how to manage windows in external applications - apache-flex

I have 2 AIR applications (A and B) that are able to communicate via a LocalConnection object. I've verified that messages are definitely being sent/received appropriately.
I want to be able to have A tell B to come to the front. Both applications are full screen:
stage.fullScreenSourceRect = new Rectangle(0, 0, 1080, 1920);
stage.displayState = StageDisplayState.FULL_SCREEN_INTERACTIVE;
I've tried several permutations, but as of yet nothing seems to work.
private function initSlave(channel: String): void {
conn = new LocalConnection();
conn.client = {
'activateSlave': activateSlave
};
conn.allowDomain("*");
conn.connect("_" + channel);
}
private function activateSlave(): void {
stage.nativeWindow.orderToFront();
// or
stage.nativeWindow.activate();
// or
stage.nativeWindow.alwaysInFront = true;
stage.nativeWindow.alwaysInFront = false;
}
If I leave both applications in windowed mode (stage.displayState = StageDisplayState.NORMAL), then toggling alwaysInFront actually works. Calling activate() or orderToFront() still do nothing. If I try to toggle alwaysInFront and then set the application to fullscreen, the application ends up fullscreen behind my windowed app. Maybe there is an event I should wait for before setting the app to fullscreen?
I found a thread mentioning that orderToFront() only works relative to windows within the same application, which explains why it doesn't seem to do anything.
Does anyone have any insights into pulling this off? Maybe there is a way for me to embed B into application A so they are actually the same application? I am not sure how to do this with an AIR application as simply as just loading the SWF due to requiring external resources.

As no one else has offered a solution, I'll just mention quickly the hack that I'm using. Basically I have 2 LocalConnection channels, one from A to B, and one from B to A.
The visible program (e.g. A) will then fade to white, set visible to false, and send a message to B giving up control. B has initialized itself with stage.nativeWindow.visible = false, and when it receives the message from A it goes visible as a full white screen and fades in the GUI. There is a slight offset before A sets visible to false to give B time to display, otherwise there is a pop in the brief moment when both windows are minimized.
Anyway, there you go, it's ugly but it actually works fairly well.

Related

How to do a kill(pid, SIGINT) in windows? [duplicate]

