Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

Using the same function with different extended object types

Posted on 2011-03-07
2
Medium Priority
?
216 Views
Last Modified: 2012-05-11
Hi still being very green with Actionscript, I wonder if you could help with the following,

For the sake of an example think of a page in a book where,

I have 4 seperate classes,  ParagraphData, PartHeadingData, FooterData and ListData each which extend from the PageItemData class, a pageItem being its namesake on a page and each class has a different set of extended properties

Each "page of the book" as such is presented in an array called pageData and contains for example 3 instances of ParagraphData, 1 PartHeadingData , 1 list etc
 
What I need to do is iterate over the pageData array and act accordingly depending on what object type is currently being examined.

I have tried the following but with no success.

for each (var pageItem:PageItemData in pageData){
                        
      //check for prefix span and add if true            
                        if (pageItem.has_Prefix_Span && pageItem.prefix_Span_Text!==""){
                              createParagraphPrefixSpan(pageItem,pElem)
                        }
                              
      //check for inline graphic      
                        if ((pageItem.paragraph_Contains_Figure)as ParagraphData){
                        pElem=figure.checkForFigure(pageItem,pElem,figureData);
                        }

The first portion works because of the properties within the PageItemData class which are common to all , but the second does not ,even if I try to cast to the correct datatype, the compiler keeps complaining about


1118: Implicit coercion of a value with static type vo:PageItemData to a possibly unrelated type vo:ParagraphData

1119: Access of possibly undefined property paragraph_Contains_Figure through a reference with static type vo:PageItemData

I know I could replace the first line with

for each (var pageItem:* in pageData){

but this seems odd to me seing as all the items being iterated over are extended from the type shown.

What am I missing here and thanks in advance

John


}
0
Comment
Question by:BloodGrinder
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 20

Accepted Solution

by:
ChristoferDutz earned 2000 total points
ID: 35056986
Well I'd to some checks the following way:
if(pageItem is ParagraphData) {
   var paragraphData:ParagraphData = ParagraphData(pageItem);

   ... work with paragraphData ...

} 

Open in new window


In the if-part you check if the type is the one you expect.
If it is I tend to define a local varialbe containing a casted reference to the type I did my check for. This makes working with it a lot easier.

By the way ... I wouldn't write "!==" ... I think you are looking for "!=" (Actually I don't know what !== actually does think it's a check for instance equality)
0
 

Author Closing Comment

by:BloodGrinder
ID: 35113072
Apologies I thought i had closed this 3 days ago
0

Featured Post

VIDEO: THE CONCERTO CLOUD FOR HEALTHCARE

Modern healthcare requires a modern cloud. View this brief video to understand how the Concerto Cloud for Healthcare can help your organization.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This is intended to introduce all collision detection principles in flash, their strengths, weaknesses and workarounds. The main method for Collision Detection in flash is using hitTestObject. But unless you'll be pushing rectangular shapes without …
Sometimes you know that one object has a specific child in it, but you can't find the child. This happened to me when I was trying to code some actionScript to make a toolbar work with its embedded buttons.  My partner had created the toolbar usi…
In this tutorial viewers will learn how to create a basic motion tween animation in Flash Open a new document in Flash: Draw/import an image: Press CTRL + F8 to convert it into a graphic symbol: Select a frame (how long you want the tween to last): …
The goal of the tutorial is to teach the user how to set there setting in Adobe Flash Media Live Encoder and YouTube for optimal video and audio quality.
Suggested Courses

705 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question