Blog

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Are you using a VPN on your mobile device? Do you need to disable that to access your development web server over MDNS on your mobile device? Well… read on to simplify your workflow.

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As developers, we love to build cool things and ship them as fast as reasonably possible. And to get that done, here are a few things you can do to “game the system”.

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Tired of building un-versionable, lifeless architecture diagrams? Wouldn’t it be great if you could add your diagram to Git, embed it in your documentation, and have clickable elements?

3 minute read

Planning an event can be stressful, and the last thing you need is worrying about your guests’ privacy. But don’t worry, I’ve got you covered with a privacy-friendly RSVP option.

less than 1 minute read

Looking to configure multiple SSH keys on the same computer? For instance to use a different SSH key for your public and enterprise Github contributions.

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These past years I’ve grown to be more privacy-aware. And while this post isn’t about how I’m increasing my personal privacy, I’d like to talk about how I’m increasing yours.

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How can you connect your app on an Android emulator to a development server running on the localhost of your computer?

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Trying to get a large number of files from your Android phone, but Android File Transfer freezing up?

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Looking to get a fancy verified checkmark on Mastodon for your Github account?

less than 1 minute read

Traveling by train or plane and want to test your react app on your mobile phone? This quick post explains how to access your react development server from your phone without a Wi-Fi connection.

3 minute read

WorkManager is great to schedule background work on Android. However, since scheduled work lives outside of the app lifecycle, you might run into unexpected crashes.

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In the past years, my thoughts on pull request reviews have evolved considerably. Given that creating and reviewing pull requests are a core part of our work, let’s talk about those.

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With JCenter shutting down, many are migrating to Maven Central. And while there are many posts on how to publish new artifacts, also all existing artifacts should be migrated away from JCenter.

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While Android supports most Java language features, it doesn’t support every API that Java provides. On the other hand, Kotlin multiplatform only allows sharing code across all targets (commonMain), not a subset of targets (commonJvm).

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This week JFrog - out of nowhere - announced to completely remove their Maven repository. Since they’ll pull it offline already by May 2021 (!!!) it’s time to urgently migrate away. This blogpost will guide how to get started.

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Well… I don’t really know where to start this time. 2020 was quite the rollercoaster, with many downs… but fortunately also a few amazing ups. Let’s focus on the good stuff.

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Short, powerful post on how to test the release version of libraries directly within a project without having to deploy them to Maven first.

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Ever had a build failure while integrating an SDK? Wonder how you can avoid your SDK customers having dependency conflicts? How many transitive dependencies should your SDK have?

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With modularization being all the hype, should you also modularize an SDK? Are fat aar files really needed? And how do you prevent internal APIs from being exposed on your public interface?

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Having switched to Android SDK development over the past year, I’ve run into quite a few interesting and unexpected challenges. So how does library development differ from app development?

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A great way to make your library easier to use it to generate code documentation for its public interface. The default way to do this in Kotlin is to generate KDoc using the official Dokka plugin.

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Getting up without being rushed, cycling my kids to school, cooking healthy salads for lunch, kids running into my arms when they get home… I’m quite happy with my new daily routine!

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Now that we know how feature flags can help us release faster, it’s time to dive into the actual implementation details. How can we easily define feature flags? How to configure them both locally as remotely? And use them in...

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Empowered with what feature flags are and why they are useful, let’s see how we can actually integrate them into an app. And how can we roll them out to our users?

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A key ingredient to speed up modern software development is feature flags. But what is a feature flag precisely? Why should you care about them? How do you integrate them into your codebase? And how can we make them easy...

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Three years ago, we decided ramp up internal app development at Philips Hue. After interviewing candidates (78!) for six months, I became the lead Android developer of the freshly hired Android team.

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From Android Q onwards devices can now operate in a fully gestural system navigation mode. In that mode, there is no longer an on-screen back button, instead users can swipe from both edges to navigate back.

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Your icon is one of the most important assets in your app. With a bit of luck, users might even put it on their main launcher screen!

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Wrapping up this series on modularization I’d like to share some of the things we’ve learned at Philips Hue while going through this process the past year.

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Now that we have a clear idea of how a modularized app could look like how can this be applied to an existing app?

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With a clear view on how multi-module apps should be architected, let’s dive into a real-life practical example.

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Now that we’ve established that modularization is a really good thing to strive for, how should a modularized app look like? How are the different modules connected? And how does this look for a real app?

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Modularizing your app seems to be all the hype these days. But why should you actually care? What are the benefits for you and your team? How should a modularized app look like? And how do you start splitting your...

7 minute read

Are you living the dream? Is your code so clean it makes your eyes just tear a little? Can’t think of anything you would still like to refactor? Never have any bugs? Using all the latest technologies?

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Architecture components are one of the most exciting things that happened to Android in the past years. But how do you effectively go about and testing this?

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Sitting in our own couch, in our own house, kids safely asleep upstairs,… The road here was brutal, but the result is extraordinary.

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Learning from analyzing code is one of the greatest ways to improve your skills. Can you spot the mistakes in the tests below?

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Java interop is one of the best features of the Kotlin language, yet sometimes this also can cause unforeseen issues…

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Was really great visiting Kotlinconf this year and I wanted to do a quick post to link to all of it’s wonderful content.

