I'm trying to convert an image in my assets folder
"./assets/image1.png"
to type Object. It needs to be Object because that's what the function I'm using it in is expecting.
Any ideas what would be the simplest way to do this?
Do you mean something like :
[Embed(source="assets/logo.jpg")]
private var logo:Class;
private function init(e:Event):void
{
this.displayImage(logo as Object);
}
private function displayImage(img:Object):void
{
//Assuming you have an image control on stage with an instance
//name of "myImage"
myImage.source = img;
}
If the function you are passing the image to is expecting an Object object, you can in pass anything, it won't reject it. That doesn't mean the function will work correctly, though. Any value will be an Object (except for undefined, which will be accepted but coerced to null and maybe some other strange cases).
So, assuming you didn't write the function yourself, do you have any doc that describes what it expects? Or maybe you have the source code for it?. Otherwise, if the only thing you know about what this function expects is that the parameter must be of type Object... you're in trouble, I think.
Why don't you create a new Object containing the information about the image... including the path.
var obj:Object = new Object();
obj.path = "/assets/image.jpg";
obj.height = 32;
obj.width = 32;
trace(obj.path);
// or, if Flex
Alert.show(obj.path);
And then just pass the new Object into the function and access it like I have above.
Related
When using ObjectUtil.copy() on my object, I get the following error
Argument count mismatch on foo.bar::MyObject(). Expected 1, got 0.
MyObject's constructor takes in one parameter. Is there a way for me to clone, or copy it?
Use the ObjectUtil.clone method. That should do deep copies.
However, I'm not sure if that will solve the issue.
In Flex 4.5 Neither copy, nor clone, create a new version of the object using the new keyword; therefore the constructor is never called. Both do byte array copies. I'd be interested to see your code.
I use:
public static function clone(source:Object):* {
var myBA:ByteArray = new ByteArray();
myBA.writeObject(source);
myBA.position = 0;
return(myBA.readObject());
}
Never let me down.
I've just found a strange error when deserializing from a ByteArray, where Vectors cannot contain types that extend Array: there is a TypeError when they are deserialized.
TypeError: Error #1034: Type Coercion failed: cannot convert []#4b8c42e1 to com.myapp.ArraySubclass.
at flash.utils::ByteArray/readObject()
at com.myapp::MyApplication()[/Users/aaaidan/MyApp/com/myapp/MyApplication.as:99]
Here's how:
public class Application extends Sprite {
public function Application() {
// register the custom class
registerClassAlias("MyArraySubclass", MyArraySubclass);
// write a vector containing an array subclass to a byte array
var vec:Vector.<MyArraySubclass> = new Vector.<MyArraySubclass>();
var arraySubclass:MyArraySubclass = new MyArraySubclass();
arraySubclass.customProperty = "foo";
vec.push(arraySubclass);
var ba:ByteArray = new ByteArray();
ba.writeObject(arraySubclass);
ba.position = 0;
// read it back
var arraySubclass2:MyArraySubclass = ba.readObject() as MyArraySubclass; // throws TypeError
}
}
public class MyArraySubclass extends Array {
public var customProperty:String = "default";
}
It's a pretty specific case, but it seems very odd to me. Anyone have any ideas what's causing it, or how it could be fixed?
well, it seems array serialization is hardcoded. you should definitely post a bug report.
actually the code you posted doesn't throw an error since ba.readObject() as MyArraySubclass is simply null. MyArraySubclass(ba.readObject()) however would.
what you could try to fix it, would be to implement IExternalizable, altough I'm not sure it'll work any better.
I guess the problem is that Array is a very very special class in ActionScript (in the sense that in some way it is nothing more than any other dynamic class, but in other ways it's not at all) which leads to a lot of Array-specific code in the VM. Also, a question is, why do you need to subclass Array?
I have a "format" method that works in a similar manner to the C# String.Format method, with the following signature:
In a class named StringTools:
/**
* Formats a string, based on C# String.Format method.
* #param raw A string with numbered tokens, such as "{0}, {1}"
* #param rest Values that replace the numbered tokens in raw.
*/
public static function format(raw:String, ...rest:*):String;
StringTools.format("{0}, {1}", "Hello", "World") returns the string "Hello, World" as expected. Now, I'm trying to get my logging class to use this method, but I'm having trouble passing the optional variables through. The signature of the method in the logging class is:
public static function infof(raw:String, ...rest:*):String;
If I pass "rest" directly into StringTools.format(raw, rest), it's passed in as an array, and not as a series of parameters, so if I call it liks this: infof("{0}, {1}", "Hello", "World"), I get the string "Hello,World, {1}", since it replaces the first token with the entire array of values.
I also tried constructing an arguments array, and calling the method like this:
var collectArgs:Array = [raw];
for (var i:Number = 0; i < rest.length; i++)
{
collectArgs.push(rest[i]);
}
var callFunction:Function = StringTools.format.call;
trace(callFunction.apply(null, collectArgs));
However, this traces "World,6". So, it looks like the parameters are shifted. So, I tried initializing collectArgs as [null, raw], and I get "Hello World,6. The number is {1}" again.
