Flutter Object-Oriented Programming: Understanding the Differences between ‘extends,’ ‘implements,’ and ‘with’

Differences between ‘extends,’ ‘implements,’ and ‘with’

When working with object-oriented programming in Flutter, you may come across two keywords: “extends” and “implements.” Both of these keywords have specific meanings and uses, and it’s essential to understand the differences between them to make the most of your code.

In this blog post, we’ll explore the difference between “extends” and “implements” in Flutter, how they are used, and when to use them.

What is “extends” in Flutter?

“Extends” is a keyword used to indicate that a class is inheriting from another class. In Flutter, inheritance is a way to create a new class that is a variation of an existing class. The new class, known as the child class, inherits all the properties and methods of the parent class, known as the superclass, and can also add new properties and methods or override existing ones.

Here’s an example of how “extends” is used in Flutter:

class Animal {

String name;

void makeSound() {

print(“Animal sound”);}}

class Dog extends Animal {

void makeSound() {

 print(“Bark”);}}

In this example, the “Dog” class extends the “Animal” class. The “Dog” class inherits the “name” property and “makeSound” method from the “Animal” class but overrides the “makeSound” method to print “Bark” instead of “Animal sound.”

What is “implements” in Flutter?

“Implements” is a keyword used to indicate that a class is implementing an interface. An interface is a set of method signatures that a class must implement. In Flutter, interfaces are used to define a contract that a class must follow.

Here’s an example of how “implements” is used in Flutter:

abstract class Animal {

void makeSound();

}

class Dog implements Animal {

void makeSound() {

print(“Bark”);

}

}

In this example, the “Dog” class implements the “Animal” interface. The “Animal” interface defines the “makeSound” method, which the “Dog” class must implement. In this case, the “Dog” class implements the “makeSound” method to print “Bark.”

When to use “extends” and “implements” in Flutter?

Use “extends” when you want to create a new class that inherits properties and methods from an existing class and can add new properties and methods or override existing ones. Use “implements” when you want to define a contract that a class must follow, such as implementing a set of method signatures.

In general, inheritance is used to create a hierarchy of classes, where each class inherits properties and methods from a parent class, while interfaces are used to define a set of method signatures that a class must implement.

What is a mixin in Flutter?