How we made Basecamp three’s Android app 100% Kotlin


Our greatest recommendation primarily based on a yr of real-world transport.

Made with ❤️ in Chicago.

We began our Kotlin journey a yr in the past primarily based on two hunches: that it might 1) make an enormous distinction in programmer happiness and a pair of) wildly enhance our work high quality and pace.

I’m pleased to report that our hunches have been proper! As of this week, Basecamp three’s Android app is written in 100% Kotlin. 🎉

That places us in a novel place to share ideas from the expertise of going from all Java to all Kotlin. How do you get began? What do you have to look out for? What are the most effective methods to continue to learn Kotlin?

Learn on!

🤓 Wrap your head across the fundamentals

Very first thing’s first — take a while to get acclimated with the the language. There are free assets galore, however listed here are a number of I’d suggest:

  • Jake Wharton’s talk about Kotlin for Android. This was the lightbulb second for me. After two watches, I actually began to get it.
  • Some of my favorite Kotlin features. I wrote this a number of months after we began with Kotlin. I particularly wrote it to be fundamental and easy so it’d be straightforward for learners (which I used to be on the time!)
  • The Kotlin docs. When folks inform me to learn the docs, I usually wince. However the Kotlin docs are legit, and are a superb technique to get acclimated.

🐢 Begin sluggish however make it actual

Writing your first little bit of Kotlin is normally the toughest a part of getting began.

To alleviate the strain, folks will usually recommend you begin with exams or maybe a Gradle plugin. And whereas that’s extraordinarily sound recommendation, it doesn’t work for me. It’s too boring and obscure to get enthusiastic about.

I suggest one thing totally different — write actual manufacturing code.

That is vital as a result of 1) it’s one thing you’ll be able to see working in your app straight away and a pair of) it’s extra enjoyable! That feeling of accomplishment and seeing one thing work shouldn’t be discounted — it builds your confidence and retains you motivated.

After all I don’t suggest changing a large class unexpectedly in your first go. As an alternative strive changing a utility or helper methodology. Take a single methodology from certainly one of your util courses and rewrite it in Kotlin.

Accomplished! You now have your first little bit of manufacturing prepared Kotlin.

😵 Don’t attempt to study the entire language at as soon as

Kotlin has quite a bit of nice stuff in it — a lot that you simply could be tempted to make use of all of it straight away.

And whereas that may work, I wouldn’t suggest it. As an alternative discover a number of key ideas that click on in your mind (not what others inform you’re the greatest elements of the language), and follow utilizing these to their fullest.

Once I acquired began, three areas clicked for me: flow control (when/if/for), extension functions (add performance to any class you need), and null safety (particularly the usage of let). Specializing in simply these few ideas helped me get began with out feeling overwhelmed.

Don’t be afraid to begin small. You want area in your mind not solely to select up new issues, however to allow them to stick. You’re already going to be coping with fundamental syntactical variations — for those who attempt to cram all of the goodness unexpectedly, one thing is sure to get overwritten in your mind.

🔀 Be taught from the auto converter

JetBrains has completed a strong job with their Kotlin plugin and its means to auto convert Java to Kotlin. It might probably get your class 60–70% of the way in which there, leaving you with some tuning and idiomatic/stylistic issues to care for.

There are two nice methods to study from this:

  1. Auto convert the category, however maintain the Java class helpful. Put them facet by facet, and see how the Kotlin compares. You’ll choose up a ton by simply seeing how the auto converter selected to implement the Java in Kotlin.
  2. Auto convert the category, however don’t depart it in that state — whereas the 60% model will run, that final 40% is what makes the distinction between OK code and nice code. Assault every part for readability and conciseness and search for methods to observe Kotlin idioms that the auto converter couldn’t work out.

🤔 Query all of your Java habits

As you start writing Kotlin, the unhappy actuality is that you simply’ll in all probability have some dangerous Java habits you’ll want to interrupt.

I discovered myself writing horrible if/else blocks in circumstances the place a when could be so significantly better. I used to be writing null checks round objects when a easy object?.let would’ve been higher. And rather more.

You might also have constructed up some sturdy ¯_(ツ)_/¯ attitudes towards ugly code blocks. As a result of Java is so verbose, over time you will have begun to simply accept an occasional ugly code block as “nicely, that’s Java”.

Writing in Kotlin will allow you to see by way of these, however you’ll need to let go of the concept that ugly code is OK. Certain there will likely be occasions when ugly code could also be situationally crucial, however you received’t be capable of blame Java’s ceremony any extra.

So frequently query whether or not you might be doing one thing the “Kotlin means”. Whenever you see code that feels lengthy or sophisticated, pause and take one other have a look at it. Over time you’ll develop new, higher habits that can overwrite your Java ones.

🏕️💨 Go away the campsite cleaner than you discovered it (no new Java ever)

A great way to maintain your code on the right track is to tidy up small bits of Java as you cross by. Because the saying goes, depart the campsite cleaner than you discovered it.

A number of occasions when constructing one thing new, you’ll by the way have to make a small change to an current Java class — add an attribute, change a kind, and many others. These are sometimes small courses like a mannequin or utility class.

Convert them! Don’t be lazy and depart them be. This incremental, sluggish strategy over time will prevent and your group a lot frustration in the long term.

❄️ Use cool downs for Kotlin

A good time to work on Kotlin conversions is once you’re cooling down off an enormous launch.

Usually we’ll do our regular two week cycle, launch an enormous characteristic, after which take a number of days to look at for stability and buyer points.

These couple days aren’t going to be sufficient time to get into one thing massive, so it’s a good time to transform some courses to Kotlin. Over time you’ll get sooner at this and be capable of knock out a number of courses per day.

👴🏻 Curb your enthusiasm

Whenever you begin to really feel comfy with Kotlin, you may get a bit of…excited. That’s factor! That power and enthusiasm retains you motivated and studying.

Nevertheless it’s additionally straightforward to go overboard. I actually did.

I‘d collapse no matter I might into single-expression features to avoid wasting strains, solely to appreciate I used to be giving up readability. I’d use too many when blocks, even in circumstances the place a easy if/else would’ve been ample and clearer. I’d write extension features galore, then understand I used to be creating extra cognitive overhead than I used to be saving.

It’s great to be enthusiastic and use all of the instruments that Kotlin provides you. However attempt to maintain your cool (not like me) and ensure you’re utilizing language options for the precise causes.

💸 Don’t neglect about your prospects

Whereas seeing increasingly Kotlin makes your life significantly better, you must maintain one essential (apparent?) factor in thoughts: your prospects don’t care.

I absolutely help the argument that programmer happiness results in nice code and finally a greater product. It’s crucially vital.

However as with all good issues, you must discover the precise stability. Changing all of your Java to Kotlin could be a enjoyable aim for you, however in the meantime your prospects could be battling a nagging bug.

The nice factor is that these two issues aren’t mutually unique. Seize these bugs and squash them with Kotlin — it’s a win-win! (If we’re being trustworthy, Java in all probability induced the bug within the first place anyway).

👯 Don’t go it alone

Relying in your firm make-up, this could be simpler mentioned than completed. However for those who can, discover a Kotlin buddy!

There isn’t any query that I’m more adept at Kotlin due to my buddy Jay. We frequently share concepts, evaluate one another’s Kotlin, and poke enjoyable at Jamie, our designer.

Generally that stuff occurs in casual chats, however the by far essentially the most priceless place to study is in pull requests. You possibly can let your code communicate for itself, and the suggestions can do the identical. With regards to studying Kotlin (or any new language actually), that is completely essential.

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