I have (in the past) written cross-platform (Windows/Unix) applications which, when started from the command line, handled a user-typed Ctrl-C combination in the same way (i.e. to terminate the application cleanly).
Is it possible on Windows to send a Ctrl-C/SIGINT/equivalent to a process from another (unrelated) process to request that it terminate cleanly (giving it an opportunity to tidy up resources etc.)?
I have done some research around this topic, which turned out to be more popular than I anticipated. KindDragon's reply was one of the pivotal points.
I wrote a longer blog post on the topic and created a working demo program, which demonstrates using this type of system to close a command line application in a couple of nice fashions. That post also lists external links that I used in my research.
In short, those demo programs do the following:
Start a program with a visible window using .Net, hide with pinvoke, run for 6 seconds, show with pinvoke, stop with .Net.
Start a program without a window using .Net, run for 6 seconds, stop by attaching console and issuing ConsoleCtrlEvent
Edit: The amended solution from #KindDragon for those who are interested in the code here and now. If you plan to start other programs after stopping the first one, you should re-enable CTRL+C handling, otherwise the next process will inherit the parent's disabled state and will not respond to CTRL+C.
[DllImport("kernel32.dll", SetLastError = true)]
static extern bool AttachConsole(uint dwProcessId);
[DllImport("kernel32.dll", SetLastError = true, ExactSpelling = true)]
static extern bool FreeConsole();
[DllImport("kernel32.dll")]
static extern bool SetConsoleCtrlHandler(ConsoleCtrlDelegate HandlerRoutine, bool Add);
delegate bool ConsoleCtrlDelegate(CtrlTypes CtrlType);
// Enumerated type for the control messages sent to the handler routine
enum CtrlTypes : uint
{
CTRL_C_EVENT = 0,
CTRL_BREAK_EVENT,
CTRL_CLOSE_EVENT,
CTRL_LOGOFF_EVENT = 5,
CTRL_SHUTDOWN_EVENT
}
[DllImport("kernel32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool GenerateConsoleCtrlEvent(CtrlTypes dwCtrlEvent, uint dwProcessGroupId);
public void StopProgram(Process proc)
{
//This does not require the console window to be visible.
if (AttachConsole((uint)proc.Id))
{
// Disable Ctrl-C handling for our program
SetConsoleCtrlHandler(null, true);
GenerateConsoleCtrlEvent(CtrlTypes.CTRL_C_EVENT, 0);
//Moved this command up on suggestion from Timothy Jannace (see comments below)
FreeConsole();
// Must wait here. If we don't and re-enable Ctrl-C
// handling below too fast, we might terminate ourselves.
proc.WaitForExit(2000);
//Re-enable Ctrl-C handling or any subsequently started
//programs will inherit the disabled state.
SetConsoleCtrlHandler(null, false);
}
}
Also, plan for a contingency solution if AttachConsole() or the sent signal should fail, for instance sleeping then this:
if (!proc.HasExited)
{
try
{
proc.Kill();
}
catch (InvalidOperationException e){}
}
The closest that I've come to a solution is the SendSignal 3rd party app. The author lists source code and an executable. I've verified that it works under 64-bit windows (running as a 32-bit program, killing another 32-bit program), but I've not figured out how to embed the code into a windows program (either 32-bit or 64-bit).
How it works:
After much digging around in the debugger I discovered that the entry point that actually does the behavior associated with a signal like ctrl-break is kernel32!CtrlRoutine. The function had the same prototype as ThreadProc, so it can be used with CreateRemoteThread directly, without having to inject code. However, that's not an exported symbol! It's at different addresses (and even has different names) on different versions of Windows. What to do?
Here is the solution I finally came up with. I install a console ctrl handler for my app, then generate a ctrl-break signal for my app. When my handler gets called, I look back at the top of the stack to find out the parameters passed to kernel32!BaseThreadStart. I grab the first param, which is the desired start address of the thread, which is the address of kernel32!CtrlRoutine. Then I return from my handler, indicating that I have handled the signal and my app should not be terminated. Back in the main thread, I wait until the address of kernel32!CtrlRoutine has been retrieved. Once I've got it, I create a remote thread in the target process with the discovered start address. This causes the ctrl handlers in the target process to be evaluated as if ctrl-break had been pressed!
The nice thing is that only the target process is affected, and any process (even a windowed process) can be targeted. One downside is that my little app can't be used in a batch file, since it will kill it when it sends the ctrl-break event in order to discover the address of kernel32!CtrlRoutine.
(Precede it with start if running it in a batch file.)
I guess I'm a bit late on this question but I'll write something anyway for anyone having the same problem.
This is the same answer as I gave to this question.
My problem was that I'd like my application to be a GUI application but the processes executed should be run in the background without any interactive console window attached. I think this solution should also work when the parent process is a console process. You may have to remove the "CREATE_NO_WINDOW" flag though.
I managed to solve this using GenerateConsoleCtrlEvent() with a wrapper app. The tricky part is just that the documentation is not really clear on exactly how it can be used and the pitfalls with it.
My solution is based on what is described here. But that didn't really explain all the details either and with an error, so here is the details on how to get it working.
Create a new helper application "Helper.exe". This application will sit between your application (parent) and the child process you want to be able to close. It will also create the actual child process. You must have this "middle man" process or GenerateConsoleCtrlEvent() will fail.
Use some kind of IPC mechanism to communicate from the parent to the helper process that the helper should close the child process. When the helper get this event it calls "GenerateConsoleCtrlEvent(CTRL_BREAK, 0)" which closes down itself and the child process. I used an event object for this myself which the parent completes when it wants to cancel the child process.
To create your Helper.exe create it with CREATE_NO_WINDOW and CREATE_NEW_PROCESS_GROUP. And when creating the child process create it with no flags (0) meaning it will derive the console from its parent. Failing to do this will cause it to ignore the event.
It is very important that each step is done like this. I've been trying all different kinds of combinations but this combination is the only one that works. You can't send a CTRL_C event. It will return success but will be ignored by the process. CTRL_BREAK is the only one that works. Doesn't really matter since they will both call ExitProcess() in the end.
You also can't call GenerateConsoleCtrlEvent() with a process groupd id of the child process id directly allowing the helper process to continue living. This will fail as well.
I spent a whole day trying to get this working. This solution works for me but if anyone has anything else to add please do. I went all over the net finding lots of people with similar problems but no definite solution to the problem. How GenerateConsoleCtrlEvent() works is also a bit weird so if anyone knows more details on it please share.
Somehow GenerateConsoleCtrlEvent() return error if you call it for another process, but you can attach to another console application and send event to all child processes.
void SendControlC(int pid)
{
AttachConsole(pid); // attach to process console
SetConsoleCtrlHandler(NULL, TRUE); // disable Control+C handling for our app
GenerateConsoleCtrlEvent(CTRL_C_EVENT, 0); // generate Control+C event
}
Edit:
For a GUI App, the "normal" way to handle this in Windows development would be to send a WM_CLOSE message to the process's main window.
For a console app, you need to use SetConsoleCtrlHandler to add a CTRL_C_EVENT.
If the application doesn't honor that, you could call TerminateProcess.
Here is the code I use in my C++ app.
Positive points :
Works from console app
Works from Windows service
No delay required
Does not close the current app
Negative points :
The main console is lost and a new one is created (see FreeConsole)
The console switching give strange results...
// Inspired from http://stackoverflow.com/a/15281070/1529139
// and http://stackoverflow.com/q/40059902/1529139
bool signalCtrl(DWORD dwProcessId, DWORD dwCtrlEvent)
{
bool success = false;
DWORD thisConsoleId = GetCurrentProcessId();
// Leave current console if it exists
// (otherwise AttachConsole will return ERROR_ACCESS_DENIED)
bool consoleDetached = (FreeConsole() != FALSE);
if (AttachConsole(dwProcessId) != FALSE)
{
// Add a fake Ctrl-C handler for avoid instant kill is this console
// WARNING: do not revert it or current program will be also killed
SetConsoleCtrlHandler(nullptr, true);
success = (GenerateConsoleCtrlEvent(dwCtrlEvent, 0) != FALSE);
FreeConsole();
}
if (consoleDetached)
{
// Create a new console if previous was deleted by OS
if (AttachConsole(thisConsoleId) == FALSE)
{
int errorCode = GetLastError();
if (errorCode == 31) // 31=ERROR_GEN_FAILURE
{
AllocConsole();
}
}
}
return success;
}
Usage example :
DWORD dwProcessId = ...;
if (signalCtrl(dwProcessId, CTRL_C_EVENT))
{
cout << "Signal sent" << endl;
}
A solution that I have found from here is pretty simple if you have python 3.x available in your command line. First, save a file (ctrl_c.py) with the contents:
import ctypes
import sys
kernel = ctypes.windll.kernel32
pid = int(sys.argv[1])
kernel.FreeConsole()
kernel.AttachConsole(pid)
kernel.SetConsoleCtrlHandler(None, 1)
kernel.GenerateConsoleCtrlEvent(0, 0)
sys.exit(0)
Then call:
python ctrl_c.py 12345
If that doesn't work, I recommend trying out the windows-kill project:
Choco: https://github.com/ElyDotDev/windows-kill
Node: https://github.com/ElyDotDev/node-windows-kill
void SendSIGINT( HANDLE hProcess )
{
DWORD pid = GetProcessId(hProcess);
FreeConsole();
if (AttachConsole(pid))
{
// Disable Ctrl-C handling for our program
SetConsoleCtrlHandler(NULL, true);
GenerateConsoleCtrlEvent(CTRL_C_EVENT, 0); // SIGINT
//Re-enable Ctrl-C handling or any subsequently started
//programs will inherit the disabled state.
SetConsoleCtrlHandler(NULL, false);
WaitForSingleObject(hProcess, 10000);
}
}
Thanks to jimhark's answer and other answers here, I found a way to do it in PowerShell:
$ProcessID = 1234
$MemberDefinition = '
[DllImport("kernel32.dll")]public static extern bool FreeConsole();
[DllImport("kernel32.dll")]public static extern bool AttachConsole(uint p);
[DllImport("kernel32.dll")]public static extern bool GenerateConsoleCtrlEvent(uint e, uint p);
public static void SendCtrlC(uint p) {
FreeConsole();
if (AttachConsole(p)) {
GenerateConsoleCtrlEvent(0, p);
FreeConsole();
}
AttachConsole(uint.MaxValue);
}'
Add-Type -Name 'dummyName' -Namespace 'dummyNamespace' -MemberDefinition $MemberDefinition
[dummyNamespace.dummyName]::SendCtrlC($ProcessID)
What made things work was sending the GenerateConsoleCtrlEvent to the desired process group instead of sending it to all processes that share the console of the calling process and then AttachConsole back to the current process' parent's console.
Yes. The https://github.com/ElyDotDev/windows-kill project does exactly what you want:
windows-kill -SIGINT 1234
It should be made crystal clear because at the moment it isn't.
There is a modified and compiled version of SendSignal to send Ctrl-C (by default it only sends Ctrl+Break). Here are some binaries:
(2014-3-7) : I built both 32-bit and 64-bit version with Ctrl-C, it's called SendSignalCtrlC.exe and you can download it at: https://dl.dropboxusercontent.com/u/49065779/sendsignalctrlc/x86/SendSignalCtrlC.exe https://dl.dropboxusercontent.com/u/49065779/sendsignalctrlc/x86_64/SendSignalCtrlC.exe -- Juraj Michalak
I have also mirrored those files just in case:
32-bit version: https://www.dropbox.com/s/r96jxglhkm4sjz2/SendSignalCtrlC.exe?dl=0
64-bit version: https://www.dropbox.com/s/hhe0io7mcgcle1c/SendSignalCtrlC64.exe?dl=0
Disclaimer: I didn't build those files. No modification was made to the compiled
original files. The only platform tested is the 64-bit Windows 7. It is recommended to adapt the source available at http://www.latenighthacking.com/projects/2003/sendSignal/ and compile it yourself.
In Java, using JNA with the Kernel32.dll library, similar to a C++ solution. Runs the CtrlCSender main method as a Process which just gets the console of the process to send the Ctrl+C event to and generates the event. As it runs separately without a console the Ctrl+C event does not need to be disabled and enabled again.
CtrlCSender.java - Based on Nemo1024's and KindDragon's answers.
Given a known process ID, this consoless application will attach the console of targeted process and generate a CTRL+C Event on it.
import com.sun.jna.platform.win32.Kernel32;
public class CtrlCSender {
public static void main(String args[]) {
int processId = Integer.parseInt(args[0]);
Kernel32.INSTANCE.AttachConsole(processId);
Kernel32.INSTANCE.GenerateConsoleCtrlEvent(Kernel32.CTRL_C_EVENT, 0);
}
}
Main Application - Runs CtrlCSender as a separate consoless process
ProcessBuilder pb = new ProcessBuilder();
pb.command("javaw", "-cp", System.getProperty("java.class.path", "."), CtrlCSender.class.getName(), processId);
pb.redirectErrorStream();
pb.redirectOutput(ProcessBuilder.Redirect.INHERIT);
pb.redirectError(ProcessBuilder.Redirect.INHERIT);
Process ctrlCProcess = pb.start();
ctrlCProcess.waitFor();
I found all this too complicated and used SendKeys to send a CTRL-C keystroke to the command line window (i.e. cmd.exe window) as a workaround.
A friend of mine suggested a complete different way of solving the problem and it worked for me. Use a vbscript like below. It starts and application, let it run for 7 seconds and close it using ctrl+c.
'VBScript Example
Set WshShell = WScript.CreateObject("WScript.Shell")
WshShell.Run "notepad.exe"
WshShell.AppActivate "notepad"
WScript.Sleep 7000
WshShell.SendKeys "^C"
// Send [CTRL-C] to interrupt a batch file running in a Command Prompt window, even if the Command Prompt window is not visible,
// without bringing the Command Prompt window into focus.
// [CTRL-C] will have an effect on the batch file, but not on the Command Prompt window itself -- in other words,
// [CTRL-C] will not have the same visible effect on a Command Prompt window that isn't running a batch file at the moment
// as bringing a Command Prompt window that isn't running a batch file into focus and pressing [CTRL-C] on the keyboard.
ulong ulProcessId = 0UL;
// hwC = Find Command Prompt window HWND
GetWindowThreadProcessId (hwC, (LPDWORD) &ulProcessId);
AttachConsole ((DWORD) ulProcessId);
SetConsoleCtrlHandler (NULL, TRUE);
GenerateConsoleCtrlEvent (CTRL_C_EVENT, 0UL);
SetConsoleCtrlHandler (NULL, FALSE);
FreeConsole ();
SIGINT can be send to program using windows-kill, by syntax windows-kill -SIGINT PID, where PID can be obtained by Microsoft's pslist.
Regarding catching SIGINTs, if your program is in Python then you can implement SIGINT processing/catching like in this solution.
Based on process id, we can send the signal to process to terminate forcefully or gracefully or any other signal.
List all process :
C:\>tasklist
To kill the process:
C:\>Taskkill /IM firefox.exe /F
or
C:\>Taskkill /PID 26356 /F
Details:
http://tweaks.com/windows/39559/kill-processes-from-command-prompt/

How to use the IBandClient addtileasync method within an mvvm project such as template10 Minimal

The addtileasync method on the BandClient opens a modal dialog asking permission to install the tile on the Microsoft Band. But in an mvvm application like Template10 the dialog is not presented and the tile is not added. How would this method be implemented given an mvvm implementation?
I ran into the same problem...I'm using Caliburn Micro without Template10, but I believe the overall architecture is similar. As best as I can determine, that popup is implemented by assuming that Window.Current is a Frame which it tries to grab, navigate to the auth dialog and then navigate back after the user approves. I tried several approaches and the one that currently works for me (although a complete kludge that I'm not thrilled with) is to inject a Frame as you mention above. However, before doing so, I copy my ShellView into a public property on App so that I can go back to it after adding the tile. My code looks basically like this:
When I need to add the Tile (on a Setting View):
((App)Application.Current).ShellHolder = Window.Current.Content;
Frame rootFrame = Window.Current.Content as Frame;
if (rootFrame == null)
{
rootFrame = new Frame();
Window.Current.Content = rootFrame;
}
rootFrame.Navigate(typeof(BandAddTileView));
Window.Current.Activate();
Then, in the BandTileView when it's logic is wrapped up, I call something like this:
private void ResetShell(BandTileResult result) {
var app = (App)Application.Current;
if (app == null) return;
app.TileResult = result;
Window.Current.Content = (UIElement)app.ShellHolder;
Window.Current.Activate();
}
I then have some logic in when ShellView comes back in play that navigates back to the Settings View and deals with the BandTileResult.
Like I said, it's a kludge and not entirely elegant but it seems to working OK and with a little styling on the BandAddTileView it presents a pretty good user experience for the app user.
Any feedback from the band dev team would definitely be welcome on a better MVVM approach!

