Android KTX: Kotlin Development for Android

https://android-developers.googleblog.com/2018/02/introducing-android-ktx-even-sweeter.html

by ingve • 8 years ago

164 73 8 years ago

android-developers.googleblog.com

bitwize2• 8 years ago

Still working in Java on Android. Have a feeling that I will be left behind soon.

wootie5122• 8 years ago

Same here. On my my most recent project the client requested we use Java, since after they take over they can use devs with Java knowledge.

firefruit• 8 years ago

It will take a week or two to convert experienced Java devs to Kotlin.

shrewduser• 8 years ago

you really wont be, it's like a couple of weeks and you'll be up and running in kotlin.

bitwize2• 8 years ago

I don't mind Kotlin, but I don't want to get a big middle finger from Google for choosing to remain with Java for this project I already started in Java.

BoorishBears2• 8 years ago

I’ve used Kotlin enough to be comfortable but Java is still my go to for personal projects.

Java + StreamSupport + RxJava (and formerly + Retrolambda) is a very modern feeling language.

Heavy use of Optional makes the null safety issues a little less worrying and all my apps are built around AutoValue objects which are a bit like Kotlin data classes.

mrath• 8 years ago

And apparently Java 10 has ,`var` keyword. It won't be long before Java has all the goodness.

saagarjha4• 8 years ago

We've already seen something similar before: when Apple "modernized" many of the their Cocoa Touch APIs to work better with Swift.

Techonomicon• 8 years ago

What does "already seeing this" have to do with any meaningful input on the subject?

saagarjha4• 8 years ago

I was providing a parallel from my experience, which I thought might foster discussion on how such an API improvement might proceed based on historical anecdotes. Was this not a welcome addition?

1123581321• 8 years ago

Can you elaborate on what we have seen? Modernization in quotes suggests that Apple wasn’t successful.

saagarjha4• 8 years ago

I put modernization in quotes because in most cases it was really a shim placed ontop of the existing Objective-C API that changed some names or parameter types; so, in this case it wasn't quite as extensive as a Java->Kotlin transition would be since Objective-C already supports many "modern" features such as closures.

jchw• 8 years ago

I thought that was purely just Swift's own translation layer to make Objective C APIs more Swift-y, not an API change.

euyyn4• 8 years ago

There were API changes to make the translation happy, in many cases where conventions weren't being followed strictly.

merb2• 8 years ago

some examples are fine, but come on...

Uri.parse(myUriString)

vs.

myUriString.toUri()

I'm not sure if I would prefer the second one...

kornish2• 8 years ago

Discoverability via autocomplete is much higher in the second one. Extension methods probably seem really strange to anyone coming from a FP background (myself included), but in practice they've ended up being pretty useful when paired with Intellij.

TheAceOfHearts3• 8 years ago

Doesn't it get a bit overwhelming to get a huge list of choices with autocomplete? I've never done any serious work with Java or Kotlin, so I'm genuinely curious.

As long as you have good docs, I find discoverability is rarely an issue. One of the first things I do when picking up a language is look through its built-in constructs, to familiarize myself with the available options.

merb2• 8 years ago

Well I'm coming from a FP background. But if you're String needs to have a toUri() method, things are already wrong. Uri.parse is just fine, even in scala.

rubber_duck4• 8 years ago

I don't like this because it forces you to use the tool, and even if you do I've seen so many times when IDE breaks down and won't autocomplete, navigates to compiled binary definition on a same solution project reference, fails to find extension methods so you need to Google which namespace to bring in to get it (which isn't always as simple as class.method search, especially when reading code example snippets), etc. Admittedly this was Visual Studio/C#, never used Kotlin for anything serious.

I see extension methods as an inferior substitute for free functions and piping/chaining operators in C#

TheAceOfHearts3• 8 years ago

I was about to post the same thing. The first one makes way more sense to me.

BoorishBears2• 8 years ago

It’s weird watching old things become new again.

I know C# didn’t do it first, but I’m only old enough to remember C# doing it... and watching people learn the hard way that extension methods pollute the global namespace very easily.

This would be a textbook example of what not to use extension methods for, adding a very specialized extension to a basic type where a simple static utility method would suffice.

evancox100• 8 years ago

Why is it that these large web companies can put out such sophisticated tools, and yet can't make a functional web page? Literally cannot see the content you are trying to show me.

https://imgur.com/a/lXY8J

And no, there's no scrolling or zooming allowed.

Seriously, let's stop the focus on web framework du jour and actually make web sites that work, please.

agildehaus• 8 years ago

There's more chance for human error at a large company.

Looks like it could be fixed by adding a CSS "white-space: pre-wrap" to the <pre> elements they're using to display this code.

dguaraglia• 8 years ago

Well, if you think about it in terms of priority, making better tools that literally millions of engineers will be using to develop apps for billions of people has a higher impact than improving a blogging platform that is used by a handful of people at Google.

