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. Which statement about App Bundles (.aab) versus APKs is correct? → Play generates optimized per-device APKs from the bundle, reducing download size
7. What does APK size optimization technique 'code shrinking' do via R8 or ProGuard? → Removes unused classes, fields, methods, and attributes from the compiled output
8. Which operating system serves as the Android stack's base? → Linux
9. A developer needs to run a task that must complete even if the user closes the app, such as uploading logs nightly. Which API is the recommended choice? → WorkManager
10. 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
11. In Jetpack Compose, what happens when a State object read inside a composable changes its value? → The composable that reads it is scheduled for recomposition
12. Which DataStore type stores typed objects using Protocol Buffers? → Proto DataStore
13. What method inflates a layout resource in Android? → Both A and B
14. What is the recommended way to run Room database operations off the main thread? → Using Kotlin coroutines with suspend functions
15. How do you perform a database migration in Room when the schema changes? → By providing a Migration object with SQL migration scripts
16. When using Room database, what should you avoid doing on the main thread to prevent ANR errors? → Running database queries synchronously
17. Which of the following is the Android database? → SQLite
18. Which of the three basic components of an.apk file is not one of these? → Webkit
19. Which file access mode should be used to append data to a file in Android? → MODE_APPEND
20. The method can be used to stop an activity. → finish()
21. Which attribute controls the visibility of a view in Android XML? → android:visibility
22. Which SQL clause is used in a Room @Query to filter results? → WHERE
23. Which Jetpack component is the recommended replacement for SharedPreferences? → DataStore
24. What is the purpose of the android:exported attribute in AndroidManifest.xml? → To control whether other apps can access the component
25. What is the purpose of the Truth assertion library in Android testing? → To provide fluent, readable assertion methods as an alternative to JUnit assertions
26. The Content Provider is turned on by . → Using Content Resolver
27. Which testing approach tests multiple integrated components together? → Integration testing
28. What is the purpose of the include tag in Android XML layouts? → To reuse a layout file inside another layout
29. What is the recommended way to load large bitmaps efficiently to avoid OutOfMemoryError in Android? → Use BitmapFactory.Options to subsample the bitmap before decoding
30. Which ConstraintLayout feature allows multiple views to be evenly spaced using a chain? → Chain style