A 2-D development platform with a focus on games. Can be used to create other types of mobile apps too. Free.
Editors and IDEs
Android-IDE
A complete web and Android development environment, it also allows you to edit Java and PhoneGap apps. Smart code completion, life error checking, refactoring and code navigation.
DroidEdit
A text and source code editor for use on Android platforms. Edit your files directly from the cloud. DroidEdit works with Dropbox, Drive, Box, (S)FTP servers and Git.
Eclipse
Prior to Android Studio, Eclipse was the official Android development environment. It can be used to code Java but can also be expanded to other languages via plugins.
Android Studio
The Official IDE for Android.
Xamarin
Build native apps for multiple platforms on a shared C# codebase. Use the same IDE, language, and APIs everywhere. (C#)
Titanium
Write in JavaScript, run native everywhere. Titanium is a cross-platform tool for mobile app development. (JavaScript)
Telerik
Telerik Platform is a modular platform for cross-platform mobile app development that integrates a set of UI tools with cloud services. (HTML5)
RFO Basic
RFP Basic is a dialect of Dartmouth Basic that allows you to write and run programs directrly from your Android device. BASIC! programs may be compiled into stand alone applications that do not need BASIC! installed. The resulting applications can be offered on the Google Play Store. (BASIC)
RAD Studio XE
RAD Studio is a fast way to write, compile, package and develop cross-platform native applications with cloud services. Integrated app-store packaging. Cross-platform UI framework. (Object Pascal, C++)
PhoneGap
Reuse existing web development skills to quickly make hybrid applications built with HTML, CSS and JavaScript. Create experiences for multiple platforms with a single codebase so you can reach your audience no matter their device. (HTML5)
NS BASIC
NS Basic is a family of development tools. The AppStudio product consists of an IDE, a programming language and a deploy module. The IDE and programming language are modelled on Microsoft’s Visual Basic. The runtime environment is based on JavaScript, HTML5 and WebKit. Apps install themselves as offline web applications. (BASIC)
MonoGame
MonoGame is an Open Source implementation of the Microsoft XNA 4 Framework. It allows XNA developers to port their games to Android. “Write once, play everywhere. One framework for creating powerful cross-platform games.”
(C#)
Monkey X
Monkey is a games programming language that allows you to create apps on multiple platforms. It works by translating Monkey code to one of a different number of languages at compile time – including C++, C#, Java, Javascript and Actionscript. (BASIC)
MIT App Inventor
MIT App Inventor is a beginner’s introduction to programming and app creation that transforms the complex language of text-based coding into visual, drag-and-drop building blocks. The simple graphical interface grants even an inexperienced novice the ability to create a basic, fully functional app within an hour or less. (Blocks)
Lazarus
Lazarus is a Delphi compatible cross-platform IDE for Rapid Application Development. It has variety of components ready for use and a graphical form designer to easily create complex graphical user interfaces. (Pascal)
Kivy
Open source Python library for rapid development of applications
that make use of innovative user interfaces, such as multi-touch apps. (Python)
IntelliJIDEA
IntelliJ IDEA is an IDE by JetBrains. It primarily supports Java development, but also supports JavaScript, Groovy, HTML, CSS, RSS, R, Haskell, PHP, Ruby, Python, Scala, Swift, Clojure, Kotlin, Hybris, Gradle and others. (Java)
Intel XDK
XDK is an Integrated Development Environment for creating IoT applications using JavaScript. With it, you can connect and build IoT applications using JavaScript on the IoT device. You can extend your application to your phone or tablet to control or read data from the IoT device by creating an HTML5/Cordova companion app. (HTML5)
Corona
Corona is a cross-platform framework that allows developers to create 2D games and apps using Lua. (Lua)
Cordova
Mobile apps with HTML, CSS & JS. Target multiple platforms with one code base. Free and open source. (HTML5)
Basic4Android
B4X programming language is a modern version of Visual Basic. (BASIC)
Application Craft
Visual development in the cloud. Lets you building mobile and desktop applications with a web-based, drag-and-drop IDE. (HTML5)
AIDE (Android IDE)
AIDE is a complete integrated development environment for your Android device. (HTML5/C/C++)