Asynchrony and the infinite conveyor belt: Advanced coroutines and flows

Most likely, you already know how to use coroutines and flows. They're part of our everyday existence. But all too often we learn them through repetition and rote learning, rather than forging a meaningful understanding of what's happening deep down.
So:

- What *really* happens when you mark a function as 'suspend'?
- How come crazy things like infinite loops on the main thread are possible?
- What's the magic link between coroutines and flows?
- What, really, is a scope? A context? A job?

And there's a satisfying conclusion, too! We find that everything is linked: the path that seems to add complexity, in fact takes us back full circle.

This is intended as a vertical dive into the intricacies of a familiar topic, designed so that experienced developers as well as beginners can learn from it.

It's based on my most popular blog series on asynchrony: https://proandroiddev.com/coroutine-patterns-in-android-and-why-they-work-3bf085f53536

Android + MediaPipe + Gemma: Building offline AI-powered apps

Yes, you can run AI models locally on your Android phone! There are many benefits to this: it improves privacy, since nothing leaves the device; it works fully offline; and it saves money on cloud-based services.

In this talk I will show how to build a fully-offline Android app with AI capabilities. We'll see:
- How to run an entire LLM on your phone, thanks to MediaPipe + Gemma
- How AI can tell us what's in a photo
- How gesture recognition works on a live video stream
...and many other things MediaPipe can do

Beyond mockery: Adventures in Android unit testing

The usual "one class = one unit" approach to unit testing lacks robustness. It produces brittle tests which need to be rewritten when you refactor. It encourages developers to simply rewrite their code as a test, meaning their tests mirror code bugs. And over-reliance on mocks significantly limits the breadth of the test.

This talk presents a different approach. By focusing on user interactions, not code units, we can optimise our testing and largely solve these problems.

Through concrete, practical examples we will learn:
- How to write robust tests which don't need rewriting when you refactor
- How to tailor tests to actions users perform, not specific code implementations
- Why fakes are often better than mocks

Don't fight the architecture

Good architecture smooths the development path of your Android app for years to come. Bad architecture results in developers spending more time maintaining code and fixing bugs than adding features.

Google's best practice guidelines have changed considerably recently, and the way we develop Android apps is very different from even just a few years ago. But more important than learning the rules is understanding the principles that underpin them, so you can make your own decisions.

So what does good Android app architecture look like? This talk is all about how to be a better, more forward-thinking developer.

After a brief tour of SOLID principles (beloved of interviewers for almost any programming role), we will explore the purpose of Clean Architecture, as well as patterns like MVVM. And finally we will see how a lot of this converges in Google's Modern App Architecture, and how more recent technologies like Hilt, Kotlin Flows and Jetpack Compose make life a lot easier.

This session is aimed at seasoned developers and those looking start a career in software development. Whilst all the examples are with Kotlin + Android, the underlying principles apply whatever your language.

This is an intermediate level talk which assumes a working knowledge of programming. Whilst all examples use Android + Kotlin, the basic principles apply equally to any programming language.

Fun with Android + Bluetooth: A capture-the-flag competition

Android is the perfect platform for hacking with Bluetooth peripherals. Learning how to connect to BLE devices is not only a useful skill for professional developers, it’s also massive fun! Recent releases of Android have improved how BLE interaction works, and this session takes you through the latest Android 14.

It's built around a capture-the-flag competition: the first person to write an app to read my password, wins!

Learn:

- How to write code to send and receive messages from an Android device to any BLE peripheral
- How Android communicates with a BLE device
- All about BLE - how it works and what makes it different to Bluetooth Classic.

And when you get back home you’ll want to try out connecting with all the BLE devices you have lying around! Heart rate monitors, thermometers, proximity sensors, lights, radios, TVs, keyboards, garage doors, …

A very basic understanding of Android development is required. People will need a laptop with Android Studio and, if they want to join the competition, a physical Android device (not VM). I will bring a limited number of devices with me for those who don't have their own.