Pro Tip: Boolean chaining

You might occasionally reach a state where a status is defined by a sequence of boolean values. This is common occurrence when dealing with state machines, here’s an abstracted example:

var isConnected : Bool = true
var hasData : Bool = true
var isDataStale: Bool = false

var isDataReadyForPresentation : Bool {
  return isConnected && hasData && !isDataStale

Depending on the complexity of your state machine, the definition of the variable ‘isDataReadyForPresentation‘ would be sufficient, but if calculating this value depends on a sequence of  a large number of values, you quickly will loose readability on a long line of boolean conditions.

Continue reading “Pro Tip: Boolean chaining”

Managing user input

When dealing with user input, Murphy’s Law will always apply in full force: “Anything than can go wrong will go wrong”. Or as Douglas Adams would have it:

“A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools”

This is a common crux for us developers: how do we architect a completely foolproof system? There are many routes you can take to do this, but in this particular blog post, I would like to focus on a specific aspect of this: managing user inputs.

Continue reading “Managing user input”


I find it hard to believe that any developer can deny the importance and usefulness that a right use of hashes can offer their applications.

From security and data management to object comparisons, hashes are used extensively throughout the framework and should, in the right circumstances, be used by you as a developer when the time merits them. But, what exactly is a hash? Simply speaking it’s a form of encryption that maps data of arbitrary length to a data object of a fixed size (number, string, etc),  but if you want to get all technical you can read this article on Wikipedia, wherein it explains hashes and it’s use through hash functions:

Continue reading “Hashing”

Automating keyboard layouts

Normally, developing a keyboard interface starts with putting a UITextField, a UITextField, or another UIResponder into your application’s view hierarchy…

And then this component becomes a statement: “From here forth, I declare this view to be a keyboard input view”. Except… Well… it isn’t, or at least doesn’t act like it. Unless you manage the layout of your content by implementing your keyboard notifications, the app’s main view will not respond or adapt to the keyboard update, and all sort of messed up situations can arise from this, like the keyboard overlaying your UITextField, UIScrollViews not being able to scroll or UITableViews not being able to display their last rows of content.

Continue reading “Automating keyboard layouts”