You’ve been working on your billion dollar app
IBOutlet and IBAction connections look like they’ve been disconnected (see image below):
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Month: January 2018
Writing expressive, meaningful, and readable code in Swift 4
Let’s talk about creating understandable and maintainable code in Swift 4, code that can be easily read by other programmers, can be readily debugged, can be reused, and can be enhanced and extended in the future. We’re going to limit today’s discussion to: 1) how best to come up with good names for functions and how best to name their arguments, parameters, and argument labels, and 2) how to use meaningful and descriptive variable (var) names — and constant (let) and enumeration (enum) names, etc. The goal is to create code that reads as to close to English as possible.
You may believe that this topic is overly simplistic or pedantic, but sometimes it’s the “little things” in life that really matter — especially when you have applications that are made up of millions of lines of code, made up of “little things” like function definitions and function calls.
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Xcode tidbits: Open as Hex, Open As Source Code, (Git) line endings, and text encoding
With this article, I’m starting a series about all the goodies — useful tools — that can be found in Xcode. Some of these tidbits are tools everyone knows about while others are barely documented to undocumented. For example, how many of you know that you can view, inspect, and debug all your Auto Layout constraints live during app execution using the “Debug View Hierarchy” Xcode feature? I discussed that feature in detail in this article, “Troubleshooting Auto Layout using Xcode’s Debug View Hierarchy.” Today, we’ll discover two editors that ship with Xcode, the “Open As > Hex” and “Open As > Source Code” editors, both only available by right-clicking on files in the “Project Navigator” to reveal a contextual menu.
Understanding Swift 4 protocols and using them in your apps
NOTE: Learn all about protocol-oriented programming in Swift here, here, and here.
[Download two Xcode 9 playgrounds with full Swift 4 source from GitHub.]
We’re going to talk about “protocols” in the Swift 4 language today. I’ll explain them conceptually, and then we’ll start coding protocols with a simple example. We’ll then create our own versions of the Apple built-in Equatable and Comparable protocols, and apply them to two real-world classes, one for tracking financial securities and one for representing geometric lines/vectors. Finally, we’ll test our geometric “Line” class in a type of Swift playground that supports rendering user interface components (like UIView) live in the simulator. But first, please ponder the layman’s definition of the word “protocol” before moving on:
… The official procedure or system of rules governing affairs of state or diplomatic occasions. …
The accepted or established code of procedure or behaviour in any group, organization, or situation. …
A procedure for carrying out a scientific experiment…
Swift Protocols
Apple’s “The Swift Programming Language (Swift 4.0.3)” documentation states:
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Building Swift 4 frameworks and including them in your apps (Xcode 9)
- [Download Xcode 9 framework project with full Swift 4 source from GitHub.]
- [Download Xcode 9 framework CONSUMER project with full Swift 4 source from GitHub.]
Let’s talk about Swift 4 frameworks, one method for packaging, reusing, and sharing code. We’ll build our own framework and then include it in our own app. We could’ve talked about static libraries, but frameworks offer more advanced features — and will let us expand on code maintainability options in future discussions. (If you want to have that static versus dynamic library discussion, read this excellent article, but we won’t be debating the topic herein.) From Apple (my emphasis added):
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Understanding Swift 4 generics and applying them in your code
The original article – Swift 4 Generics – was published on appcoda.com.
Question 1: Can I write one Swift function that can find the index/position of any specific instance of any type stored in any array that stores objects of that type? Question 2: Can I write one Swift function that can determine if any specific instance of any type exists in any array that stores objects of that type? When I say “any type,” I mean including custom types (like classes) that I define myself. NOTE: Yes, I know that I could use the Swift Array type’s built-in functions, index and contains, but I’ll be using simple example code today to illustrate some points about Swift generics.
Continue reading “Understanding Swift 4 generics and applying them in your code”