What languages do Android developers need to use?

Android is a Linux-centric mobile phone operating platform, as an open-ended operating system, with the rapid development of Android, now allows developers to use a variety of programming languages to develop Android applications, It's no longer a single scenario where you can only use Java to develop Android apps. So, what languages can the Android system use to develop?

In Android, developers can use Java as a programming language to develop applications, or they can use the Android NDK as a programming language to develop applications, or you can use SL4A to program in a variety of other scripting languages such as: Python, Lua, Tcl, PHP, etc.).

There are other well-known programming frameworks, such as Qt for Android and Mono for Android, which also start to support Android programming, and even through monodroid, developers can use C # as a programming language to develop applications.

In addition, Google in 2009 launched a special Android simple language for beginners, which is similar to the basic language. In the context of Web programming languages, Javascript,ajax,html5,jquery, Sencha, Dojo, Mobl, PhoneGap, and so on, have supported Android development.

In addition, Google has launched the Google App Inventor development tool, which can quickly build applications to facilitate novice developers.

What languages do Android developers need to use?