Webmaster Forum / Flash / Flash Actionscript / July 2008

well using the methods you've indicated, you haven't exactly 'store' the
questions within the array 'list' as the array will only contain a single index
housing the xml doc.  a more common way to do this is to iterate through the
xml within the onload handler and assign each node value to a new index within
the array.  if each 'question' node also contains the 'answer' you may wish to
create an Object that contains both q and a an then store those Objects at each
index in the array.  in this way you can advance through the array simply by
changing/tracking the current index.  a bit more like this:

(ps. I'm not certain of the xml paths in your doc - i would need to see the
xml structure to be certain)

var quiz = [ ];
var index = 0;

var xml = new XML();
xml.ignoreWhite = true;
xml.onLoad = function() {
  for(var i=0; i<this.firstChild.childNodes.length; i++) {
    quiz.push( {q:this.firstChild.childNodes[i].childNodes[0].firstChild,
a:this.firstChild.childNodes[i].childNodes[1].firstChild});
  }
}
xml.load('questions.xml');

function display() {
  txt_question.text = quiz[index].q;
}

nextBtn.onPress = function() {
  if(index<quiz.length-1) index++;
  display();
}

I'm learning Action Script 2.0 and my instructions are as follows (I want you
to get the whole picture.

Flash Questionnaire Progam, Version 1: Technical Specs
This document outlines the technical specifications for a Flash?based
questionnaire program. This program allows users to take a timed test, after
which they are given a summary indicating their score. The program is intended
for deployment as a desktop application (.exe).
Program Flow
Loading Screen
When the program is first opened it should display a startup screen while it
loads an external XML document containing a list of questions and answers. When
the XML document has been loaded and parsed, a ?Start? button should be
displayed that takes the user to the Instructions screen.
Instructions Screen
The instructions screen displays some general instructions to the user about
how to use the survey. It should tell them that they will be timed, and how to
answer the questions. This screen should contain a button that says ?Start the
Survey?, which will take the user into the Questionnaire.
The Questionnaire
This is the main part of the application. Each question in the XML document
should be displayed, one at a time, along with the answers. When a user clicks
an answer, their selection should be recorded, and the next question should be
displayed.
A timer should be running during the course of the questionnaire. This should
count down, and when it reaches 0 the questionnaire portion of the application
should end, and the user should be taken to the Summary screen.
Summary Screen
The summary screen should tell the user how many answers they answered
correctly, and how many they answered incorrectly. There should also be a
button allowing the user to re?take the questionnaire. Clicking this button
should go back to the Instructions screen.
Technical Overview
XML Structure
The XML document containing the questions should be structured as follows:
<questions>
<question>
<text>This is the text of the question.</text>
<answers>
<answer correct=?true?>This is the first option</answer>
<answer>This is the second option</answer>
<answer>This is the third option</answer>
</answers>
</question>
</questions>
The <questions> node may contain multiple <question> nodes, and the <answers>
node should contain one or more <answer> nodes.
The XML file should be parsed into Flash using the XPath API. Information
about the XPath API has been included with this delivery. A sample file has
also been included that demonstrates how to use the XPath API.
Questionnaire Elements
The questionnaire should be composed of a dynamic text field for displaying
the question, and multiple instances of an ?answer? movieclip for displaying
the answers. The answer movieclip should contain a dynamic text field for
displaying the answers, and a button that allows users to select that answer.

help using the XPath class

1
XPathAPI class
ActionScript Class Name mx.xpath.XPathAPI
The XPathAPI class allows you to do simple XPath searches within Macromedia
Flash. This
can be very useful for searching XML packets based on node names and attribute
values. In
other words, you can quickly find nodes and attributes in an XML document
using the
XpathAPI methods.
To do XPath searches within Flash, you must first include the XPathAPI class
in your Flash
library by adding the DataBindingClasses component(if it hasn't been added
already). If
you?ve already set up bindings, this class may have been included
automatically; otherwise,
you must select the class from the common libraries (Window > Common Libraries

