The tools you will use for Android development depend on how you would like to focus your career as an Android developer. If you plan on focusing on native Android app development, you should know one or more of three programming languages: Java, Kotlin, and C++. Java and Kotlin are popular with a number of organizations that build their app natively. C++ is the popular choice amongst developers who build high-performance games or plan on doing entry-level SDK work. Some employers seek out Android developers that can create multiple platforms at the same time using programming frameworks like Flutter or React Native. If you are working with Flutter, you will also need to know Dart. If you are working with React Native, you will most likely also need JavaScript programming knowledge.