I presented some work at Droidcon London 2018 on a particular problem I had solved using Android Path APIs nearly 2 years ago. Here I flesh out the problem and the steps that I took towards a solution. Project linked here.


I came across a problem on Stack Overflow in which an original poster wanted a custom progress view containing text within it. And this text needed to change its colour based on the background.




So when the background is orange, the text is white; when the background is white, the text needs to be orange. There is a similar problem related to underlying text by Romain Guy that introduced me to Path APIs for the very first time.


Why this particular problem?

I saw this problem posted in our local Android community Slack chat. I knew how to solve it thanks to Romain Guy’s article. I spent 3-4 hours building this animation where the color of the text changes based on the background. I finished the project, pushed it online, and made it open source here. I presented this solution to the original poster (OP) and it was exactly what they were looking for, and they were quite happy.

Tech behind the solution: Android Path APIs.

We started off with an introduction to set theory in order to help the audience understand the concept of operations that we applied to shapes, but in simpler terms using numbers. (The audience interaction was great fun ^_^ But we’ll skip that for now).

There are two parts to this:
— Left Hand Side (LHS): Curved rectangle with parts of text removed from it.
— Right Hand Side (RHS): Text with parts of curved rectangle removed from it.

Place LHS and RHS next to each other to create the complete animation.

When the seekbar position is updated, we update the width of the curved rectangle.










Place LHS and RHS next to each other and we get the full animation.













Conference Experience

My peers at Obvious were extremely supportive in helping me prepare for the talk. We had four rehearsals together. I did 20+ rehearsals on my own time to ensure the talk ran smoothly and the jokes landed!


I was very excited to take my first flight, and that it was an international flight to London. It was almost unbelievable, having pre-conference casual conversations in the party with Android developers I had followed for so many years. I met many cool Android devs working at Google, Facebook and other places. I got to speak to Android legends like Christina Lee, Jake Wharton, Stacy Devino and Florina Muntunescu. And of course, London was beautiful and extremely kind to me 🙂


The conference was huge and had thousands of people attending. There were 5 parallel talks all the time. I got to learn about interesting things in the Android world like Architecture Components, Android security, Coroutines and others.




London personal experiences

I had a good time on my own too! Cheese tasting, whiskey tasting, burgers, the Tower Bridge, Apple HQ, watching  The Play That Goes Wrong, pub-hopping with new friends, shopping and so much more!


Link to talk: http://uk.droidcon.com/skillscasts/12249-exploring-android-path-apis 


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