If only there was a... button that you could just press to convert your app to Android or iOS, right? Or if only a quick and easy recompilation process had been enough. Or if the “Let's just make it look similar” approach was your “winning card”... There is no such thing as “easier way” to port an Android app to iOS and vice versa.

Instead, there are essential aspects to consider and to adjust your whole app porting process to, meant to stir you in the right direction:
 

• navigation
• design considerations/UX
• screen size and resolution 
• code and essential app architecture differences
• 3rd party services, frameworks, extensions, and used libraries 
   

And, as you might just guess, the list is incomplete. For it includes other factors, as well, such as device support, customer and business model considerations and so on...

To keep your app's architecture intact, while porting your app between Android and iOS — 2 platforms with drastically different UIs and core structures — considering the above-mentioned 5 factors becomes crucial.

Therefore, let's detail them, shall we?
 

But What Does App Porting Actually Mean? Its 4 Key Stages 

Let's start with some sort of definition of the whole process:

By porting your mobile app you're changing or rewriting its code so that it should work on a different mobile OS than the one that it's been initially developed for.

Clear enough?

“How long does it take to port an Android app to iOS and vice versa?” you might ask yourself.

Usually from 1 to 6 months, but it depends greatly:
 

• on your app's complexity
• on its core architecture
• on the entire ecosystem of libraries that it uses, on its design particularities
• on the business logic behind
   

Speaking of which, analyzing precisely the driving business logic is as critical as it is underrated by developers who usually stick to: adapting a platform and eventually writing the needed extra code.

“And what are the essential steps to take to porting my app?”

Glad you asked. Here are the main stages that an effective mobile app porting process should include:
 

1. analysis and plan
2. technical assessment
3. the porting itself
4. intensive QA 
    

1st Factor to Consider When You Port an Android App to iOS: Navigation 

Navigation is the factor that "miles" sets apart the user behavior on Android phone from the user behavior on iPhones. 

Here's why:
 

• Android devices are equipped with 3 different buttons: Home, Back and Multitasking button
• iPhones only have the home button 
   

Now, imagine tapping a multitasking button as in the Android platform: you can't get away with a simple transfer to iOS. Instead, you'll need to write the proper code for it from scratch.

And there's more to navigation and to the way that it is drastically different from one platform to the other. For instance: 

Both horizontally and vertically displayed elements on iOS vs vertical elements only, on Android devices.

Tip: if you wish your iOS app to look similar to its Android alternative, there's always the handy compromise that you can make of placing in-app tabs in the bottom of the screen.
 

2nd Factor to Consider: Design Considerations/UX

You'll have to reconstruct your app's user interface from scratch to convert it from Android to iOS (or the other way around)!

Face it, deal with it and... adapt your “battle plan” to it!

There's no way around this:

When it comes to UI, Android and iOS are just... worlds apart! Android taps into material design, contrasting Apple's signature flat design.

Now here are the key design elements that you should pay special attention to, along with some tips on how to make their porting... smoother:
 

• icons: each platform provides you with its rich icon library
• dialogs
• font styles: San Francisco or Helvetica Neue in iOS and Roboto in Android
• content navigation
• lists
• object placement: flat vs hierarchical object placement
• text alignment: center aligned test in iOS vs left alignment of the text in Android
• buttons: iOS “favors” flat buttons with shadows, whereas in Android you'll find both flat and floating action buttons
   

Word of caution: when porting apps to Android or from Android, keep in mind the pixels vs points (pt) difference when it comes to measuring icons and font sizes in the two platforms          
 

3rd Factor to Consider: Screen Size and Resolution 

Briefly put: it will be conveniently smoother to port an Android app to iOS than vice versa.

Why? Because in Android you have a varied collection of screen sizes and resolutions at hand, whereas in iOS it's significantly lighter.

So, if it's an app porting to Android that you're planning, do take into consideration all those screen resolutions that are missing in iOS.
 

4th Factor to Consider: Your App's Essential Architecture 

And here's the right approach to adopt when you port an Android app to iOS (or vice versa) and you're preparing to build its new architecture:

Identify the minimum OS version that your ported mobile app should support and set up its architecture accordingly. 
 

5th Factor(s) to Consider: Frameworks, Libraries, Extensions, Code

Your current app's “infrastructure” of libraries, extensions, 3rd party services and frameworks play a critical role. 

A “too critical role” not to turn it into an essential factor to consider once you decide to port your app to a new OS.

Therefore, for each one of the used libraries that's not compatible for cross-platform usage you'll need to find a suitable equivalent. And it goes without saying that this calls for:

A proper testing of each given framework and 3rd party library, to know for sure which ones support both OS and which ones don't.

The good news is that most of them do support them both, making it smoother for you to duplicate most of your app's basic functionalities when converting it to another OS.

Now when it comes to the aspect of code, the fact that the 2 platforms use different programming languages influences greatly the way you should port an Android app to iOS:

Kotlin and Java are used for building Android apps, whereas Swift is used to develop iPhone apps. Therefore, you can't get away with simply compiling your app's current code into its new ported version.

Note: I know what you might be thinking, that both OS support the C-code instead and so, that you could transfer your codebase to the other platform. Yet, it has already been proven that porting apps to Android from iOS calls for a complete rewriting in a different language.

How long would it take you? It depends greatly on your app's feature set, on the used 3rd party libraries, complexity etc.
 

Final Word 

As you can see, once you decide to create a “clone” of your iOs app for the Android platform or vice versa, you'll need to take “recompilation” out of your mind.

Porting your app won't be that simple!

With the 2 platforms having completely different user interfaces and core structures:
 

• careful planning and in-depth analysis (and yes, I'm thinking business logic here) becomes crucial
• taking into account all those elements that set these OS worlds apart (interface, navigation...) and adjusting your porting strategy accordingly is the only effective way to port an Android app to iOS or vice versa