Everything in Mobile Dev, page 67
Kotlin Scope Functions: Cleaner Code, Clearer Choices
Kotlin's scope functions (let, run, apply) create a temporary workspace for an object, avoiding repetitive variable names. Use them for object configuration or chaining calls.
Kotlin Extension Functions: Add Methods Without Inheritance
Kotlin extension functions let you add new functionality to existing classes without inheritance, as if you were adding a new method. They're perfect for creating helpers for third-party library classes or framework types like String.
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.
Kotlin Functions: Named, Reusable Code Blocks
A function is a named recipe for your code. You give it ingredients (parameters) and it produces a result. They are used everywhere, from calculating values to handling button clicks.
Kotlin Null Safety: Catch Nulls at Compile Time
Kotlin's type system catches null pointer errors at compile time. Variables are non-nullable by default; you must opt-in to nulls with a ? (e.g., String?). The compiler then forces you to handle the null case. The main footgun is the !! operator.
Kotlin Variables: `val` for Constants, `var` for Variables
In Kotlin, val creates a read-only constant you assign once, like a fixed setting. var creates a mutable variable you can change later. Always prefer val unless you explicitly need to reassign a value to prevent accidental state changes.
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