Hire iOS Developer Freelancer

Simple interview questions most candidates struggle with.
Over the years we have seen the rapid growth of mobile app users. These apps have fundamentally changed the way we live our lives – from the way we communicate with people across the globe, to the way we carry out banking transactions in our homes. As a result, a lot of companies are now working to create mobile apps for their brands in order to reach a wider range of audience.

Knowledge of the latest mobile trends

With a great deal of iOS changes occurring in a year, it is greatly significant that the mobile engineer you hire is up-to-date and has the precise knowledge of the latest iOS features. It would be a waste of resources if your developers created an app that is no longer compatible with the latest version of the software.

Bonus points if your mobile developer has quick learning skills. Since there is no slowing down in rollouts of software updates, it is always great to have someone in your team who can swiftly acquire an understanding of the new features and apply the necessary updates in mobile codes.

Some of the Recent changes on iOS

Apple releases annually a major software update containing fixes for their iOS and some cool new features for their customers to enjoy. But aside from the updates announced during Apple’s event launch, the company also releases minor software changes to keep their devices running smoothly.

Since iOS is constantly developing its mobile operating system, recent times brought us some really satisfying features and improvements. Here are key changes in recent iOS:

  1. Dark mode – giving apps beautiful dark color, saving energy, easier on eyes and allowing for scheduling for maximum satisfaction
  2. Contacts API – hundreds of new, more specific relationship labels in Contacts help users manage their growing contact lists.
  3. Login with Apple – sign in to apps and websites quickly and easily using the Apple ID you already have.
  4. Maps – the brand-new map features significantly improved and more realistic details, with the possibility of exploring where you are going before you get there
  5. Reminders – the redesigned Reminders app features more powerful and intelligent ways to create, organize, and keep track of your reminders.
  6. Keyboard – allowing you to write messages by swiping your finger without removing finger from keyboard
  7. Accessibility – introducing new ways to control your phone entirely with voice
  8. CarPlay – giving you a single place to keep track of maps, audio controls, and smart
  9. Siri suggestions
  10. Photos – allowing you to browse your photo library with different levels of curation, photos are intelligently organized, the editing is easier than ever
  11. Privacy and Security – letting you totally control your location data, so that no application would be granted access to your location unless you allow it, same goes with wifi and Bluetooth connections
  12. Siri – the voice is now 100 % generated by software making it sound more natural while speaking longer phrases
  13. Memoji and messages – grants you an automatically created set of emoji expressions accessible right from the keyboard in iMessage or any other app
  14. AirPods – you can now connect two iPhones and share the audio on both devices

Strong problem-solving skills

Mobile development has an impression of being less complicated than backend. However, when problems arise, it does not really matter which one is easier to develop—what counts is how quickly your developer is able to fix the issues. Check the applicant: Do they have strong problem-solving skills? Can they provide quick solutions to bug fixes? In a business where every time spent is critical, having a developer with powerful problem-solving skills and the brainpower for such technicalities can help make or break your projects.

Communication and Organizational Skills

In almost any business, it is constantly essential to have employees with good communication and organizational skills. This makes it easier to work on projects since instructions are understood well, concerns are raised clearly, and tasks are handled in an orderly manner. For iOS developers, this is more significant since the work they do is more on the technical side which can easily be mistranslated or misunderstood by people with no technical knowledge.

Previous work experience

Hiring someone with previous work experience is always helpful and beneficial for companies. Not only does it give you an idea of an employee’s capabilities, but as well it reduces the learning curve since they already know the demands of the job. Perhaps, the more important question that you should be asking in terms of work experience is where they had worked previously. Have they worked in an international environment before? Do they have work experience with fast-paced US-based startups? How about remote works done previously? Since your company might get clients from all over the world, it can help if you have a mobile developer who has knowledge of how to deal with people and projects from international environment.

Awareness and knowledge of security aspects

Living in the digital age can pose a lot of security issues for customers and business owners. That is the reason why data privacy and security should be a top priority for anyone who is dealing with tech sites and applications. For your software engineers and developers, make sure that they are fully aware and knowledgeable of the security policies to avoid any issues in the future.

Check for computer science foundations

Knowledge in the area of computer science is not always necessary when applying for a mobile engineer post. In fact, a foundation in this topic is oftentimes missing for a lot of mobile engineers. However, if you want someone who can complete tasks more smoothly or have a superior understanding of the projects they are dealing with, it is better to get a developer with the said background.

Passion for the job

What are the things that drive and motivate your mobile engineer to work in this field? Some companies would no longer ask this question during the hiring process since they only focus on the technicalities and skill sets of applicants tested during the earlier stages. However, it is valuable to know earlier on if your developer is passionate about the job, since people who actually enjoy what they are doing, tend to be more productive and efficient at work.
With a lot of iOS changes happening in a year, it is very important that the mobile engineer you hire is updated and has the right knowledge with the latest iOS features.

Clear understanding of programming language

Finally, it is really substantial to have experienced developers on the team. Yet the real challenge in the hiring process is evaluating the knowledge of the applicant. One solution is to check his understanding of the tools, in this case, the programming language that he uses. So how would you do it? By asking pretty hard iOS questions during the interview. 

