Intermediate everything in Mobile Dev, page 35
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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