling them how to arrange their children. Android’s layout system is often cryptic, compared to GTK+’s simplicity, but the layout XML is readable so it’s fairly easy to try things out. Stackoverflow answers about iOS autolayout are all about where you should click in various versions of XCode, but the answers about Android layouts can just show XML samples.

Android child fragments can be difficult, but I eventually worked things out. In iOS/XCode still don’t have a satisfactory way to auto layout child containers that contain child views.


CoreData seems to be a way to access a SQL-like database using generated classes. For instance. I find the manual code generation quite awkward, but I suppose it works. Most of my difficulties were to do with using CoreData with RestKit. But I eventually found its saveToPersistentStore() method to actually store the data reliably.

I’ve also missed having an equivalent for Android’s SyncAdapter, though I have not yet found the same UI performance problems that made it so necessary on Android.

Beta testing

I can understand Apple’s insistence on reviewing all app uploads to their app store. But it’s annoying that every version of private beta tests have to be approved too.And

To let someone beta test your app via TestFlight, you need to know their Apple ID and add it manually in the iTunes Connect website. In comparison, with Google’s Open Beta Testing for Android, you can just publish a URL that lets people opt in themselves.

And as far as I can tell, users don’t get any notification when you release a new beta version. So your old testers generally don’t even install the new version until you’ve bugged them individually to do so.