I am trying to make a basic input calculator for class, but I am constantly encountering problems when I solve the old one.
Here is what I have so far:
var answer
import flash.events.MouseEvent;
plus.addEventListener(MouseEvent.CLICK,aaa);
function aaa(e:MouseEvent)
{
var a:Number = Number(input1.text) + Number(input2.text)
a.text = String(a);
}
The problem that I am having right now is 1119:Access of possibly undefined property undefined property text through a reference with static type Number
For starters, the line you declare the variable a has no semicolon:
var a:Number = Number(input1.text) + Number(input2.text) // missing semicolon
Secondly, you define a to be a Number. The data type Number only has public methods and constants, not public variables, and none of its methods are text. Thus a.text gives you the error. AS3 - Number Reference
Thirdly, the Number data type has a method called toString. Therefore, simply call a.toString() instead of String(a).
Lastly, if I knew what you were trying to do I would provide insight.
Update
Try the following code out and let me know in the comments how it turns out.
import flash.events.MouseEvent; // handle imports before anything else
var answer:String = ""; // holds the result of the addition as a String
// add a mouse click handler to the 'plus' object
plus.addEventListener(MouseEvent.CLICK, plusOnClick);
// 'plusOnClick' is the 'plus' object's mouse click handler
function plusOnClick(e:MouseEvent)
{
// 'result' is used to hold the result of the addition as a Number
var result:Number = Number(input1.text) + Number(input2.text)
// set 'answer' to the String representation of 'result'
answer = result.toString();
trace("The result of the addition is " + answer);
}
Related
So, I have successfully grabbed a value out of an XML document and set it into a separate class called "AddCommas." The trace functions have shown me that it sets properly.
For more details, my objective is to take the language indicator ("fr" for french or "en" for english), set it inside the appropriate class and into a variable I will use. Now, I am using this variable to be used in an if statement; which will help me format a number properly (commas, decimals, spaces) per the clients request.
However, my problem is when I try to get the value to use it. It always comes back as Null. I have placed traces all over my program trying to pinpoint when this happens, but I cannot find it. Here's the code...
The pull from the XML file and into the set (this works fine, but I am adding it for your benefit in case I missed something)
public var commaHold = new AddCommas();
localLanguage = xmlObj.localLanguage;
trace("localLanguage + " + localLanguage);
commaHold.setLanguage(localLanguage); // Set Language
//More code follows...
This is the set function istelf...
public function setLanguage(localLanguage:String){
langHold = localLanguage;
trace("Set Language = " + langHold); //This always shows a successful set
}
Now am I wrong in thinking that in AS3, once langHold in my AddCommas class has been set I should be able to use it without calling a get within the function I am using the If Statement in, right? Such as this?
var language = langHold;
if (language == "en"){
trace("Language is = " + language); // More code follows afterwards and as of now, this shows NULL
Now, I have attempted plenty of Get functions to add the language variable in the call itself to this function and it's always the same. Am I missing some fundamentals here?
Thank you very much for your time.
If you expect a string comparison you need to use quotes, unless en is a String variable since langHold is a String, like:
if (language == "en"){
Consider modifying the set function to use the as3 keyword like:
private var _language:String;
public function set language(value:String):void {
_language = value;
//do other stuff here if necessary, put a breakpoint on the line above
}
public function get language():String{
return _language;
//put a breakpoint on the line above
}
You should be able to see when any instance of your class has the property changed. The only other issue I can think of is it is not the same instance of the class and therefore doesn't share the property value you set earlier. In the debugger you can check the "hashCode" or "address" it shows for this to see if it changes when it hits the breakpoints.
Here's a sample Singleton structure in AS3 (this all goes in one file):
package com.shaunhusain.singletonExample
{
public class SingletonExample
{
private static var instance:SingletonExample;
public static function getIntance():SingletonExample
{
if( instance == null ) instance = new SingletonExample( new SingletonEnforcer() );
return instance;
}
/**
*
* #param se Blocks creation of new managers instead use static method getInstance
*/
public function SingletonExample(se:SingletonEnforcer)
{
}
}
}
internal class SingletonEnforcer {public function SingletonEnforcer(){}}
using this single shared instance from any other class would look something like this:
private var singletonInstance:SingletonExample = SingletonExample.getInstance();
ShaunHusain's theory of using a Singleton was the perfect solution I needed. However, his code gave me a bizarre 1061 error and my format and code appeared to be error free. Regardless, I looked up another way to use a Singleton as follows that worked perfectly for me. Honestly, Shaun's code should work for anyone and I have no idea why it wasn't. I am perfectly willing to admit that it was probably a typo on my end that I just did not see.
I ended up embedding the Set and Get within the Singletons class and used it as an intermediary to hold the information I needed. It worked perfectly.
package chart {
import chart.*;
//
public class StaticInstance {
private static var instance:StaticInstance;
private static var allowInstantiation:Boolean;
private var language:String;
public static function getInstance():StaticInstance {
if (instance == null) {
allowInstantiation = true;
instance = new StaticInstance();
allowInstantiation = false;
}
return instance;
}
public function StaticInstance():void {
if (!allowInstantiation) {
throw new Error("Error: Instantiation failed: Use StaticInsance.getInstance() instead of new.");
}
}
public function setLanguage(_language:String):void{
language = _language;
trace("language set = " + language);
}
public function getLanguage():String{
return language;
}
}
}
This code allowed me to hold the data and call upon it again from two different classes. It's a very hack job instead of just being able to pass on the variable from function to function, but in my case we didn't create this file, we are modifying it and attempting to do things beyond the original scope of the project.
