In my AIR application (with mate-Framework) i did follwing things:
click on a button
call a method in my model "onApplicationBusy"
apply some filter in arraycollections.
In my onApplicationBusy there is this code:
FlexGlobals.topLevelApplication.enabled = false;
FlexGlobals.topLevelApplication.
I trace every step and all methods are called in right order.
But my application never becomes disabled.
Why. Is there a method for this purpose.
I try InvalidateDisplayList or ValidateNow or callLater. But all tries won't work. Probably i try it on the wrong place?
I assume, my application is so busy while applying filters (4 values for 10.000 lines) that the disabled property can't processed.
If i call the method without applying the filters all works fine.
If i call just the disbaled property but never enable the app again, the app will shown as disabled after applying the filters. for me too late.
What i origin want is a clear behavior, when the app is busy and when not (ready for clicking on buttons and all this stuff).
If you can help me or know a method, how can i shown a busy application, please help me
Thanks
Frank
All right, the setTimeout Method solve my issue. I assume, I have to wait for the next screen refresh.
Why callLater won't work and when i have to implement those functions, because i have too less ressources while my filterFunction is running?
Frank
I'm using FlexGlobals.topLevelApplication.stage.mouseChildren = false | true;
Worth noting that I first tried setting the mouseEnabled flag but found various visual elements would not update at all while mouseEnabled = false.
Related
I'm writing a wizard UI based on the QWizard Qt object. There's one particular situation where I want the user to log in to a service using host, username, and password. The rest of the wizard then manipulates this service to do various setup tasks. The login may take a while, especially in error cases where the DNS name takes a long time to resolve -- or perhaps it may not even resolve at all.
So my idea is to make all three fields mandatory using the registerField mechanism, and when the user hits Next, we show a little throbber on the wizard page saying "Connecting to server, please wait..." while we try to connect in the background. If the connection succeeds, we advance to the next page. If not, we highlight the offending field and ask the user to try again.
However, I'm at a loss for how to accomplish this. The options I've thought of:
1) Override validatePage and have it start a thread in the background. Enter a wait inside validatePage() that pumps the Qt event loop until the thread finishes. You'd think this was the ugliest solution, but...
2) Hide the real Next button and add a custom Next button that, when clicked, dispatches my long running function in a thread and waits for a 'validation complete' signal to be raised by something. When that happens, we manually call QWizard::next() (and we completely bypass the real validation logic from validatePage and friends.) This is even uglier, but moves the ugliness to a different level that may make development easier.
Surely there's a better way?
It's not as visually appealing, but you could add a connecting page, and move to that page. If the connection succeeds, call next() on the wizard, and if the connection fails, call previous() and highlight the appropriate fields. It has the advantage of being relatively straightforward to code.
My final choice was #2 (override the Next button, simulate its behavior, but capture its click events manually and do the things I want to with it.) Writing the glue to define the Next button's behavior was minimal, and I was able to subclass QWizardPage with a number of hooks that let me run my task ON the same page, instead of having to switch to an interstitial page and worry about whether to go forwards or backwards. Thanks Caleb for your answer though.
I know this has already been answered (a long time ago!) but in case anyone else is having the same challenge. Another method for this is to create a QLineEdit, initiate it as empty and set it as a mandatory registered field. This will mean that "Next" is not enabled until it is filled with some text.
Run your connection task as normal and when it completes use setText to update the QLineEdit to "True" or "Logged in" or anything other than empty. This will then mean the built in isComplete function will be passed as this previously missing mandatory field is now complete. If you never add it to the layout then it won't be seen and the user won't be able to interact with it.
As an example ...
self.validated_field = QLineEdit("")
self.registerField('validated*', self.validated_field)
and then when your login process completes successfully
self.validated_field.setText("True")
This should do it and is very lightweight. Be sure though that you consider the scenario where a user then goes back to that page and whether you need to reset the field to blank. If that's the case then just add in the initialisePage() function to set it back to blank
self.validated_field.setText("")
Thinking about it you could also add the line edit to the display and disable it so that a user cannot update it and then give it a meaningful completion message to act as a status update...
self.validated_field = QLineEdit("")
self.validated_field.setDisabled(True)
self.validated_field.setStyleSheet("border:0;background-color:none")
self.main_layout.addWidget(self.validated_field)
self.registerField('validated*', self.validated_field)
and then when you update it..
self.validated_field.setText("Logged in")
I'll try to be as concise as possible. I have a number of objects in an array, and I'm applying event listeners to each one using closures:
//reduced to the logic in question:
buttons.forEach(function(button:EventDispatcher, i:int, list:Array):void {
button.addEventListener(MouseEvent.MOUSE_OVER, function(e:Event):void {
button.filters = [button_glow_filter];
});
});
//button-specific click handlers:
buttons[0].addEventListener(MouseEvent.MOUSE_CLICK, handle_some_action);
This works perfectly for a while, until I perform an unrelated action on the UI. It's a very complex system, so I'm not really sure what is happening. I can confirm that the unrelated action has no direct effect on the object that contains the buttons or the buttons themselves (at least, it's not changing anything via the public interfaces). The buttons still exist, and the click event listeners still work correctly because those are individually assigned real functions on the class's interface.
