ActionScript for Flash MX: The Definitive Guide, Second Edition

Function.call() Method

This is the Title of the Book, eMatter Edition

Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.

Alphabetical Language Reference

|

531

// Store extra arguments. We'll pass them to meth later.

this.args = arguments.slice(3);

// Set an empty intervalID. Used with setInterval().

this.intervalID = -1;

// Start the countdown

this.start();

}

/*

* Method: start()

*/

CountDown.prototype.start = function () {

// Invoke the method-caller after this.delay milliseconds.

this.intervalID = setInterval(this, "invokeCallback", this.delay);

};

/*

* Method: stop()

*/

CountDown.prototype.stop = function () {

// Stop the interval so that it doesn't call the method again.

clearInterval(this.intervalID);

this.intervalID = -1;

};

/*

* Method: invokeCallback()

*/

CountDown.prototype.invokeCallback = function () {

// Time's up! Stop the countdown.

this.stop();

// Invoke the callback as a method of this.obj, and pass

// along this.args to use as method arguments.

this.callback.apply(this.obj, this.args);

};

// SAMPLE USE

// Create the countdown. Will invoke

// _root.output("hello", "world") after 1000 milliseconds.

count = new CountDown(_root, "output", 1000, "hello", "world");

// The method to invoke

function output (arg1, arg2) {

trace("output: " + arg1 + ", " + arg2);

}

See Also

Function.call(), the Arguments object; Chapter 12

Function.call() Method

invoke a function as an object method ...