This post covers how to use the Grand Central Dispatch's DispatchGroup object to coordinate separate web requests so that UI updates can be completed at the same time, even when asynchronous requests aren't guaranteed to return in a predictable order. This post is primarily a tutorial of using GCD's DispatchGroup, and …

Read More

This post is a cheat sheet for sorting sequences of custom objects using Swift's sort operators. While sorting simple types (String, Int) are covered well in Apple's documentation on the subject and in many other places, I've focused below on sorting custom object types, which is more relevant to my daily work. The …

Read More

What is Map? Map is a term that has roots in other technologies (such as Hadoop big data processing, which is where I've used it before 🙂). Map means to iterate over a sequence of objects, and perform some operation on each one, returning a new sequence of objects as the final output. The operation performed is …

Read More

What is Reduce? Map is a general term that has roots in other technologies (such as Hadoop big data processing, which is where I've used it before 🙂). Reduce means to iterate over a sequence of objects, and perform some operation on each one, returning some summary value computed from the entire set. Map and Reduce are …

Read More

This technique demonstrates the simple but useful task of capturing the contents of a UIView as a JPEG image data object. The resulting Data object can be written to a .jpg file, uploaded to a web service, or sent as an e-mail attachment (as is covered in this related post). Application This technique is relatively …

Read More

Sending content from an iOS application to external sources like email is a common requirement. This quick post summarizes the steps to implement this feature. Aa an added twist, the project used for this technique post includes capturing an image from one of the app's UIViews. Below is a video demo of the application …

Read More

This techique illustrates a mid-level technique: impelmenting custom Core Graphics drawing in a UIView. Often a custom effect in a View can be implemented by adding subviews and positioning them with constraints. But other times, you just need to take over and draw what you need. In those cases--CoreGraphics to the …

Read More

The most common approach to displaying images in an iOS application is to include images in asset catalogs compiled into and shipped with the app. For images that are provided at design time and never change, this is nearly always the best approach. There are some scenarios where bundling images isn't possible or …

Read More