My question therefore is: does anyone know what can cause these closures to stop handling the MouseOver events without having any other perceptible effect on the related objects?
There are a number of ways to accomplish this MouseOver behavior, and for now I've switched to one that works, but I'd still like to know the answer to this question for future reference.
I figured out the likely culprit almost immediately after posting: garbage collection. It took just a couple of minutes to confirm. This is exactly what the useWeakReference parameter is for in the addEventListener interface; it defaults to true. By setting it to false, it prevents listeners assigned in this fashion from being garbage collected.
The correct code is:
buttons.forEach(function(button:EventDispatcher, i:int, list:Array):void {
button.addEventListener(MouseEvent.MOUSE_OVER, function(e:Event):void {
button.filters = [button_glow_filter];
}, false, 0, false);
});
I am using MVVM Light and am using Messages to communicate between ViewModels to let a ViewModel know when it is ok to execute something. My problem is that I register for a message and then it receives it multiple times. so to keep from my program executing something more than once I have to create boolean flags to see if it has already been recieved. Any idea why it does this and how I can stop it?
Make sure you unregister your message handlers once you do not need them anymore. The Messenger keeps a reference to the registered methods and this prevents them from being garbage collected.
Therefore, for ViewModels: make sure that you call Cleanup once you done (or implement IDisposable and call Cleanup from there).
For Views (Controls, Windows, or similar) call Messenger.Unregister in an event that occurs on the teardown of the view, e.g. the Unloaded event.
This is a known behaviour of the MVVM and has been discussed in several places.
Very old question but I solved the problem by doing this:
static bool isRegistered = false;
and then, in the constructor:
if( !isRegistered )
{
Messenger.Default.Register<MyMessage>(this, OnMessageReceived);
isRegisterd = true;
}
I have seen this issue before. It had to do with the Messenger.Default.Register being called more than once. The MVVMLight Messenger class will register the same item 'x' number of times. This is why when you call the Send you get it many times.
Anyone know how to prevent MVVMLight from registering multiple times?
really old but thought I would answer just in case somebody needs it. I was fairly new to silverlight at the time and the issue ended up being a memory leak as the viewModel, which had multiple instances, was still in memory.
As other contributors mentioned, the same message is being registered multiple times. I have noticed this behavior taking place while navigating to View X then navigating back to View Z where the message is registered in the constructor of the Z ViewModel. One solution is to set the NavigationCacheMode property to Required
<Page
........
........
NavigationCacheMode="Required">
I need to call FileReference.save() after a web service call has completed, but this method has a restriction: "In Flash Player, you can only call this method successfully in response to a user event (for example, in an event handler for a mouse click or keypress event). Otherwise, calling this method results in Flash Player throwing an Error exception." (from the documentation here)
This restriction is a bit vague. Does it mean that I can only call the FileReference.save() method from within an event handler function that is registered as a listener for certain types of user events? If so then exactly which user events are valid? (Perhaps there's an event that will never be dispatched by user interaction with my application and I could register an event handler function for that event type and make the save() call from within that function?)
My difficulty is that I can't safely call the FileReference.save() method until my web service returns with the data that will be used as the argument of the FileReference.save() method call, so the event that triggers the FileReference.save() call is actually a ResultEvent rather than a user event, and I'm leery of dispatching a new (faux) user event type in order to be able to trigger the FileReference.save() call unless it's definitely a user event that would never be dispatched as a result of actual user interaction with my application.
In a nutshell what I'm doing now is this: I have a function that is registered as a handler for a button click. In this function I make my web service call to fetch data from the server. I also have a result handler function which gets invoked when the web service call completes, and it's in here that I want to call the FileReference.save() method since it's at this point that I know that the data is ready to be saved to a file. But the aforementioned restriction is blocking me from doing this -- I get an error:
Error #2176: Certain actions, such as those that display a pop-up window,
may only be invoked upon user interaction, for example by a mouse click
or button press.
I've tried many things to get around this such as creating a second mouse click event handler function with the FileReference.save() call within and calling it after a timeout interval (to give the web service time to complete), but I keep running into the same error -- maybe that approach doesn't work since the second function isn't registered as an event listener for the event type used as its argument.