Thanks again for your help Shaun! I hope this helps other people!
Im trying to understan a function that I found on the web.
Iknow what the function does, It get the information about the webcam in your computer and post it on the textArea,
But the individual line are just a bit confused.
Any help ?
Thanks
private var camera:Camera;
private function list_change(evt:ListEvent):void {
var tList:List = evt.currentTarget as List;
var cameraName:String = tList.selectedIndex.toString();
camera = Camera.getCamera(cameraName);
textArea.text = ObjectUtil.toString(camera);
}
private var camera:Camera;
This line creates a variable of the class type Camera. It does not create an instance of the variable.
private function list_change(evt:ListEvent):void {
This line is a standard function heading. Because the argument is a ListEvent, it makes me think that this function is probably written as an event handler. Because of the name of the function, it is most like listening to the change event on a list.
var tList:List = evt.currentTarget as List;
This line creates a reference to the list that dispatched the event, which caused this handler to be executed.
var cameraName:String = tList.selectedIndex.toString();
This line converts the selectedIndex to a string. It's a bit odd to convert an index to a string, as opposed to some value. But the reason they do that looks to be on the next line..
camera = Camera.getCamera(cameraName);
This uses that camera variable (defined back in line 1) and actually gets an instance of the camera. It uses the "cameraName" which makes me think that the list that dispatched this change event contains a list of cameras available on the system.
textArea.text = ObjectUtil.toString(camera);
This converts the camera object to a string and displays it in a text area. Normally you wouldn't try to do this as it provides no valuable data. A default object will display strings as [Object object] or something similar. Perhaps the camera object has a custom string function; I don't have experience with that. Normally, you'd want to access properties of the object to get useful information, not try this on the object itself.
}
This line is the end of the function. The open bracket was in the 2nd line of code in the function definition.
I've got a block of code that's doing what I want - it generates a grid of MC's.
As soon as I put something like function blah() around it, it starts generating errors indicating lines of code I don't have e.g.
TypeError: Error #1010: A term is undefined and has no properties.
at flightCellMaker_fla::MainTimeline/myXMLtrace() [flightCellMaker_fla.MainTimeline::frame1:87]
at flightCellMaker_fla::MainTimeline/processFPBxml() [flightCellMaker_fla.MainTimeline::frame1:52]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at flash.net::URLLoader/onComplete()
When I take the function out, it does what I want it to do. What's up with that?
var testXML:XML;
var myFPBxml:XML;
// Initialise a URLLoader to get XML data from XML file
var myFPBLoader:URLLoader = new URLLoader();
myFPBLoader.load(new URLRequest("flightPlannerBoard.xml"));
// Check XML data fully loaded
myFPBLoader.addEventListener(Event.COMPLETE, processFPBxml);
// Once the flight board planning data is loaded, save it to a variable
function processFPBxml(e:Event):void {
myFPBxml = XML(e.target.data);
myXMLtrace();
}
// Grab the XML data load completed and make it available elsewhere
function myXMLtrace(){
testXML = XML(myFPBxml);
}
trace("***********************" + testXML.*); This throws an error (not within myXMLtrace tho)
OK, so here's the rest of the code that will run correctly on it's own but not in a function:
// Create and place all the flight cells for planning and drag and drop
// Setup 2 loops: j for columns and i for Rows
for (var j:Number =0; j < rowNum; j++){
for (var i:Number =0; i<9; i++){
// Create copies of flightCell for board grid
var my_mc = new flightCell();
my_mc.name = "mc"+i+j;
addChild(my_mc);
// Set event Listeners on all Child objects
my_mc.myDragShape.addEventListener(MouseEvent.MOUSE_OVER, fl_MouseOverHandler);
my_mc.myDragShape.addEventListener(MouseEvent.MOUSE_OUT, fl_MouseOutHandler);
my_mc.myDragShape.addEventListener(MouseEvent.MOUSE_DOWN, fl_MouseDownHandler);
my_mc.myDragShape.addEventListener(MouseEvent.MOUSE_UP, fl_MouseUpHandler);
Object(this).my_mc.yellowHiLite.visible = false;
//cellPos[j] = myXML.cellPosX[j];
//trace(stage.myXML.*);
//trace(my_mc.name);
my_mc.x = (100 + colWidth);
my_mc.y = myRowHeight;
colWidth = colWidth + 155;
//trace(myXML.*);
cellArray[arrayCount] = [my_mc.x, my_mc.y];
trace("CellArrayCount = " + cellArray[arrayCount]);
arrayCount = arrayCount + 1;
}
myRowHeight = myRowHeight + 105;
colWidth = 50;
}
Your trace is throwing an error because it is being executed before the XML is loaded.
