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Hello, Kotlin! Converting an Android Project – Part 2

January 24, 2017 10:37 AM

I was trying to convert an Android project to Kotlin in Android Studio via the Kotlin plugin. If you haven’t read part one (you can always do it now), then I’ll briefly tell you that it’s up to you to choose how many classes to convert. I chose them all. The conversion caused numerous compilation errors and practically swayed me to convert one/two classes at a time. Even though solving compilation errors was a great way to learn, I still had an ambition – convert my MVP example project from Java to Kotlin code.

Therefore, I decided to attack it from another angle. My second approach was less messy – one or two compilation errors per conversion, albeit it took me a couple of hours to get everything working.

In the following post I will cover:

  • Adapter’s getView() runtime error, caused by the conversion
  • Kotlin pros/cons for Android developers
  • Verbosity comparison of Java vs Kotlin

TL;DR Conversion might cause errors but Kotlin will reduce NullPointerExceptions, and minify your code into a much more readable version.

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The Holy Gradle: Setting Up Your Android Build on a Build Server – Part 2

July 15, 2015 8:11 AM

In my previous post I went over some basic terms used by Gradle and the Android build system, and over the flow of the build. With these understandings at hand, we are now ready to go over concrete steps and set up our build server, without Android Studio, or in fact without any GUI tools at all.

For the sake of this post I will assume you are setting up your new build environment on a Linux server, and you don’t have the Linux GUI at your service, only the command line. Of course, it can all be set up on a Windows or Mac machine just as well.

Let’s also assume that your user on the build machine is called “user”, and therefore your typical home directory would be /home/user.

Now let’s go step by step:

1. Download and install the JDK

First download the JDK you work with. I have downloaded JDK7 from Oracle’s site. If your Linux environment doesn’t support rpm – you will need to download the tar.gz version and extract it, for example to /home/user/.

2. Download and install Gradle

You can download Gradle’s latest release from here. The binary distribution will do, no need for the complete distribution. I chose to use Gradle 2.4.

By the way, There is the option of avoiding the explicit installation of Gradle if you are using the Gradle Wrapper, but let’s leave this topic aside. Personally I think that if you are setting up your build server, the better approach is to explicitly download the Gradle version you want. Once downloaded, extract the zip file, for example under /home/user.

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The Holy Gradle: Setting Up Your Android Build on a Build Server – Part 1

July 7, 2015 10:47 AM

If you are using Android Studio, then you’ve seen Gradle in action. Yep, Gradle is the engine behind the build system used in Android Studio, which is, together with Google’s Android plugin for Gradle, responsible for building your Android application and producing the final .apk files.

Gradle is a powerful build tool, written in a simple script language called Groovy. It takes care of a lot of the plumbing related to building an application – resolving dependencies, downloading artifacts from repositories and determining which tasks need to run in order to build your app. Gradle then runs the tasks that compile, merge, handle resources etc until your app is ready. Gradle is also simple to configure. Typically, with a few declaration lines in your build.gradle you are ready to go.

But this is exactly what makes Gradle somewhat complex to understand, because a lot of the work is done under the hood, typically by plugins, some built-in (like the java plugin), and some being 3rd party plugins, like the Android plugin and the SafeDK plugin. If you are someone like me that likes understanding what’s going on behind the scenes – it’s not always that easy.

There’s of course a lot to tell about Gradle and the Android build system. So much, in fact, that this is just the first out of a two-part story (part 2 coming next week). In these couple of posts I’ll focus on a specific topic – I’ll try to guide you through setting up an environment where you can compile an Android application using Gradle, but without the Android Studio IDE. Why would you want to do that? Well, it has to do with buzzwords like “build server”, “continuous integration” etc. While you can build and deploy your app in Android Studio, if you have multiple people working on the app, you may want a central build server with a consistent environment, where you continuously integrate, run automated tests, produce versions for your QA team and produce the final versions. This is btw one of the nice things in Android Studio – the fact that you can completely decouple the build system from the graphical IDE.

Here I’ll go over some terms and mechanisms which are essential for part 2, where I’ll detail the steps to set up your independent build server.

OK, so let’s dive in.

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