참고용 자료 : Android 개발자 기초(JAVA)
라이브러리 정리 : Library
Lesson 1 : Build your first app
1.1 Android Studio and Hello World
Lesson 2 : Activities and intents
Lesson 3 : Testing, debugging, and using support libraries
Lesson 4 : User interaction
Lesson 5 : Delightful use experience
Lesson 7 : Background tasks
Lesson 8 : Alarms and scheduler
Lesson 9 : Preferences and settings