John McDowall

(A demo app accompanying this post is available, with reusable parts easily extractable.) If you've ever written an iOS app, you'll know just how easy it is for your...

This is an updated version of a post I made in early 2013 that proved popular. This update reworks the solution from Objective-C to Swift 2.0. The code inline below is...

There's a couple of anti-patterns that I've noticed in my own code. Private methods are a code smell Private methods are not inherently bad, but they are a sign that you...

What is it? Bluetooth Low Energy (BLE) is a technology for allowing devices to communicate in a way that is highly optimized for conserving battery power. BLE devices...

Notifications and background downloading Prior to iOS 7, an inactive app is ignorant of notifications sent to the device. With iOS 7, an app can register to be woken when a...

There is now an updated version of this post that reworks the solution from Objective-C to Swift 2.0. A component of a project I am working on displays shop locations on a...

Here is the approach I took to performing the result of a method call, which is done in a reusable way which may be interesting. Instead of calling my method normally like...

Problem: You have a collection of objects.  Each object has a number of children.  You want all the children matching a criteria, AND the parent.  The child...

Often a developer will want to mirror the names of properties or methods of a class in some related dynamic resource that needs to bind to named members of the class. This...

There are several stages at which you can, and possibly should, validate data inputted to your application.  This post deals with server-side validation of user input before...