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To extend the functionality of an already implemented class in Android (Java/Kotlin), several methods can be used:
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Inheritance — create a subclass that extends the base class and adds or overrides methods.
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Composition — include an instance of an existing class in a new class and delegate calls, adding new logic.
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Decorator — wrap an object in another object that adds functionality while preserving the interface.
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Extension Functions (in Kotlin) — add new functions to existing classes without inheritance.
Java example of inheritance:
public class BaseClass {
public void doSomething() {
System.out.println("Base implementation");
}
}
public class ExtendedClass extends BaseClass {
@Override
public void doSomething() {
super.doSomething();
System.out.println("Extended functionality");
}
}
Kotlin extension function example:
fun String.addExclamation(): String {
return this + "!"
}
val greeting = "Hello".addExclamation() // "Hello!"
The method choice depends on the specific task and project constraints.