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Kotlin is an incredibly enjoyable, concise and powerful programming language. Yet sometimes also a bit confusing…

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This is a post-mortem where the very dangerous permission, READ_PHONE_STATE, unintentionally sneaked into our app. Here’s how this could happen, how we debugged and finally how we solved it.

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Not only can anything in Android Studio be controlled with a keyboard shortcut, it offers many more simple tricks to make you more productive.

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Refactoring can be tedious and easily introduce bugs. The main reason for this is the number of manual steps involved: rename, move, copy-paste,… So wouldn’t it make sense to automate this and have Android Studio do all the work for...

4 minute read

Struggling to navigate your code? Getting lost in deep inheritance hierarchies? Hard time figuring out relations between classes? Let’s learn how to navigate code in Android Studio like a pro.

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For the first time ever I have my year in review ready in time.

less than 1 minute read

Tonight after a routine MacOS update (10.13.2) disaster struck and my Mac got stuck in an update boot loop. After a few hours of panic, reading online and trial & error I managed to resolve it. Here’s what I did...

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Do Fragment transactions and back navigation have no more secrets for you? Well then you should try to solve the mystery in this post, where a Fragment (literally) came to haunt us…

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While you may be tempted to strive for 100% code coverage, that would be a horrible idea. Besides some code being hard to test, the concept of coverage is actually fundamentally limited.

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Had a blast visiting Droidcon UK this year and wanted to do a quick post to link to all of it’s wonderful content.

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This isn’t another post about the benefits of using Kotlin. Hell, I’m not even going to cover any of its language features. Nor will I try to convince you to make the switch.

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For years Android developers have been limited to Java 6 features. While RetroLambda or the experimental Jack toolchain would help, proper support from Google was notably missing.

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Upgrading to Android studio 3.0 territory will make building multi-module projects a lot faster, but it also means a breaking Gradle plugin API change unfortunately.

3 minute read

Being my 2nd year at Google IO, I decided to do things differently: Besides taking notes during sessions, I also created a personal todo list. This contains all new (and even old) technologies I got triggered to look into.

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After organizing Droidcon Paris for several year, the organizers decided to move on and experiment with a new format. This didn’t just result in a well organized conference, but also in a fresh new vibe whilst still feeling familiar.

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Too many times I’ve seen developers trying to avoid crashes at all cost. But are unhandled exceptions really that bad? And are null checks really the answer?

3 minute read

If you can code, you can also write unit tests. Writing awesome tests on the other hand is a different story. Don’t fool yourself: Unit testing code is production code that you will need to maintain, refactor and build upon...

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The Mockito team is on fire lately! Not only did they add support to mock final classes and methods, but now they allow running Mockito directly onto an actual Android device.

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It’s that time of the year again to do a little personal retrospective.

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Due to its clean simple api, Mockito has become world’s most popular Java mocking framework. After having covered all of its basics, it’s time to spice things up and start extending Mockito.

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Code coverage is an awesome way to motivate you and your team to write more tests. But did you know that simply enabling it slows down your build significantly?

4 minute read

As die hard Android developers, copyright notices are usually not on top of our priority list. Yet large corporations always insist to add a copyright header. Why do they do that? Should you do that for your open source libraries?...

4 minute read

Cycling is all about exploring: visiting new places and making existing routes more fun with better streets. So there must be an app that allows to plan your route and start cycling right? Think again… there is currently no solution...

1 minute read

At Droidcon Berlin 2016 I had a great time talking about testing using the Mockito framework. While the talk wasn’t recorded unfortunately, the great folks at Voice Republic recorded an audio version which you can listen to as a podcast...

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Having founded the entire Droidcon franchise in 2009, Droidcon Berlin is a magical conference to be at. Not only do they have an awesome lineup of speakers (including yours truly). But they also organize great after hour events. Further they’re...

6 minute read

As green field projects are a rare breed, chances are that you’ve inherited a legacy code base. If you’re as lucky as me, that code base has over 65k methods causing the build times to be boringly slow.

4 minute read

A conference about our favorite Green little robots? In sunny Italy? With great food and a party? Yeah, I can image how you must feel in case you missed it… I on the other hand was fortunate enough to attend...

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Do you remember the last time you had to dig into strings.xml to find the right String to use? Or that you manually had to go over all drawables to find the one you needed?

4 minute read

As my previous blogposts already covered how to set up a private Maven repository, you might wonder “Why again a Maven blogpost?”. Well that’s a fair question and the answer is twofold:

1 minute read

Finally found the time to write my year in review. #insomnia

8 minute read

Wouldn’t you love to have your open source projects built automatically by a continuous integration server? And to have a detailed code coverage report for all your unit tests? Even when someone generated a pull request? And how about having...

7 minute read

My previous blog post described how to set up your own private Maven repository with Artifactory in 30 minutes. This second and final part will make things more interesting and take your setup to the next level.

5 minute read

Setting up your own Maven repository and uploading artifacts to it is quite a daunting task. As I went through this experience myself recently, I want to help others in setting up their own Maven repository via Artifactory and automate...

7 minute read

For quite some months, I’ve been planning to create a website and start blogging about the things I’m passionate about. Last week, I finally decided to setup a portfolio and blog using GitHub pages and Jekyll.