Classes). From the Classes.fla library panel, you can drag a copy of the
DataBindingClasses
component into your current Flash document?s library. You then import the
XPathAPI class
by typing import mx.xpath.XPathAPI, or by using the class?s fully qualified
class name as a
prefix when accessing the class methods (mx.xpath.XPathAPI.method_name).
Flash supports the following path expressions:
Type Example
Absolute path /item/title
Relative path title if the context node is <item>
wildcard (*) /*/title retrieves all <title> elements,
whatever the parent node is
predicate expressions using =, AND, or OR /item/title[@version='current']
or:
/item/title[@version='current' AND
@post='today']
2 XPathAPI class
Method summary for the XPathAPI class
The following table lists the available methods of the XPathAPI class.
XPathAPI.getEvalString()
Availability
Flash Player 6 (6.0.79.0).
Edition
Flash MX 2004.
Usage
XPathAPI.getEvalString(node, path)
Parameters
node An XML node; a reference to the DOM node that is the parent node from
which the
statement executes.
path A string identifying the path through the XML node hierarchy.
Returns
A string that represents the code required to access the value specified by
the path parameter
from the parent node.
Description
Method; for a specified node, gets the corresponding evaluation string.
Method Description
XPathAPI.getEvalString() For a specified node, gets the corresponding
evaluation string.
XPathAPI.selectNodeList() Retrieves all the node values of a specified node
level.
XPathAPI.selectSingleNode() Retrieves the node value of the first node at a
specified node level.
XPathAPI.setNodeValue() Sets the value of a specified node or attribute.
XPathAPI.selectNodeList() 3
Example
The following example displays the corresponding evaluation string used for a
specified node
in the Output panel:
import mx.xpath.XPathAPI;
var rssfeed_xml:XML = new XML();
rssfeed_xml.ignoreWhite = true;
rssfeed_xml.onLoad = function(success:Boolean) {
trace("onload...");
if (success) {
trace("success...");
// Retrieve all title notes within /rss/channel/item.
var thePath_str:String = "/rss/channel/item";
// Get the evaluation string used for the search.
var myEvalString_str:String = XPathAPI.getEvalString(this.firstChild,
thePath_str);
trace("getEvalString: " + myEvalString_str);
} else {
trace("error loading XML");
}
};
rssfeed_xml.load("http://www.flash-mx.com/news/index.xml");
XPathAPI.selectNodeList()
Availability
Flash Player 6 (6.0.79.0).
Edition
Flash MX 2004.
Usage
XPathAPI.selectNodeList(node, path)
Parameters
node An XML node; a reference to the DOM node that is the parent node from
which the
statement executes.
path A string identifying the path through the XML node hierarchy.
Returns
An array of nodes matching the given XPathAPI statement.
Description
Method; retrieves all the node values of a specified node level.
4 XPathAPI class
Example
The following example stores all the title node values into an array, and then
displays the list
in the Output panel:
import mx.xpath.XPathAPI;
var rssfeed_xml:XML = new XML();
rssfeed_xml.ignoreWhite = true;
rssfeed_xml.onLoad = function(success:Boolean) {
trace("onload...");
if (success) {
trace("success...");
// Retrieve all title notes within /rdf:RDF/item/title.
var thePath_str:String = "/rdf:RDF/item/title";
var title_array:Array = XPathAPI.selectNodeList(this.firstChild,
thePath_str);
for (var i:Number = 0; i < title_array.length; i++) {
trace(title_array[i].firstChild.nodeValue);
}
} else {
trace("error loading XML");
}
};
rssfeed_xml.load("http://weblogs.macromedia.com/dev_center/index.rdf");
XPathAPI.selectSingleNode()
Availability
Flash Player 6 (6.0.79.0).
Edition
Flash MX 2004.
Usage
XPathAPI.selectSingleNode(node, path)
Parameters
node An XML node; a reference to the DOM node that is the parent node from
which the
statement executes.
path A string identifying the path through the XML node hierarchy.
Returns
The XML node found for the specified path and node, or null if not found.
XPathAPI.setNodeValue() 5
Description
Method; returns a single node from the given node and XPath parameters. If the
path
specified will result in multiple nodes returned, this method will return only
the first one
found.
Example
The following example finds the first title node value within the item node,
and then displays
the value in the Output panel:
import mx.xpath.XPathAPI;
var rssfeed_xml:XML = new XML();
rssfeed_xml.ignoreWhite = true;
rssfeed_xml.onLoad = function(success:Boolean) {
trace("onload...");
if (success) {
trace("success...");
// Retrieve first title node within /rdf:RDF/item/title.
var thePath_str:String = "/rdf:RDF/item/title";
var titleNode_str:String = XPathAPI.selectSingleNode(this.firstChild,
thePath_str);
trace(titleNode_str.toString());
} else {
trace("error loading XML");
}
};
rssfeed_xml.load("http://weblogs.macromedia.com/dev_center/index.rdf");
XPathAPI.setNodeValue()
Availability
Flash Player 6 (6.0.79.0).
Edition
Flash MX 2004.
Usage
XPathAPI.setNodeValue(node, path, newValue)
Parameters
node An XML node; a reference to the DOM node that is the parent node from
which the
statement executes.
path A string identifying the path through the XML node hierarchy.
newValue A string containing the new value for the node or attribute.
6 XPathAPI class
Returns
The number of nodes updated.
Description
Method; sets the value of the node or attribute identified in the path string
to the value of the
newValue parameter.
Example
The following example changes the node values for the specified node path, and
then displays
a summary of the changes in the Output panel:
import mx.xpath.XPathAPI;
var rssfeed_xml:XML = new XML();
rssfeed_xml.ignoreWhite = true;
rssfeed_xml.onLoad = function(success:Boolean) {
trace("onload...");
//trace(rssfeed_xml);
if (success) {
var i:Number;
// Retrieve all title notes within /rss/channel/item.
var thePath_str:String = "/rss/channel/item/dc:creator";
var creator_array:Array = XPathAPI.selectNodeList(this.firstChild,
thePath_str);
trace("before:");
for (i = 0; i < creator_array.length; i++) {
trace("\t" + i + ". " + creator_array[i].firstChild.nodeValue);
}
var updatedNodes_num:Number = XPathAPI.setNodeValue(this.firstChild,
thePath_str, "dave");
trace(" ***** " + updatedNodes_num + " nodes updated ***** ");
var creator_array:Array = XPathAPI.selectNodeList(this.firstChild,
thePath_str);
trace("after:");
for (i = 0; i < creator_array.length; i++) {
trace("\t" + i + ". " + creator_array[i].firstChild.nodeValue);
}
} else {
trace("error loading XML");
}
};
rssfeed_xml.load("http://www.flash-mx.com/news/index.xml");