Dart| Flutter How to: Find an object implements interface

In Dart, Class extends only one parent class and implements multiple interfaces.

Below are operators to check a class of a given object.

is checks a given object implements or extends interface or class, It checks parent class hierarchy and returns true if it follows inheritance. runtimeType: Returns the class of an object and gives the only current class of an object not the inheritance tree class

#checking if an object implements interface in dart?

This example checks an object and implements interfaces.

In this example, Created two interfaces Shape and Shape1.

Create a Square class that implements Multiple interfaces(Shape,Shape1) Create a Circle that implements the single interface(Shape)

use the is operator in Dart to check whether an object implements a particular interface or not.

Here is an example program

void main() {
  var square = new Square();
  var circle = new Circle();

  print(square is Shape); //true
  print(square is Shape1); //true
  print(square.runtimeType); //Square

  print(circle is Shape); //true
  print(circle.runtimeType); //Circle
}

abstract class Shape {
  void display() {
    print("Shape");
  }
}

abstract class Shape1 {
  void display() {
    print("Shape");
  }
}

class Circle implements Shape {
  void display() {
    print("Circle");
  }
}

class Square implements Shape, Shape1 {
  void display() {
    print("Square");
  }
}

Output:

true
true
Square
true
Circle

#How to check Object extends class in dart?

This checks if a given object extends the class or not.

In this example, Created two interfaces Animal and Animal.

Create a Lion class that implements Class(Animal), Since the implicit class is an interface in dart. Create a Cat that extends a single interface(Animal)

use the is operator in Dart to check whether an object extends a particular class or not.

Here is an example program

void main() {
  var lion = new Lion();
  var cat = new Cat();

  print(lion is Animal); //true
  print(lion is Animal1); //false
  print(lion.runtimeType); //Lion

  print(cat is Lion); //true
  print(cat.runtimeType); //Cat
}

class Animal {
  void display() {
    print("Animal");
  }
}

class Animal1 {
  void display() {
    print("Shape");
  }
}

class Lion implements Animal {
  void display() {
    print("Lion");
  }
}

class Cat extends Animal1 {
  void display() {
    print("Cat");
  }
}