Optimizing 0.9.2

0.9.2 doesn’t contain any new features, but does contain a lot of optimizations. Here is more detail on some of them.

Tic-tac-toe Collection is built using Xamarin Forms. This post assumes familiarity with Xamarin, Xamarin Forms and .NET. I do have another post planned with more detail on these steps for those less familiar.

Firstly, I enabled Proguard, a toold for stripping out unused code at the Java byte code level. Doing this for Xamarin is a bit weird because the version of Proguard you get by default does not work if you are targeting Android 7.0 or newer. A Nuget package is recommended but that didn’t work for me either due to some path issues. So I just extracted the jar and specified the path manually.

I grabbed an example Proguard config file off the internet, added some extra bits I found elsewhere for Google Ads, and tried to run it. I worked through the errors about missing things, adding to the config file as I went. On the whole, actually straightforward.

The next step was to enable “link all” in the Xamarin linker settings, to remove unused code at the .NET level. This time however, instead of immediately excluding things from linking that caused problems, I realised I could actually reduce the number of things only referenced using reflection.

By default Xamarin Forms uses reflection heavily when data binding. This can be largely avoided by using compiled bindings. To use it you need to do two things: firstly, enable XAML compilation (which you should have been using already); secondly, add appropriate `x:DataType` properties to your XAML.

This underused feature allows the compiler to generate strongly typed bindings based on the type you specify.

After doing that, the only things left that the linker was breaking was types used in JSON serialization, which were easily fixed.

The final thing I did was to replace Autofac. Autofac was the first IoC container I was introduced to and has been my default choice, pretty much without any thought. However I came across this chart of IoC performance and realised I was not using any of the clever features that justified Autofac and so, switched to LightInject.

Enabling Proguard and the linker cut the APK size down from about 32MB to 22MB. The improvements from the compiled bindings and Autofac changes are harder to measure.

The most notable improvement is cutting in half the time to go from the main screen to the game screen directly, and all of the steps will have helped.

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