On my air application, I try to load image like this:
var imAc:Image=new Image();
imAc.source=rootFile+value+"-V-"+label+".png";
Sometimes, image source doesn't exist.
In this case, broken icon appear but if this error appear I'd like to change image source
imAc.source= null
With mx:Image ioError property exist but I don't find the same with spark image.
Do you know how to do that?
Thanks
If you're using a spark image control, the ioError event can be used to trap the error and null out the value (or put up a placeholder image). If you need more granularity than that, or if you're in flex 3, you can use a Loader.
I'm not aware of any methods within the Spark Image component that allow you to check of its existence, but the File class does.
new File("your/file/path").exists
will return whether or not he file is present.
The result of this can then determine whether to set the source property to null.
Related
I'm trying to make a file that is easy for a non-flash user to use/reuse to easily display content. The key here is that this file is to be a template for a novice user to just copy/paste some very minimal code to create different "flash card" type swf files.
The file I am creating has multiple buttons on the main timeline which when clicked, attaches a movie clip which will display a dynamic text area with content specific for the button that was clicked. The content for the text area will be loaded from a separate text file.
For the sake of this example, I'm just going to refer to one button...
So, on the main timeline, in frame 1, I have a variable definition:
var myFilename1:String = "mySampleFile2.txt";
When the button on the main timeline, in frame 1 is pressed, a movie clip is loaded which contains a text area. The content for the text area is located in that file: mySampleFile2.txt.
If I hard-code the file name, it works like a dream:
myTextLoader.load(new URLRequest("mySampleFile2.txt"));
But I don't want to hard code the file name. I want to refer the variable in the main timeline. In AS 2, it would have been
myTextLoader.load(new URLRequest(_root.myFilename1));
In AS3 I thought it would be either:
myTextLoader.load(new URLRequest(root.myFilename1));
OR
myTextLoader.load(new URLRequest(MovieClip(this.parent.root).myFilename1));
When I run the code I get the following error and when I run a trace I get the file name is NULL.
TypeError: Error #2007: Parameter url must be non-null.
How to I access the file name stored in the variable on the main timeline?
*************************** UPDATE! *************************
So I just discovered that the issue is related to a button on the screen. The button is one from the buttons library. If I remove the button, everything works great. But as soon as that button is on the main timeline, it makes it to I cannot access the variables using MovieClip(root).variable_name;. Unfortunately I want that button to trigger the events within the MovieClip. Any thoughts?
Not a good idea
You are not able to achieve your goals with this bad practice approach.
to use/reuse
The code you want to provide is not very reusable. It heavily relies on one variable existing in a certain place. Therefore it cannot be use twice in a project.
But I don't want to hard code the file name.
And now you are hard coding the variable and its location. If you considered hard coding the file name to be a bad things, consider this a bad thing, too.
What the problem is
Basically speaking, the problem is that your component is reaching out to grab this variable from somewhere within your project. But it is not the concern of the component to find the content it should display. It is not well encapsulated.
Learning from existing things
You want to display text. Let's take a look at the TextField class to see how it displays text.
var tf:TextField = new TextField();
tf.text = "hello";
addChild(tf);
As you can see, the text that it should display is passed to the TextField object. There is not some arbitrary variable one has to set in order to modify the text, as you are planning to do:
var tf:TextField = new TextField();
var someArbitraryVariableThatModifiesATextField = "hello";
addChild(tf);
There is no obvious connection to the TextField object and if there's a second TextField, this doesn't work at all.
Applying that to the problem at hand
Just like the TextField, your "flash card" should receive the file as a parameter. Either pass it to the constructor as seen in the example below, or create a method that takes it as a parameter.
var card:Card = new Card("mySampleFile2.txt");
addChild(card);
Additional thoughts
Create additional methods to set the values individually. There's nothing worse than some code that does exactly what one wants, but only operates on files and one doesn't have a file. The goal is again, to make it easy to reuse the code
Use the [Inspectable] meta tag to allow the user of your code to modify the properties at author time. This can be used to the extend of modifying properties belonging to a physics engine, now this is what I would call easy to use for a novice user.
Instead of writing code and thus requiring to recompile the file again, take the information (either the path to the file or it content) from the flashars that are passed to the .swf file when it is embedded into an html page. This makes the single .swf file truely reusable and easiest to use, because there's no As3 coding required whatsoever.
I haven't tested this but I believe the "root"-stage would be:
this.parent
In the child swf.
check out this question: as3 access variable from parent swf
Good luck!
Accessing variables or movieclips at main timeline is as following:
AS2:
_root.variable_name;
AS3:
MovieClip(root).variable_name;
Where is good place to load image in custom itemrender for list. I try to do it in createChildren where i create my holder for image, but data is not set yet.. I think in data function is not ok, because is calinig every time when user scroll.
You need to set the data/url to the image in commitProperties.
You didn't tell us what the image is and how it relates to your itemRenderer. Here are a few options:
If your image will not change based on the data then create your image class in createChildren(). Set the property on it in the createChildren() method; if it is static. If it is something that may change you may consider setting it in commitProperties().
