Book Image

DART Cookbook

By : Ivo Balbaert
Book Image

DART Cookbook

By: Ivo Balbaert

Overview of this book

Table of Contents (18 chapters)
Dart Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Using the call method


This is a hidden gem in Dart. It enables you to give a parameter to an object, thereby invoking the call method from the object's class.

How to do it...

See its usage in the call project, as shown in the following code:

var u = "Julia";

void main() {
  var embr = new Embrace(5);

The call method can be used in the following ways:

  1. Invoke call, as shown in the following code:

      embr(u); // callable method!
      var m = new Mult();
      print(m(3, 4));
    }
    
    class Embrace {
      // see code in recipe: Using reflection
  2. Define the call method, as shown in the following code:

      call(var user) { print("$user is called, and hugged with strength $strength!"); }
     }
    
    class Mult{
      call(int a, int b) => a * b;
    }

We get the following output on the screen:

Julia is called, and hugged with strength 5!

12

How it works...

We pass the value u to the embr object in the embr(u) call, which invokes the call method. This method defines what the instances of your class do when invoked as functions via the...