Intermediate everything in Mobile Dev, page 35
Android Build Variants: One Codebase, Many Apps
Think of build variants as a matrix for your app builds, combining build types (like debug/release) with product flavors (like free/paid). This lets you manage different API endpoints or features for various versions from a single codebase.
Adding Build Dependencies with Gradle in Android
Gradle is the tool for adding build dependencies to your Android app. This allows you to integrate external libraries like Jetpack, Compose, or Google Play Services, which are essential for building modern applications.
Kotlin Delegated Properties: Reusing Getter/Setter Logic
Kotlin's delegated properties let you outsource a property's getter/setter logic. Instead of writing boilerplate, you reuse common patterns like lazy initialization (by lazy) or observing changes (by observable).
StateFlow: A Hot Flow for UI State
StateFlow is a state-holder observable that emits the current and new state updates to its collectors. Use it to expose UI state from a ViewModel to a UI. The footgun: slow collectors can miss intermediate state updates, receiving only the most recent value.
Kotlin Coroutines: async/await for Parallel Results
async starts a coroutine for a parallel result, returning a Deferred value. await pauses until that result is ready. Use it to run independent network calls concurrently. The footgun: using it for sequential tasks creates a needless race condition.
Structured Concurrency in Kotlin
Structured concurrency treats async operations like code blocks: a parent task's lifetime contains its children. In Kotlin, a CoroutineScope ensures if the parent is cancelled, all its child coroutines are too.
Kotlin Data Classes: Automatic Boilerplate for Data Holders
A Kotlin data class automatically generates boilerplate like equals() and toString() for classes that just hold data. Use it for model objects or DTOs where value equality matters. The footgun: its copy() method is shallow, sharing mutable objects.
Kotlin Inheritance: Open for Extension, Closed by Default
In Kotlin, classes are final by default. Think of inheritance as an opt-in feature you enable with the open keyword. Use it to create specialized versions of a base class, like a Student from a Person.
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