That's not to excuse the shitty state of web on mobile, but let's face it: we are talking about completely different teams and priorities.

vesinisa• 8 years ago

You may notice that Android KTX uses package names that begin with androidx. This is a new package name prefix that we will be using in future versions of Android Support Library. We hope the division between android.* and androidx.* makes it more obvious which APIs are bundled with the platform, and which are static libraries for app developers that work across different versions of Android.

Ugh, okay. It's going to be a blast refactoring all my existing code and custom tools to reference this new package.

jontro• 8 years ago

Hopefully just a couple of simple global search and replaces? Anyways I think the current support library structure is confusing and it's a good thing that they will refactor it.

izacus2• 8 years ago

Android Studio handles that pretty well and it'll probably fix most of those in a single "Optimize imports" pass.

on_and_off• 8 years ago

Absolutely, it sounds like something that tools can handle for us or that would not take long to change even on a large codebase anyway (because you would just do a pattern replace)

mncolinlee4• 8 years ago

It's worth noting that one of the great features of Kotlin is how it simplifies deprecating code and writing quick fixes. This is why Google scrapped Java for writing Lint rules entirely. I expect a simple Option-Enter may resolve these kinds of issues across an app.

https://www.youtube.com/watch?v=p8yX5-lPS6o&list=PLQ176FUIyI...

barbs• 8 years ago

Not to be confused with Kotlin Android Extensions, which although handy is really just a convenient way to reference views in XML.

https://kotlinlang.org/docs/tutorials/android-plugin.html

wiradikusuma• 8 years ago

Maybe a combo of that and Anko (https://github.com/Kotlin/anko)?

mncolinlee4• 8 years ago

Kotlin Android Extensions is a tad more than that. It's also a View cache that grabs all view references in a single pass. I routinely have to explain to other senior Android developers that findViewById() traverses the entire view hierarchy until it finds that ID each time you call it. This won't be noticeable with simple views, but becomes a bigger problem as complexity increases. Which also results in more wasteful calls to findViewById().

Android Data Binding does something very similar to Kotlin Android Extensions, which is why it also perplexes me to see experienced devs bind a model to a view and then call findViewById() to alter it. I'll see calls to binding.getRoot().findViewById(), which is crazy redundant.

MBlume• 8 years ago

Curious, is anyone inside of Google using Kotlin for their Android apps, or is this all for third party developers?

euyyn4• 8 years ago

I know of one app for sure, but I don't know if I can tell :)

mncolinlee4• 8 years ago

I heard the Android data binding compiler was written in Kotlin. At KotlinConf, they announced that Google had dropped Java altogether for writing Lint rules because of Kotlin's much greater capabilities for handling deprecated code and IDE quick fixes.

ptx• 8 years ago

Wasn't the linter thing just about moving the lint rules (for checking proper Android API usage) to a language-independent format so that they could be shared by Java and Kotlin? Previously they only worked for Java code.

daram• 8 years ago

Director of project management, Android, said of Kotlin last July: "we're already using it ourselves to write code in Android Studio which gives us more ideas for making our support even better." https://adtmag.com/articles/2017/07/20/android-ama.aspx

Rockvole• 8 years ago

As an alternative to learning Kotlin on Android, you can spend the time learning flutter. Then you get concise code which works on Android and IOS now and on other platforms in the future - including desktops.

k__2• 8 years ago

I found all the "new" calls rather clunky, does Flutter has something like hyperscript-helpers or JSX?

Zerocchi• 8 years ago

There's a discussion on github about jsx-alike syntax on Flutter (https://github.com/flutter/flutter/issues/11609), and "new" keyword will be optional in Dart 2.0.

nolok2• 8 years ago

And it's made by Google, unsurprinsingly.

A big plus for Kotlin is that being a jetbrains project, it has top of the line intellij tooling support right at release date.

Anm• 8 years ago

Flutter's dev tools are built on intelliJ.

ClassyJacket• 8 years ago

If it's made by Google, shouldn't we avoid it as it's likely to be discontinued in a few months?

oweiler• 8 years ago

Except Dart is a worse language than Kotlin.

bsaul• 8 years ago

Flutter is definitely on my watchlist but i’m still waiting for them to solve the map and videoplayer issues to bet my future on it.

tiuPapa• 8 years ago

I am just asking here and not contradicting, but then isn't React Native too an alternative to learning Kotlin?

therockhead• 8 years ago

Can you point to any apps in the App Store using flutter ? Would be nice to see some real work examples in action.

vorg• 8 years ago

Laughed when I saw this Apache Groovy code slinking away at the bottom of the article:

To start using Android KTX in your Android Kotlin projects, add the following to your app module's build.gradle file:

  repositories {
    google()
  }

  dependencies {
    // Android KTX for framework API
    implementation 'androidx.core:core-ktx:0.1'
    ...
  }

swsieber• 8 years ago

Yes - that's Gradle's language de jour right now, though there is a ton of effort being put into supporting Kotlin as an alternative scripting language for it. I think you could use it right now actually.

karag• 8 years ago

Florina killed it again! go go girl (She's a genius)

Android KTX: Kotlin Development for Android

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