Here are some exemplary questions you can use:

1. What will happen, and why, when we execute main.sync on the main thread?

DispatchQueue.main.sync { }

Sync will block the thread from which it is called and not the queue on which it is called. It is the property of DispatchQueue which decides whether the DispatchQueue will wait for the task execution (serial queue) or can run the next task before the current task gets finished (concurrent queue).

2. What is didSet or willSet for a variable and what happens when we assign a value to a variable during initialization?

The willSet and didSet observers of superclass properties are called when a property is set in a subclass initializer, after the superclass initializer has been called.
They are not called while a class is setting its own properties, before the superclass initializer has been called.
willSet is called just before the value is stored and didSet is called immediately after the new value is stored.
willSet and didSet observers are not called when a property is first initialized.
They are only called when the property’s value is set outside of an initialization context but you can create an own set-Method and use it within your init-Method:

3. When do you use unowned and when weak in Swift closures?

Use a weak reference whenever it is valid for that reference to become nil at some point during its lifetime. Conversely, use an unowned reference when you know that the reference will never be nil once it has been set during initialization.

4. What are the differences between setNeedsLayout, layoutIfNeeded and layoutSubviews()?

The method setNeedsLayout for a UIView tells the system that you want it to layout and redraw that view and all of its subviews when it is time for the update cycle. This is an asynchronous activity because the method completes and returns immediately, but it is not until some later time that the layout and redraw actually happens, and you do not know when that update cycle will be.

The method layoutIfNeeded is a synchronous call that tells the system you want a layout and redraw of a view and its subviews, and you want it done immediately without waiting for the update cycle. When the call to this method is complete, the layout has already been adjusted and drawn based on all changes that had been noted prior to the method call.

The default implementation of this layoutSubviews does nothing on iOS 5.1 and earlier. Otherwise, the default implementation uses any constraints you have set to determine the size and position of any subviews. Subclasses can override this method as needed to perform a more precise layout of their subviews.

Native iOS Swift vs Google Flutter or React Native - the modern approach

Swift, Google Flutter and React Native are among ones of the most popular technologies for mobile app development. One may ask which one to choose for the project and the answer is pretty simple—it depends on their needs.

The approach

There are two leading approaches to developing mobile apps: Native and Cross-Platform. The first one is represented by Swift and it stands for developing the app exclusively for a specific platform (iOS in this specific case) with all its features. On the other side, there are Google Flutter and React Native representing the cross-platform approach where, as their names state, the app can be run on different platforms. So without hesitation let us dive right into details.

Development time

It turns out that cross-platform technologies tend to have lower time-to-market. Not only do they come with better code reusability, but also provide hot reloading keeping the app running at the time files are edited at runtime.

Potential users

Naturally using native iOS swift limits the user pool, as the same app written in React Native or Google Flutter could potentially target up to 50% more potential users. There is no other option to match it but simultaneously developing the app for Android.

Performance

Taking into consideration both CPU and Memory usage, Swift tends to have its edge. Performance tests proved that it uses CPU better than Cross-Platform technologies while consuming less memory, although it is not such a big deal.

Cost

Due to the shorter development cycle React Native and Google Flutter become obviously more cost-efficient. In addition to this, they are relatively easier to learn and debug, making the training part more clear for companies.

Stability

Naturally, Swift being a native language for iOS has advantages in terms of native modules and Apple support making it less likely to crash in cases of technology changes. Swift, Google Flutter and React Native are all very powerful solutions for app development that are being constantly developed to ensure the users can get the best quality products possible. That gives us sufficient certainty that choosing any of these technologies will provide appropriate tools to build great apps. Eventually, the choice of one over another should be based on the project requirements. As mentioned, one of the platforms where mobile apps are created is Apple’s device iOS. If you are one of the companies looking to create an app for iOS, it is important to have a mobile engineer with a set of expertise in this operating system in order to have a smooth and successful app development process.
It is good to know earlier on if your developer is passionate about the job since people who actually enjoy what they are doing tend to be more productive and efficient at work.
The method setNeedsLayout for a UIView tells the system that you want it to layout and redraw that view and all of its subviews when it is time for the update cycle. This is an asynchronous activity because the method completes and returns immediately, but it is not until some later time that the layout and redraw actually happens, and you do not know when that update cycle will be.

The method layoutIfNeeded is a synchronous call that tells the system you want a layout and redraw of a view and its subviews, and you want it done immediately without waiting for the update cycle. When the call to this method is complete, the layout has already been adjusted and drawn based on all changes that had been noted prior to the method call.

The default implementation of this layoutSubviews does nothing on iOS 5.1 and earlier. Otherwise, the default implementation uses any constraints you have set to determine the size and position of any subviews. Subclasses can override this method as needed to perform a more precise layout of their subviews.

Take away

There are a lot more traits out there that you can look for when hiring iOS mobile engineers. But in general, it is best to check if they have knowledge and passion for mobile. Check out the blog of DevsData—a software development company focused on mobile apps – for more hiring tips for web, mobile, back-end and Big Data.

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Acknowledgements

Unbeatable tech experience

“I interviewed about a dozen different firms. DevsData LLC is truly exceptional – their backend developers are some of the best I’ve ever worked with. I’ve worked with a lot of very well-qualified developers, locally in San Francisco, and remotely, so that is not a compliment I offer lightly. Their depth of knowledge and their ability to get things done quickly.
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Nicholas Johnson

MENTOR AT YC, CEO OF ORANGE CHARGER LLC

Acknowledgements

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