Define interface for variables #dart

main.dart

void main() {
  
  var obj = ConcreteClass("test");
 
  print(obj.myVariable);
}

class ConcreteClass extends AbstractClass {
  
  String myVariable;
  
  ConcreteClass(String myVariable) {
    this.myVariable = myVariable;
  }
}

abstract class AbstractClass {
 
  String get myVariable;
}