ActionScript is asyncronous, which means that while the XML is being loaded, the program execution carries on going, and looks something like this:
Declare testXML:XML and myFPBxml:XML
Create loader and start loading
Add a listener for load completion
Trace testXML
Execute processFPBxml when the XML is loaded
If you move your trace into the myXMLTrace function then it will work correctly.
With the newly added code, the problem is with this line:
Object(this).my_mc.yellowHiLite.visible = false;
There is no need to use the this keyword at all here. This will work inside or outside a function:
my_mc.yellowHiLite.visible = false;
The reason your code fails inside a function is because inside and outside the function this will be the scope of the object in which this code resides. However, when you put the code into a function, the reference you create - my_mc - is scoped locally to the function, not to the parent object, and so this.my_mc is undefined, because this is not the function scope.
Are you taking the code out of the function it's currently in and calling the new function from where the code used to be? Or are you trying to define a function variable?
If you're only putting function blah() { ... } around code in the same place it is currently running, you'll get a syntax error for sure. In that case, try:
var blah:Function= function() { ... };
blah();
If you declare variables within a function they fall inside the scope of the function only.
It sounds like you are trying to access variables from elsewhere in your code.
So what you need to do is declare your variables outside of the function. e.g.
var one:VarType;
var two:VarType;
function blah():void {
trace(one);
}
I wondered if there is a simple way I have have a snippet which traces the name of a method when called. I found className which is half-way there, but not something for the method... a 1-line trace(...) is what I'm after so I avoid typing the method name and leaving myself open to mistakes.
This is for testing the order things happen, when I don't want to step through in the debugger.
If you have compiled your swf with debug information and use the debug version of the player you can take a look at getStackTrace property from the Error object:
Quick example:
public function getCallingInfos():Object{
var tmp:Array=new Error().getStackTrace().split("\n");
tmp=tmp[2].split(" ");
tmp=tmp[1].split("/");
return {namespaceAndClass:tmp[0], method:tmp[1]};
}
var infos:Object=getCallingInfos();
trace(infos.namespaceAndClass, infos.method);
public static function getCurrentClassName(c:Object):String
{
var cString:String = c.toString();
var cSplittedFirst:Array = cString.split('[object ');
var cFirstString:String = String(cSplittedFirst[1]);
var cSplittedLast:Array = cFirstString.split(']');
var cName:String = cSplittedLast.join('');
return cName;
}
Used to check if a certain class is constructed or not.
Usage (here I put the code in the main class):
trace('[DEBUG]: '+ClassData.getCurrentClassName(this)+' constructed.');
trace returns:
[DEBUG]: Main constructed.
If I have a method such as:
private function testMethod(param:string):void
{
// Get the object that called this function
}
Inside the testMethod, can I work out what object called us? e.g.
class A
{
doSomething()
{
var b:B = new B();
b.fooBar();
}
}
class B
{
fooBar()
{
// Can I tell that the calling object is type of class A?
}
}
Sorry the answer is no (see edit below). Functions received a special property called arguments and in AS2 it used to have the property caller that would do roughly what you want. Although the arguments object is still available in AS3 the caller property was removed from AS3 (and therefore Flex 3) so there is no direct way you can do what you want. It is also recommeded that you use the [...rest parameter](http://livedocs.adobe.com/flex/3/langref/statements.html#..._(rest)_parameter) language feature instead of arguments.
Here is a reference on the matter (search for callee to find the relevant details).
Edit: Further investigation has shown that it is possible to get a stack trace for the current executing function so if you are lucky you can do something with that. See this blog entry and this forum post for more details.
The basic idea from the blog post is you throw an Error and then catch it immediately and then parse the stack trace. Ugly, but it may work for you.
code from the blog post:
var stackTrace:String;
try { throw new Error(); }
catch (e:Error) { stackTrace = e.getStackTrace(); }
var lines:Array = stackTrace.split("\n");
var isDebug:Boolean = (lines[1] as String).indexOf('[') != -1;
var path:String;
var line:int = -1;
if(isDebug)
{
var regex:RegExp = /at\x20(.+?)\[(.+?)\]/i;
var matches:Array = regex.exec(lines[2]);
path = matches[1];
//file:line = matches[2]
//windows == 2 because of drive:\
line = matches[2].split(':')[2];
}
else
{
path = (lines[2] as String).substring(4);
}
trace(path + (line != -1 ? '[' + line.toString() + ']' : ''));
Is important to know that stackTrace is only available on the debugger version of Flash Player. Sorry! :(
I'd second the idea of explicitly passing a "callingObject" parameter. Unless you're doing really tricky stuff, it should be better for the caller to be able to supply the target object, anyway. (Sorry if this seems obvious, I can't tell what you're trying to accomplish.)
To add to the somewhat ambiguous first paragraph of James: the arguments property is still available inside a Function object, but the caller property has been removed.
Here's a link to the docs: http://livedocs.adobe.com/flex/3/langref/arguments.html
This might help someone, I'm not sure... but if one is using an Event this is possible using the e.currentTarget as follows:
private function button_hover(e:Event):void
{
e.currentTarget.label="Hovering";
}