Android Development Cheat Sheet 2026

The 30 highest-yield Android Development facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which of the following languages is the basis for Android? → JAVA
2. How do you specify Constraints for a WorkManager WorkRequest? → Using the Constraints.Builder class
3. What annotation marks a class as a Room database entity? → @Entity
4. What method must be overridden to provide views in a RecyclerView.Adapter? → onCreateViewHolder
5. Which coroutine builder launches a new coroutine and returns a Job? → launch
6. What does APK size optimization technique 'code shrinking' do via R8 or ProGuard? → Removes unused classes, fields, methods, and attributes from the compiled output
7. Which operating system serves as the Android stack's base? → Linux
8. When using DiffUtil with RecyclerView, what is the main performance advantage over calling notifyDataSetChanged()? → It calculates the minimal set of changes and animates only affected items
9. Which DataStore type stores typed objects using Protocol Buffers? → Proto DataStore
10. What method inflates a layout resource in Android? → Both A and B
11. What is the recommended way to run Room database operations off the main thread? → Using Kotlin coroutines with suspend functions
12. How do you perform a database migration in Room when the schema changes? → By providing a Migration object with SQL migration scripts
13. When using Room database, what should you avoid doing on the main thread to prevent ANR errors? → Running database queries synchronously
14. Which of the following is the Android database? → SQLite
15. Which of the three basic components of an.apk file is not one of these? → Webkit
16. Which file access mode should be used to append data to a file in Android? → MODE_APPEND
17. The method can be used to stop an activity. → finish()
18. Which attribute controls the visibility of a view in Android XML? → android:visibility
19. Which SQL clause is used in a Room @Query to filter results? → WHERE
20. Which Jetpack component is the recommended replacement for SharedPreferences? → DataStore
21. What is the purpose of the android:exported attribute in AndroidManifest.xml? → To control whether other apps can access the component
22. What is the purpose of the Truth assertion library in Android testing? → To provide fluent, readable assertion methods as an alternative to JUnit assertions
23. The Content Provider is turned on by . → Using Content Resolver
24. Which testing approach tests multiple integrated components together? → Integration testing
25. What is the purpose of the include tag in Android XML layouts? → To reuse a layout file inside another layout
26. What is the recommended way to load large bitmaps efficiently to avoid OutOfMemoryError in Android? → Use BitmapFactory.Options to subsample the bitmap before decoding
27. Which ConstraintLayout feature allows multiple views to be evenly spaced using a chain? → Chain style
28. What is the purpose of the EncryptedSharedPreferences in Android? → To encrypt both keys and values stored in SharedPreferences
29. What is the activity's parent class? → ContextTheme Wrapper
30. You'll need an AVD to make an emulator. What exactly does it mean? → Android Virtual Device