Ideally, android app development is done in Java and XML as most of the apps are developed with the use of the same. Java is used for event handling whereas XML is used to develop the User Interface.

but in some cases, you need C to develop your app which is done using NDK (Native Development Kit) and when you need to call the java function from C then there is the requirement of C++ this is known as native eventing. 

you can also design your app using HTML/ CSS, javascript by implementing the Ionic framework in Android.