Actionscript :: Functional Programming - Validating Parameters In A Provided Callback Function?
Feb 29, 2012
I don't think this is possible, but is there a way to validate the arguments a callback accepts. For example someone passes me callback "mycallback", I want to assert it accepts an argument String.
public function addHandler(handler : Function) : void{
//pseudo code
Assert.functionAcceptsArguments(handler, String);
}
I'm working with arrays in AS3 and some of the utility functions described in the livedocs such as filter() or some() would be very useful to me, if only I could pass parameters to them...
Actually, I cannot find a single example of the use of these functions with custom parameters passed to their callbacks. Everywhere, it is always used with constants ! E.g. on this page: [URL]
var arr:Array = new Array();var totalElements:uint = 100;for(var i:uint = 0; i<totalElements; i++) { arr[i] = Math.round(Math.random()*100);}function isLargerThan90(element:*, index:int, arr:Array):Boolean { return element > 90;}var highestNumbers:Array = arr.filter(isLargerThan90);trace(highestNumbers);
What I need is a kind of "isLargerThan" function with "90" as an argument's value, not as a constant. Something like
function isLargerThan(element:*, index:int, arr:Array, param:Object):Boolean { return element > (param as Number);}I find it very odd that I cannot find no mention of the way to do this on the whole WWW, because that makes these utility functions absolutely helpless in many many cases and programming with arrays a real pain...
myFunc(tracer); function tracer(message:String):void{ trace(message);[code]........
Now, this works fine. But how can the function myFunc know, if the given callback function accepts the correct number and type of arguments in its signature?I want to avoid that I call something like this somewhere in my code:
myFunc(tracer2); function tracer2():void{ trace("done");[code]..........
Is there a way to do something like this, in order to use compiler warnings/error messages and thus avoid exceptions at runtime?
// Won't work :-(
function myFunc(callback(message:String):Function):{ callback("Hello"); }
How do I keep the cycles active, and also call a function at the end of each cycle/tween? Right now I can remove the soundHammer call back and the tween will continue to cycle, and if I remove the cycle soundHammer is called properly, but obviously it doesn't cycle anymore.
Lets say I add a callback function to be run every frame the AS2 way. Code: this.onEnterFrame = myFunction; If I add another enter frame listener, will this replace the old one, or add to the old one, so both functions will run when frames are entered? And how do I remove these listeners?
My web application pass a javascript object to flex application using addCallback function. when the flex application is in modal dialog in safari browser, the object in the flex application is null and when I open the flex application just in a new window, the object is passed correctly. But, I need the showmodaldialog to show the flex application.
The flex code: ExternalInterface.addCallback( "handleEvent", handleEvent ); override public function handleEvent( event:Object ):Object { Alert.show(String(event)); .....
When you call a method of a class inside a callback function, you can not use this object.To call the method, in javascript, I declare that variable, assign this to that, and use that inside the callback to call the method of this.In actionscript, do I have to do the same way as I do in javascript?The following code is the example to use that to call a method inside callback.Are there more simple way in actionscript?
import caurina.transitions.Tweener; class Scanner extends MovieClip { public var Scanner00_mc:MovieClip; public var Scanner01_mc:MovieClip;
[Code].....
Makes sense as for the sequence, what doesn't make sense is why Tweener fail to loop back to the "fade" function ? They are suppose to be calling each other in an astable/blinking manner.
I suspect it's a scope problem but I don't know how to fix this, it seems AS2 Class doesn't know that there is a fade function within itself after the second Tweener call.
I rarely use NetStream or any video in my projects, but someone I email with was wondering this, and I have no earthly idea.
Is there any reason why the NetStream's "onMetaData" event cannot be listened to using addEventListener, but instead requires you to use a callback function?
Is it faster, avoiding the overhead of events? Is it to prevent more than one listener being attached?
I'm currently working with soundmanager2 in an IE/flash context (not html5). The issue is that audio playback of mp3 content does not occur for the following case where the 'onload' callback function is defined as null OR as a function that does almost nothing.
whenever I try to call the removeMovieClip function in a callback handler, it just doesn't work! Maybe I'm tired, or I've just missed something this is apparantly obvious. In my code exert below, is just a simple script that attaches a movie clip to stage (square_mc) and creates a duplicate instance. When the component button is clicked, I want the original movie clip to be deleted, but nothing happens!
Code: this.attachMovie("square", "square_mc", this.getNextHighestDepth()); square_mc.duplicateMovieClip("square_mc2", this.getNextHighestDepth(), {_x:50}) var listener:Object = new Object;[code].............
it seems to me that when you use laco tweens and callback a function, you can't pass data in that function, because the function won't wait until the tween is finished but is being carried out right away. For instance, I want to tween movieclip MC:
I'm having some trouble passing parameters with a function that is itself being passed as a parameter.In my application code I'm instancing that class five times:they are buttons in a menu.In that class, I've got an onRelease handler that does a number of things when a button is released, one of which is to invoke a function that is defined in the application level of the code.My problem is that I don't know how to send the function parameters.In my StandardButton class I have:
class StandardButton extends MovieClip { /* define properties */[code]..........
The function is successfully being "sent" to the StandardButton class, but without any parameters.How can I send parameters to the class instance with the way I've got this architected.
for (i=1; i<5; i++) { theClip="clip"+i; eval(theClip).onPress = function() { found(i); // passes the i variable to a hypothetical "found" function } } "theClip" evaluates correctly, i.e. clip1, clip2, clip3, clip4.
The i inside the callback function is useless though. Every clip's onPress function will pass 4 (the last loop #) to the "found" function. I must be totally missing some basic restriction on callbacks.
I have some functions that have mouseEvents for their param and I am wondering how those can be use without the param. Meaning those functions where set up to work with buttons, but how can call those when I don't have a button to call them? Here is an example of one of the functions:
function forward(e:MouseEvent):void { ns.togglePause();
Since I have to loop through all of them. I can convert them to an array inside the function, but it would save me 10 lines if I could just enter them as an array in the function parameter (as I have 10 variables 1-10...)
So say I have a function that has some number of optional parameters but I don't like to write the function more than once. Instead just use for loop or such to iterate the parameters through and give them to that function.
Here's a raw scetch:
ActionScript Code: // stylesheet for lines var params1 = { thicknes: 1,
i am loading an image with a loader, and in onComplete function i would like to call calculateRatio function and pass it Loader.content.width and Loader.content.height so it can compare it with the current stage width and height and resize image proporcionally to fit the screen. how would i go about passing that parameters?
I have a hard time getting this Code: var whichXML:String = "category1"; loadFirstTime(whichXML); function loadFirstTime(whichXML:String):void { XMLLoader = new URLLoader(); XMLLoader.load(new URLRequest(whichXML + ".xml")); }
I'm having a problem with a menu that is loaded from a xml file. I want to control the onRelease action for every button in the menu from one XML file, but I can't seem to get it to work... The buttons in the menu each have to call a different function with parameters which are declared in the flash file. The trace output shows the right function call, but it just won't fire the function.
This is an example of one of the nodes from my XML file with the function as node attribute:
Code: function enableButtons():void { for (var i:uint=0; i<40; i++)
[Code]...
I have 40 buttons on the stage. Their names are contained in the Array musicGrid. What I'm trying to do with this code is attach an EventListener to each button so that it will call the function mgMouseBehavior with a parameter to identify the button. For example, I want the button at musicGrid[0] to call the function mgMouseBehavior(0). I want the button at musicGrid[32] to call the function mgMouseBehavior(32), and so on.
However, if you try to add parameters to mgMouseBehavior in the addEventListener, for example: