在 Dart 中将类类型作为变量传递

Question

It is possible to pass a class type as a variable in Dart ?

I am trying to do something as follows:

class Dodo
{
  void hello() {
    print("hello dodo");
  }
}

void main() {

var a = Dodo;
var b = new a();
b.hello();

}

in python similar code would work just fine. In Dart I get an error at new a() complaining that a is not a type.

Is is possible to use class objects as variables ? If not, what is the recommended work around ?

Answer 1

ANother way to do it is by passing a closure rather than the class. Then you can avoid using mirrors. eg

a = () => new Dodo();
...
var dodo = a();

Answer 2

You can use the mirrors api:

import 'dart:mirrors';

class Dodo {
  void hello() {
    print("hello dodo");
  }
}

void main() {
  var dodo = reflectClass(Dodo);

  var b = dodo.newInstance(new Symbol(''), []).reflectee;
  b.hello();
}

Maybe it can be written more compact, especially the new Symbol('') expression.

Answer 3

what you can do is :

const dynamic a = Dodo; // or dynamic a = Dodo;
var b = new a();
b.hello();

This works fine for me; enjoy!