Missing concrete implementation of Getter and Setter

Question

class Shape {
  String color;

  void draw() {
    print('Draw Random Shape');
  }
}

class Rectangle implements Shape {

  @override
    void draw() {
      print('Draw Rectangle');
    }
}

Now the problem is I'm getting a warning saying

Missing concrete implementation of getter Shape.color and setter Shape.color

I know that every instance variable in dart has its own getter and setter implicitly.But in case of interface how do I fix this issue.I have also tried to looking at some of the similar questions on the stackoverflow but they'r not helpful.

Answer 1

Dart doesn't inherit implementations from implements Shape, but only states that Rectangle conforms the interface of Shape.

You need to add String color; to Rectangle to satisfy implements Shape.
You can do this by adding a field or alternatively a getter and a setter. Both are equivalent from a class' interface perspective.

class Rectangle implements Shape {
  String color;

  @override
    void draw() {
      print('Draw Rectangle');
    }
}

or

class Rectangle implements Shape {
  String _color;

  String get color => _color;
  set color(String value) => _color = value;

  @override
    void draw() {
      print('Draw Rectangle');
    }
}

The later is considered bad style if the getter and the setter only forward to a private field with no additional code.

Answer 2

or maybe you just want to extends , no need to implements ?

you can changes your code into this ?

import 'package:meta/meta.dart';


abstract class Shape {
  String color;

  Shape({
    @required this.color 
  });

  void draw() {
    print('Draw Random Shape');
  }
}

class Rectangle extends Shape {
  Rectangle() : super(
    color: "#ff00ff"
  );

  @override
    void draw() {
      print('Draw Rectangle');
    }
}

hope that can help