mDevCamp 2020 – A Conference for Mobile App Developers

Ash presented several Kotlin features such as nullability checks, beans, extensions. 

Then, he talked about offensive and defensive code and what are the differences between them. When you write defensive code, you add a lot of null checks but using offensive code makes it easier to detect errors, as they do not get propagated.

And finally, here’s something to keep in mind when converting a class to Kotlin. Sometimes, the conversion can cause the file history to be lost, which can often be a problem. 

CameraX is a library which can help you add camera capabilities to your apps. As we are taking more and more photos with our devices, we need better solutions for apps which have camera features. 

CameraX solves some of the problems we might encounter during development. Some of these helpful features are device compatibility (supports about 90% of current devices), lots of tests and a large device farm, low complexity and easy implementation.

This was a very insightful talk about app architecture, performance and working with image data in apps. 

Among the main issues affecting our apps’ performance is memory. We can improve the performance of our iOS apps by keeping data in the first two levels (L1 & L2) of memory cache when rendering graphics. CPU is pretty fast nowadays but L3 and the main RAM memory are pretty slow.

Create data-oriented design instead of focusing on object-oriented programming. Instances don’t have to be class instances, they can be named with a reference ID. 

Richard talked about problems with client caches (Programming Models), problems with concurrency (Convergence and Correctness), the role of GraphQL and understanding & using Amplify DataStore. 

The Amplify Framework provides a set of open-source libraries, a command-line interface and UI components that allow the user to develop backends faster and integrate them with cross-platform (iOS, Android, Web and React Native) apps.

During this talk, we learned about new ways we can implement effortless navigation in our Android apps. 

We started with the Principles of Android navigation:

1. Fixed start destination;
2. Navigation state is represented as a stack of screens;
3. Up and back buttons are identical within the app’s task.
4. The Up button never exits the app.
5. Deep linking simulates manual navigation.

Tomas discussed ways we can improve our apps with code generation. Using code generation saves time, increases code quality and speeds up the entire development process. 

The first step is to find some patterns in code, anything written twice is a boilerplate code or is missing an abstraction.

Then, as a solution, you can use GenGen, a template-based code generator. The main goal of this tool is to create a code generator for anything the user might want to generate.

To successfully reverse an app, there are 3 main steps you can take. First, you have to get to know the app pretty well. Then, you should perform static analysis and finally a dynamic one to understand the code structure of the app.

Protecting against these steps:

• Adding Proguard or other paid alternatives for code obfuscation;
• Writing sensitive code in native (NDK);
• Implementing root/debugging checks;
• Using SSL certificate pinning;
• Preventing repackaging by checking the signing certificate when the app is launched and closing the app if the certificate does not match.