Am I doing something wrong? What is the correct way to pass optional parameters from one method that expects optional parameters to another method that expects optional parameters?
Thanks!
I think you are on the right lines using apply. This seems to do illustrate the behaviour you want:
static function f1(raw:String, ...rest:*):void
{
trace("f1: "+raw+" "+rest);
rest.unshift(raw);
f2.apply(null, rest);
}
static function f2(raw:String, ...rest:*):void
{
trace("f2: "+raw+" "+rest);
}
function passSomeArguments():void
{
f1("A",1,2,3);
}
EDIT: You need to pass 'null' as the 1st parameter to apply because the first parameter is what is considered to be 'this' when the function is called. Since the functions are static (and in any case have no dependency on 'this') you can pass null, but you must pass something.
You could also do something like this (of course this is not best implementation for the string formatting):
public static function format(raw:String, ...rest:*):String {
if (rest[0] is Array && rest.length == 1) {
rest = rest[0];
}
var r:RegExp = /(\{\d+\})/g;
var matches:Array = raw.match(r);
for (var i:Number = 0; i < rest.length; i++) {
raw = raw.replace(matches[i], rest[i]);
}
return raw;
}
Then your infof function would just look like this:
public static function infof(raw:String, ...rest:*):void {
var formatted = StringTools.format(raw, rest);
}
As mentioned in my comment, if you remove the call method from the end of you callFunction setter, then you do not need to supply null as the first argument. See http://livedocs.adobe.com/ to understand what the call method actually does, and what the first parameter is for.
As #stephen mentioned, it is a lot simpler to unshift your raw var onto the rest array, rather than building up a new one.
Actually, just found that it's my problem. It should work fine using the argument collection method described, as long as the first element in the arguments array is null. I'm not sure why null is necessary, but it works fine this way.
I have a list of error codes I need to reference, kinda like this:
Code / Error Message
A01 = whatever error
U01 = another error
U02 = yet another error type
I get the Code returned to me via a web service call and I need to display or get the readable error. So I need a function when passed a Code that returns the readable description. I was just going to do a select case but thought their might be a better way. What is the best way / most effieient way to do this?
Use a Dictionary, (in C#, but the concept and classes are the same):
// Initialize this once, and store it in the ASP.NET Cache.
Dictionary<String,String> errorCodes = new Dictionary<String,String>();
errorCodes.Add("A01", "Whatever Error");
errorCodes.Add("U01", "Another Error");
// And to get your error code:
string ErrCode = errorCodes[ErrorCodeFromWS];
You would use a dictionary. A dictionary uses a hashmap internally for performance, so it is good in that regard. Also, because you want this to go as quickly as possible by the sounds of it, I would statically initialize it in its own class instead of, for example, in an XML file or slimier. You would probably want something like:
public static class ErrorCodes
{
private static Dictonary<string, string> s_codes = new Dicontary<string, string>();
static ErrorCodes()
{
s_codes["code"] = "Description";
s_codes["code2"] = "Description2";
}
public static string GetDesc(string code)
{
return s_codes[code];
}
}
That way, if you wanted to move the back end to a file instead of being static, then you could.
I am a Java programmer and need to work on a Flex/ActionScript project right now. I got an example of using ITreeDataDesriptor from Flex 3 Cookbook, but there is one line of actionscript code that's hard for me to understand. I appreciate if someone could explain this a little further.
public function getData(node:Object, model:Object=null):Object
{
if (node is Office) {
return {children:{label:node.name, label:node.address}};
}
}
The part that I didn't understand was "{children:{label:node.name, label:node.address}}". Office is simply a value object that contains two String properties: name and address.
The following return expression (modified from the question) ...
return {children:{label:node.name, body:node.address}}
... is functionally equivalent to this code ...
var obj:Object = new Object();
obj.children = new Object();
obj.children.label = node.name;
obj.children.body = node.address;
return obj;
The anonymous object returned in the question code complicates matters because it defines a property twice. In that case, the first declaration is used, and the subsequent one(s) are ignored. No compile-time or runtime error is thrown.
I think in Java you would call that a map or an associative array. In Javascript and Actionscript you can say this to create an object with certain properties:
var myobject = {
'prop1': 100,
'prop2': {
'a': 1
}
}
trace( myobject.prop1 ); // 100
trace( myobject.prop2.a ); // 1
In your example it's just returned as a nameless object.
return {children:{label:node.name, label:node.address}};
Means you are returning a new Object. The {} are the Object's constructor, and in this case its an Anonymous object.
Thank you both for the quick response. So if I understand your explanations correctly, the return statement is returning an anonymous object, and this object has only one property named "children", which is again an associative array - ok, here is the part I don't quite understand still, it seems that both properties in this array are named "label", is this allowed?