The best way to learn is to read and that’s true for a developer as well. If you want to become a better developer, you have to read more code. It’s as simple as that.
Books, blogs, forums are all good to a certain extent but there is nothing that can replace some fully-functional, exhaustive open-source projects where the entire app with all its resources is right in front of you.
All you have to do is sit back, take a cup of coffee and read some kick-ass code. Here in this article, we bring some of the best open-source Android apps from various categories and genres to fulfill all your learning and development needs.
You can try these apps directly from Play Store to have a hands-on experience before diving deep into the code. The difficulty level attached with each app will help you to judge if you should instantly dive into it or put it aside for the time being.
Photo and video gallery apps are one of the most common apps that you can find on any Android device. Ever wondered how they are made? LeafPic is one of the best open-source gallery app you can try and learn from.
It is quite simple, easy to understand and is perfectly suitable for any beginner developer. One of the best things I have found in this app is the way they have implemented dynamic theming. It is something that many Android developers have struggled to implement properly.
A simple and easy-to-use calendar app built purely using Kotlin. If you were looking to learn Kotlin, then this is probably one of the best ways to start.
The goal of this app is quite simple which makes it perfect to get your hands dirty learning a completely new language for developing Android apps. Another cool thing you can learn from this project is to make custom desktop widgets for Android.
Amaze File Manager
Another extremely common Android app that you can find on almost any Android device, is a file manager.
Though building a file manager app might seem straight-forward at first, but it actually is quite difficult to get it right across all Android platforms and all devices.
There are a lot of good things you can learn from this app, especially how to perform proper file handling on SD cards. But I would not recommend you to follow the coding standards used in this project as it is no way up to the mark.
Easy Sound Recorder
A simple, easy-to-use and beautiful sound recorder app for Android. If you want to learn about audio recording and manipulation in Android, then this project is the best way to start your journey.
This project is very small (with just a single Activity) and very simple to understand as well. Beginners can also learn about the basics of Material Design from this project.
MLManager is a simple and straight-forward app manager for your Android device. This project is ideal for you if you want to learn how to get detailed information about the installed apps on your device, extract APKs from those apps, uninstall apps and much more.
The coding standards used in this app is quite good and should be followed. It can also give you a good idea of designing clean and simple apps following the Material Design guidelines.
A very simple and cleanly designed app which can be used to stitch photos vertically or horizontally. Sounds simple? It actually is.
It is ideal for any beginner Android developer willing to learn the basics of Android development. The coding standards are top-notch and the app has been developed keeping the best practices in mind.
You will also learn to make some simple yet useful custom views which can help you to get your foundation ready so that you can later move on to creating some really complex views in future.
(Github | Difficulty: Intermediate)
The goal of this app is pretty simple, to list the popular movies with their trailers and reviews. But what makes this project really interesting is the way things have been implemented here.
The app showcases some really cool development stuffs like MVP, Uncle Bob’s Clean Architecture, gives the sweet taste of RxJava and dependency injection using Dagger 2.
The app is quite simple but the way things have been implemented is fantastic and definitely worth a look.
Yet another simple, light-weight and minimalistic file manager designed for both phones and tablets.
There are lots of things to learn about file handling, root management, loaders, custom views, etc. from this project. It is quite well made and should not take you a lot of time to grasp what’s happening inside it.
If you are a beginner, this is a very simple yet cool project to start with. You will get a good chance to learn most of the basic and fundamental aspects of Android development.
The design of the app is decent and serves as a good starting point for beginners. But don’t follow the coding standards or package structure followed here, as they are not upto the mark and should be avoided.
Timber is a beautifully designed, fully featured music player for Android. If you ever wanted to build your own music player or any music related app, then this is the project you need to look at.
The project is quite big and is very active in development. For a beginner, it might be a bit difficult to grasp everything going on but it should be really interesting for any intermediate or advanced level Android developer.
If you are looking to learn about monitoring Android processes, memory usage, CPU usage and stuff related to these, then this is the perfect project to start with.
It’s quite small and easy to comprehend as well but the coding standard, architecture followed and overall design is not up to the mark and should not be followed.
(Github | Difficulty: Beginner)
If you are looking for a project to learn or brush up your Material Design skills, then this is just for you. This project tries to replicate parts of the Instagram app in beautiful Material Design.
There are tons of Material Design elements, animations and transitions used in this app which you can learn and implement in your own project.
It is quite simple, easy to understand and is perfectly suitable for any Android developer who wants to improve their design skills.
(Github | Difficulty: Easy)
CoCoin is an exhaustive personal finance and accounting solutionsporting a clean and beautiful UI.
If you want to learn how to manage lots of user data properly, draw beautiful charts from those data, make some cool custom views, then this open-source repository is just for you.
If you are looking to build a fully-featured note-taking Android app like Evernote, then this is just the right project for you to start with.
The project is quite big with lots of features like sharing and searching notes, attaching images, videos, audios, sketching in your notes, adding reminders and much more.
Another very cool thing you can learn from this project is to integrate your app with Google Now seamlessly.
A simple, clean and beautiful clipboard manager app for Android. The project is quite small, simple and easy to understand as well.
But the package structure, architecture, naming conventions and coding standards used in this project are not up to the mark. It has been built in a very simple and beginner-friendly way.
Super Clean Master
(Github | Difficulty: Advanced)
If you have ever used an Android device, you surely had the need to clean up some junk data from your device. And Clean Master is one of the most popular choices among all.
This app, as the name suggests, tries to emulate most of the features of Clean Master in a very clean and elegant way. But the overall project is a bit complicated and can take you some time to comprehend everything going on.
(Github | Difficulty: Intermediate)
If you are looking to build a travel based app and need to heavily rely on location and maps, then this project is probably the best place to start.
The design and the code quality of the app are not up to the mark but the overall app is really good and there are lots of things to learn for a beginner and even an intermediate level Android developer.
A simple, super-fast and lightweight launcher application for Android. There are several cool and nifty features to learn from this project.
So if you wanted to make a launcher for Android, this is probably the best way to start. The app is quite small and the project is quite simple to start with.
A simple yet quite powerful text editor application for Android. You can also use this editor to write code and it supports syntax highlighting for different programming languages as well.
I have even tried opening large text files, where most of the applications tend to crash or fail, this app handles them quite gracefully. From this project, you will have a good chance to learn making a very solid and robust text (or code) editor app.
(Github| Difficulty: Beginner)
A fast, simple and efficient wallpaper app for Android. There are tons of things to learn from this project, especially for a beginner.
The architecture followed in the app is quite good which makes this app really easy to expand and maintain. The goal of this app is quite simple but the approach taken to accomplish the goal is really appreciable.
(Github | Difficulty: Beginner)
A simple, light-weight pedometer app which uses the hardware sensor to calculate the steps taken with almost no impact on the battery performance of the device.
It is a good project to start learning step tracking, but the coding standards and design are not good enough to be followed.