Skip to main content

Optional types in Swift

At work, I code in either Java, Javascript (AngularJS, Node.js) or CSS via bootstrap, so when I am coding in Swift, it is strictly something I do in my free time. Hence I make a point to keep notes of stuff that I learn which can potentially serve as a future reference for me.

Swift (Apple's new programming language), allows for the presence optional type or optionals. This concept is very well explained in this Ray Wanderlich podcast, at time 27:03 (mins:secs). As mentioned in that podcast,  the designers of Swift decided to ensure that you have no null (nil) references in your code. So in languages such as Java, say you have an object called person which represents a person, that has information about where the person lives i.e. address property. There is some more detail in where the person lives i.e. the name of the street i.a. street property. So now if we want to what street the person lives on, you would do person.address.street. That way you trust the property address to never be null, by just calling person.addres.street. However there are instances when it does make sense for a certain property to be null and that is why optional types exist in Swift. So nullable (nillable) behaviour is something that you opt into. As pointed out in the podcast this is a very good safety feature.

References

This stackoverflow post has a very good answer with examples on the use of optional values in Swift.

The official documentation is also a good place to read about how to use
Labels:

Comments

Post a Comment

Popular posts from this blog

Upload to AWS S3 from Java API

In this post, you will see code samples for how to upload a file to AWS S3 bucket from a Java Spring Boot app. The code you will see here is from one of my open-source repositories on Github, called document-sharing. Problem Let’s say you are building a document sharing app where you allow your users to upload the file to a public cloud solution. Now, let’s say you are building the API for your app with Spring Boot and you are using AWS S3 as your public cloud solution. How would you do that? This blog post contains the code that can help you achieve that. Read more below,  Upload to AWS S3 bucket from Java Spring Boot app - My Day To-Do (mydaytodo.com)
Post a Comment
Read more

Addressing app review rejections for auto-renewing subscription in-app purchase (iOS)

The ability to know what the weather is like while planning your day is a feature of  My Day To-Do  Pro and as of the last update it’s also a part of the  Lite version . Unlike the Pro version it’s an auto-renewing subscription based  in-app purchase (IAP)  in the Lite version. What means is that when a user purchases it, the user only pays for the subscription duration after which the user will be automatically charged for the next period. Adding an  auto-renewing  subscription based IAP proved to be somewhat challenging in terms of the app store review i.e. the app update was rejected by the App Review team thrice because of missing information about the IAP. Therefore in this post I will share my experiences and knowledge of adding auto-renewing IAP in hopes to save someone else the time that I had to spend on this problem. In-App purchase This year I started adding IAPs to My Day To-Do Lite which lead to learning about different types of IAP...
1 comment
Read more

App update, discovering Protractor(testing) and an Angularjs State machine

So for the last couple of weeks, I have not be able to update my blog or finish a couple of the posts that I started writing. Well, I have...been a bit busy, with some the following things,  Testing my app I have been using the app( iOS ) on my iPhone for the past couple of months now, which is both good and bad. The good thing is I can test it and the bad thing is, I can use it every day. Part of the reason, I started building this app is to have something that I can and like to use everyday and since I am already using it, the incentive to release it is not as high as if it were something that I could not use. Anyway I did make some good progress over the last couple of weeks, like  Delete the app from my iPhone and do a clean install: this did help me find a few simple bugs that would pop-up when the app is first installed GET AN APP ICON, FINALLY! this was a bit of a hurdle and I thanks to Fiverr  and fivercrazyguy , I finally have my app icon. The day job ...
Post a Comment
Read more