If your image will change based on the data; then you should change it either in the set data method or in a dataChange event handler. I prefer the latter, but that is just preference. An itemRenderer is re-used as the list is scrolled. So the data that your renderer represents changes with it; and so should your visual display.
If lots of the elements of your dataProvider may use the same image; you can write conditional logic to determine whether or not the image should be loaded again. This would prevent the image from reloading again unnecessarily.
I have a flash assignment that I need help getting started, any advice would be greatly appreciated. The assignment is to create an application for playing a card game, I have to create an MXML component that has two variables, one variable stores the image of the back of a playing card, the other variable has t store all 52 options of a front facing card (the second variable will store over 50 images).
I've written the variable for the back of the card image like this:
public var backOfCard:Image = new Image();
backofCard.source = 'asset/backImage';
However I get an undefined variable error (1120: Access of undefined propery variable img1), I feel like there's something small that I'm missing here, but I was wondering if anyone could spot it.
I'd also like to know if I should use the same method for each jpg image for the front of the cards, it seems like it would be a lot of repetitive code aside from the change in filename for the front of the card images.
Here's a snippet of the homework assignment, again I just need help getting this part correct, I really appreciate any help with this.
Your job is to supply the custom component named Card. Create the
component by using File → New → MXML Component. In the popup dialog
box
leave the Package blank
Name the component Card
Base Card on spark.components.Image
What goes into the Card component?
For each card, we'll want to be able to show the front face of the
card, or its back face. That means each card should have a place to
store information about what file to show as its front face, and what
file to show as its back face.
To do this, create two variables in the Card component to store the
file names. You might call these variables backImage and frontImage.
Your access modifier is what's bothering me.
If you're creating these definitions in your class file, then the first statement works:
public var backOfCard:Image = new Image();
But if you're in one of the methods, usually the constructor (sometimes called the ctor), or any other method of the application, you could use the 2nd statement:
backofCard.source = 'asset/backImage';
But the combination of both is what I think is confusing. Because the "access modifier" (i.e. public, private, internal, protected) is what you use to define variables and methods within a class. And since you're putting both side-by-side (a definition and an assignment statement), I think you're mixing when to declare them.
Since flex memory management is poor, objects once instantiated dont die very easily (even when they go out of scope), one would need to check on various properties of components. I am using one such thing to know if the screen (which is a display object) is in current view. For this I am turning on a boolean property (currently visible), and I am setting it true on show event of the display object.
What I need to know is, which event (something opposite of show, e.g left?) could be used when the screen is replaced by another display object?
Something like focusIn and focusOut from dotnet.
Or if there is some property which could directly tell me if the display object is currently in view (hasFocus doesnt seem to be giving me expected results).
Thanks.
You can Use PropertyChageEvent check the documentation and base of the newValue and kind property you can do some action :
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/mx/events/PropertyChangeEvent.html
hope this help
Name of the event is: removedFromStage.
I'm having an issue with Movieclips inside my Swf resizing to the wrong dimensions. I'm currently tracing the width of the offending clip every half second, and I can see the value change to an incorrect size at some interval in the logged output. I really want to see what code is changing the width. My plan was to extend Movieclip, override the set width property, and dump a stack trace when the value set is too low. This isn't so simple however. Flash is complaining about undefined reference to UI components that are on the Movieclip fla.
Is there a simple way to find out when/why this value changes? I cannot use a debugger.
edit:
The reason I cannot just extend MovieClip is because I am getting my Movieclip object from Event.currentTarget.content after using a Loader. I cannot point my Test (extends MovieClip) object at this return value because it is illegal to do so.
I'll explain the problem a little more and maybe someone will have another idea. I have an app with lots of different windows. They all open to a size of around 750x570. One of these windows contains a FusionChart. when I load this, according to my trace, the background Swf I am using changes to a dimension of about 2712x1930. This doesn't make sense to me because it looks the same size as before and at those dimensions it wouldn't even come close to fitting on my screen. If I then close the window and open another, the new window is tiny, but says it has the same dimensions as the original windows (750x570).
It is almost as if the window is scaling to the huge 2712x1930 without showing a change in size, and then showing the next window (750x570) as a size relative to what the huge window would look like. If that makes sense...
Maybe using a Proxy?
The Proxy class lets you override the default behavior of ActionScript operations (such as retrieving and modifying properties) on an object.
If you can see the trace you are doing and use a debug version of the flash player, try to override the property you want to check and trace the calling stack stack within the Error object:
public class Test extends Sprite() {
// property to watch
override public function set x(value:Number):void{
super.x=value;
// trace the calling stack work only in the flash debug player
trace((new Error()).getStackTrace());
}
}
what do you mean by "Flash is complaining about undefined reference to UI components that are on the Movieclip fla."?
your idea is absolutely the right solution in general... assuming the property doesn't change from within the runtime (which is rare, unless those properties are calculated) ...
when it comes to width and height, they are the two worst properties in the flash player API ... for reading, they are calculated by the space needed by a DisplayObject in parent coordinate space (if you rotate a DisplayObject, than these properties change). for writing, they actually forward to scaleX and scaleY ...