I'm new to Flex development so perhaps I'm just not thinking about this in the right way. If anyone can suggest another approach I'd really appreciate it. Thanks in advance for your comments or suggestions.
--James
Adobe does this as a sort of security measure to ensure users are the ones messing with files rather than potentially harmful code. My understanding is that they enforce this by only allowing handlers of (click?) events that originate from UI components to execute the FileReference methods, so generating your own events programmatically will not work, although I have not tried to verify this. Unfortunately the best resolution I've found is to re-work the UI a bit to conform to this constraint. In your particular situation, you could make this a two click process with a button that says something like "Prepare Download", which changes to "Download File" after the web service is complete. This is less than ideal from a user perspective, but I don't think there's much else that can be done unless you can somehow complete your web service call prior to displaying the button that triggers the FileReference.save() call.
After struggling for that for well, a couple hours I found a workaround: you can use both mouseDown AND mouseUp events instead of just click.
For instance:
s:Button
mouseDown="prepare_PDF()"
mouseUp="save_PDF()"
Works fine for me!
Happy coding!
--Thomas
As a workaround I used the ExternalInterface class. I created a javascript function with this code
function downloadFile (url) {
window.open(url);
}
An in AS3 I call
var url = 'www.example.com/downloadfile.php?file_id=xxx';
ExternalInterface.call('downloadAttachmentFile', url);
So with that I transfer the file handling to JS/HTML.
This is a comment on Thomas' answer (I don't have enough XP to comment yet): The mousedown and mouseup workaround works nicely. Just a note that if you make any changes in prepare_PDF() that need 'undoing' in save_PDF(), then its a good idea to call that code on the mouseout event as well, since there might be a case that the user mousedown's on the button, but then moves the mouse away from the button.
This was particularly relevant for my case, in which we increase the size of a watermark on an image when the user clicks the download button (that triggers the .save() call). I reduce the size of the watermark down to normal on the mousedown and mouseout events.
I had this same issue, I chose to use flash.net methods. Call flash.net.navigateToURL(url); from an actionscript or navigateToURL(url); from mxml.
What i do to solve this is to show an alert message with an anonymous function so i don't have to create a button.
Alert.show("Do you wish to download the file?", "Confirm", Alert.OK | Alert.CANCEL, this, function (eventObj:CloseEvent):void {
if (eventObj.detail == Alert.OK) {
fileReference.save(zipOut.byteArray, dateFormater_titulo.format(new Date ()) + ".zip");
}//if
}/*function*/, null, Alert.OK);
I am working with a pretty complicated .aspx page that is full of controls (Telerik, Ajax, etc.) that all expand, collapse, show, hide, etc. when the page is loaded. Since this rendering happens on the client-side and can take different lengths of time based on the users machine specs, is there a way to detect when all (or some) rendering has taken place (jQuery?) so I can then act on specific elements, knowing they are fully rendered?
JavaScript is single threaded. The time passed to setTimeout is a minimum, but not a maximum, so if you pass something like 10(ms), you essentially are saying "execute this code after all the currently running code is finished."
So, if all the controls use $(document).ready() to do their thing, all you need is:
$(document).ready(function() {
setTimeout(function() {
doStuff();
},10);
});
doStuff will be called after all the functions passed to $(document).ready have run. However, this isn't foolproof. If the controls have their own way of detecting whether the document has loaded, or do their own setTimeout(), you're in trouble. The problem is that JavaScript does not guarantee the execution order of setTimeouts. Sometimes your code may run last, other times it may run before the setTimeouts used for the animation.
One last idea: if all the animation is done using jQuery, then the effects run in a single queue. In doStuff you could add an animation of some sort with a callback and be reasonably certain that the callback would run last.
Whenever I had to wait for multiple things to be ready before proceeding, I would create an array with true/false values. Every mandatory part of the page got an event which, when it is called, updates the specific entry in the array to true. Also, it called a general function which returned true if all values in an array was true, otherwise false.
If that function finally returned true, I would proceed with the execution. It is especially useful if you have to wait for an AJAX call to end but don't want to use async = true. It also is useful if you want to start loading multiple things at once instead of one after another, since they all report ready-state to the same array.
It does however use global variables so you might need to do some optimizations. You might not want to do this approach either if you have a grudge against global variables.
You should place your code inside the jQuery $(document).ready() function. This will ensure that all elements are loaded before the code runs.
http://docs.jquery.com/Tutorials:Introducing_$(document).ready()
I think the doc you need is:
http://docs.jquery.com/Events/load
"I can then act on specific elements, knowing they are fully rendered?"
You can use the load method (linked above) to attach to any element. So if you had a div with an id of "lastElement", you could write
$('div#lastElement).load(runThisFunction);