Flutter Dart - 动态获取类的属性

Question

I would like to get the property of a class by passing a String name. How can I do that?

class A {
  String fName ='Hello';
}

main() {
A a = A();
String var1='fName'; // name of property of A class

print (a.fName); // it is working fine

print (a.$var1); // it is giving error that no getter in A class. but I want to pass var1 and automatically get the associate property

}

Answer 1

Further to Suman's answer I recommend exposing a method that converts the object to a map and retrieves the property if it's there.

For example:

class Person {
  String name;
  int age;

  Person({this.age, this.name});

  Map<String, dynamic> _toMap() {
    return {
      'name': name,
      'age': age,
    };
  }

  dynamic get(String propertyName) {
    var _mapRep = _toMap();
    if (_mapRep.containsKey(propertyName)) {
      return _mapRep[propertyName];
    }
    throw ArgumentError('propery not found');
  }
}

main() {
  Person person = Person(age: 10, name: 'Bob');

  print(person.name); // 'Bob'

  print(person.get('name')); // 'Bob'
  print(person.get('age')); // 10

  // wrong property name
  print(person.get('wrong')); // throws error
}

Answer 2

A quick workaround would be,

1. Convert your class into JSON.
2. Access the property via json[key].

void main() {
  String var1='name';
  String var2='age';
  Info info= Info(name:"Suman", age:4);
  final json=info.toJson();
  print("NAME = ${json[var1]}");
  print("AGE = ${json[var2]}");
}

class Info {
  String name;
  int age;

  Info({this.name, this.age});

  Info.fromJson(Map<String, dynamic> json) {
    name = json['name'];
    age = json['age'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['name'] = this.name;
    data['age'] = this.age;
    return data;
  }
}

Hope this helps. Cheers.