Tauseef FayyazA to Z
Glossary
Every concept in this sheet, plus the smaller terms it uses. Select a concept to open its card.
C
- Collections and their operations
- Kotlin separates read-only
List,SetandMapfromMutableListand friends, and offers functions such asmap,filter,groupBy,associateByandsumOf. - Coroutines and suspend functions
- A
suspendfunction can pause without blocking a thread.
D
- Data classes
- A
data classgeneratesequals,hashCode,toString,copyand destructuring from its constructor properties. - Declarative UI
- You describe what the screen should look like for the current state, and the framework works out what to change on screen.
- Dispatchers and withContext
- A dispatcher decides which threads a coroutine runs on:
Dispatchers.Mainfor UI,Dispatchers.IOfor blocking I/O andDispatchers.Defaultfor CPU work.
F
- Flow and StateFlow
- A
Flowis a cold stream of values produced by a suspend block and read withcollect. - Functions, lambdas and extensions
- Functions support default and named arguments.
G
- Gradle and version catalogs
- Gradle builds Android apps.
H
- Hot reload and previews
- Tools that show code changes in a running app or an editor preview within a second or two, without rebuilding the whole app.
L
- Lazy lists
- A lazy list only builds the rows currently on screen, plus a few ahead, and recycles them as you scroll.
M
- Modifiers
- A
Modifieris an ordered chain that decorates a composable with size, padding, background, click handling, semantics and more.
N
- Null safety
- Types are non-null by default;
String?may be null.
P
- Platform design guidelines
- Material Design 3 is Google's design system for Android, and the Human Interface Guidelines are Apple's rules for iOS.
R
- Recomposition and side effects
- When state a composable reads changes, Compose runs that composable again (recomposition).
- Rows, columns and stacks
- The basic layout containers place children horizontally, vertically or on top of each other, with spacing and alignment options.
S
- Safe areas and screen sizes
- Safe areas, or insets, are the parts of the screen not covered by the notch, status bar, camera cutout or gesture bar.
- Sealed classes and when
- A
sealedclass or interface has a fixed set of subtypes known at compile time.
T
- Text input and forms
- A text field shows a value from state and reports every change back.
- Theming and dark mode
- A theme defines colours, typography and shapes in one place.
V
- val, var and type inference
valis a read-only reference,varcan be reassigned, and the compiler infers types when they are obvious.