Category Archives: iPhone

App-o-Mat updates

I started App-o-Mat as an iOS tutorial site back when I was consulting. It mostly had cordova screencasts.  I’m going to be doing more writing about iOS there (native and possibly cordova-based).

You can subscribe to the mailing list there if you want to get updates. If you have requests for topics to write about, let me know.

Here are the latest posts:

How do I pass values from a VC back to the VC that presented it?

Ok, so you have a view controller that brings up another view controller. Let’s call the first one FirstVC and the second one SecondVC. FirstVC either presents SecondVC or there is some segue that it uses to bring it up.

How do you keep Storyboards from causing merge problems later?

There’s this myth in the iOS community that “professional” iOS developers never use Interface Builder. It’s meant to imply that coding your interfaces is always better, and if you don’t do it, you are somehow less of a programmer. The myth perpetuates the idea that IB is a crutch, a toy, something that only newbies use.

I call BS.

How do you pass values to a VC in a segue?

A theme I see a lot on StackOverflow is a developer makes a View Controller that collects some information from a user and wants to use it on a VC that they bring up in a segue.


Introducing 3D-o-Mat

3D-o-Mat is a simple app that creates the type of 3D photos that you view with red/cyan glasses.

I have been writing apps that do this for a while. It was one of the first things I wrote with DotImage back when I joined Atalasoft in 2006 and ported their image processing commands to WPF. Then, I wrote a simple version for iOS that I showed to middle-schoolers when I was a volunteer for DIGITS.

I was recently invited to speak at a Smith College Python programming summer program for HS girls and I decided to make this app more real.

PS: here’s a tweet sized version of the app in Python that I shared with the class the last time I spoke:

This gist shows a better way to do it that preserves the color in the original photos.

GamePlayKit Rule Systems on Smashing

I wrote a 2-part series on GamePlayKit’s Rule Systems framework for Smashing Magazine.

Part 1 is the basic idea and shows how to replace conditional logic that might be strewn around a project into a GamePlayKit rule-system.

In Part 2, I show the support for fuzzy logic rule-systems (logic values ranging from 0.0 to 1.0 instead of strictly true and false). It covers a little more of the features of rule-systems and how to implement NOT, OR, and AND for fuzzy values.

Both articles are supported by Swift Playgrounds in GitHub so that you can play with the concept and try different rules.

NerdSummit 2017 Talk: Introduction to iOS Development through Apps

On March 18th, I’ll be giving a presentation to teach iOS development by looking at completed apps and customizing them.

If you are planning to attend and want help after the talk to set up your machine and get started on the exercises, here’s what you’ll need:

  1. To do the exercises, you need a Mac with Xcode 8.2+ installed. If you don’t have access to a Mac, I think we’ll have enough people with one and can pair you with someone.
  2. We’re going to be forking apps on GitHub, so having a GitHub account already would be good.
  3. You don’t need a device — we’ll be able to use the simulator for all of the examples, but if you want help getting apps on devices, sign up for a free Apple Developer account.

It’s a beginner talk, so anybody with an interest in programming will get something out of it. It will help if you have some programming experience (in any language).

Here’s the plan

  1. Basic Swift (enough to be able to read the apps)
  2. The MVC pattern as implemented in UIKit
  3. Interface Builder (connecting outlets and actions)
  4. Then, we’ll fork an app and make some customizations
  5. Based on the group’s questions, we’ll cover as much iOS Development and Swift as we need.

The idea is that the apps we’ll fork are generally useful apps that people might want a custom version of. All of the code is open-source, and you’ll be able to continue to develop them after the workshop if you wish and release them to the App Store.

I’ll introduce the apps in subsequent blog posts here (I have to make them).

There will be handouts so you can work on your own after the talk.

Handling Pluralizations Correctly in Strings

Earlier this year, Trello launched in 21 languages. I worked on the i18n effort of the iOS apps, and I have been collecting thoughts for a series of blog posts. The first one, about plurals, was published today on the Trello Tech Blog. It begins

On page 52 of my copy of K&R, in a discussion of the ?: operator, is this line of code

printf("You have %d item%s.\n", n, n==1 ? "" : "s");

And thus began my decades-long proliferation of plural-unfriendly strings.

To see why, read the rest of Lessons from Internationalizing Trello, Part I: Plurals on iOS

As a follow-up, I found a Russian translation of K&R. Here is how that line of code is translated

printf("Вы имеете %d элемент%s.\n", n, (n%10==1 && n%100 ! = 11) ?
    " " : ((n%100 < 10 || n%100 > 20) && n%10 >= 2 && n%10 <= 4) ?
    "а" : "ов");

Which is another way to do it, I guess.

Habits 3.0

Back in 2008, I learned Objective-C to make my first “iPhone OS” app, Habits. When it was released, Habits looked like this:


This weekend I finally finished v3.0 and made it free.

As this is a developer site, the more interesting thing to note is that Habits was originally made in the first iPhone supporting version of Xcode (with external Interface Builder) and I have been migrating the project file from version to version since then (using 7.3.1 to make the current build).

Some things that were introduced into Habits for this version:

  1. Swift – all new classes were made in Swift and many existing ones were refactored into Swift
  2. Accessibility – Since NSSpain 2015, I’ve been running my iPhone with triple-Home to get into VoiceOver (suggested by Hermes Pique in this talk). Doing that made me realize (1) what it was like to use Habits without looking at it (2) how easy it was to make it work properly.
  3. fastlane – specifically “deliver” to manage the iTunes record and “frameit” for fancy screenshots
  4. Carthage – there had never been 3rd party libraries in Habits, but I decided that one was worth it this time.
  5. TOCropViewController – A simple framework that does one thing very well – provide a View Controller for cropping images. I use this instead of the built-in iOS one because it supports locked aspect-ratios.