MediaPlayer MediaOpenned event is not firing on .net class

I'm trying to build a class where my thumbnail class is capturing a frame as a thumbnail of the videos users uploaded, things have gone good so far. I've written down the application on wpf app first and then decided to move to a class on my website as thumbnail.cs. Code is as shown below.
My problem is, the MediaOpenned event doesn't fire up so the execution cannot continue as its supposed to, i tried calling it myself and put a thread.sleep to handle the delay with the buffering of video and the code worked as i wanted. But i don't want to rely on sleep since it can be unstable due to server and heavy.. I need it to work with the event or something similar like that.
Any ideas or suggestions why event is not firing on .net? while working perfect on wpf? and what to do.
And millions of thanks of course!
thumbnail.cs class;
MediaPlayer myPlayer = new MediaPlayer();
public thumbnail()
{
myPlayer.Open(new Uri(#"C:\movie.wmv"));
myPlayer.Play();
myPlayer.IsMuted = true;
//this doesn't fire up
myPlayer.MediaOpened += new EventHandler(myPlayer_MediaOpened);
/*
when i do like this it works as i want but unstable and heavy because sleep
myPlayer_MediaOpened(null, null);
System.Threading.Thread.Sleep(5000);
*/
}
void myPlayer_MediaOpened(object sender, EventArgs e)
{
myPlayer.Position = TimeSpan.FromSeconds(myPlayer.NaturalDuration.TimeSpan.Seconds / 2);
RenderTargetBitmap RenderTarBitmap = new RenderTargetBitmap(400, 300, 1 / 96, 1 / 96, PixelFormats.Pbgra32);
DrawingVisual DVisual = new DrawingVisual();
DrawingContext DContext = DVisual.RenderOpen();
DContext.DrawVideo(myPlayer, new Rect(0, 0, 400, 300));
DContext.Close();
RenderTarBitmap.Render(DVisual);
myPlayer.Stop();
BitmapFrame BMPFrame = BitmapFrame.Create(RenderTarBitmap);
BitmapEncoder BMPEncoder = new JpegBitmapEncoder();
System.IO.FileStream FStream = new System.IO.FileStream(#"C:\movie.jpg", System.IO.FileMode.Create);
BMPEncoder.Frames.Add(BMPFrame);
BMPEncoder.Save(FStream);
FStream.Flush();
FStream.Close();
}
--------------------------------------------
UPDATE:
Allright so i've been trying to solve this for days now and god knows the person going to help me is directly going to heaven! Anyway i found that i'm not able to fire any event handlers related to MediaPlayer or my thumbnail.cs (which is hosted in app_code and called by a asmx webservice).
Tried some workarounds by using threads and implementing my own made event handlers checking whether movie is loaded or not.. no luck there either MediaPlayer doesn't let me touch its insides in another thread... And i didn't want to do more hack approach while able to solve with an easy event handler!
Searched the deepest google, found a thread on 2006 that a person assumed it may be a problem with x64 (well i'm using x64) but i couldn't found anything about that on msdn and hell its been 5 years!
So to sum up, i'm probably having a massive event not firing problem with either my class or my MediaPlayer control. And i need a saviour to help me catch the mediaOpenned event..
Thank you again.

Flash: How to dispatch a click event at the top of a loaded .swf?

So I'm trying to build a tool that will allow me and other users to all open the same .swf, and then I as the Admin user am able to interact with mine while they all see my mouse movements and button clicks etc on theirs.
I'm using BlazeDS to manage this and I'm getting data sent back and forth etc - no difficulties there. The issue I'm running into is this:
In an "Admin" instance, I click a button. I capture that X and Y, then tell Blaze to tell my clients to dispatch a Click event at that X and Y. On my client side, I get that data and dispatch a Click event at that X and Y - but the click is actually caught at the stage level. The click on my client side takes place UNDER all of my buttons and other content - so the whole thing fails.
Does this make sense? Is there a way to tell it to start the click event at the top?
If you are unable to architect the loaded swf's to use a better architecture you could try something a little more hackish to get buttons working.
Have a look at the methods getObjectsUnderPoint and areInaccessibleObjectsUnderPoint of the DisplayObjectContainer. Combined with hasEventListener you should be able to emulate what you want.
Here is some untested pseudo-code:
function detectClick(pt:Point):void
{
var objsUnderPoint:Array = containerStage.getObjectsUnderPoint(pt);
var clickable:Array = [];
for each(dispObj:DisplayObject in objsUnderPoint)
{
if(dispObj.hasEventListener(MouseEvent.CLICK))
{
clickable.push(dispObj);
}
}
if(clickable.length)
{
// sort on depth here
// that might be tricky since you'll be looking at grandchildren
// and not just children but it is doable.
var topMostClickable:DisplayObject = ???
topMostClickable.dispatchEvent(new MouseEvent(MouseEvent.CLICK, true, false));
}
}
areInaccessibleObjectsUnderPoint is important if you think their might be security restrictions (e.g. cross-domain issues) so you can debug if things go wrong.
Also note that you may want to (or need to) fill in more details of the MouseEvent (like the proper target, localX, localyY etc.)
Sounds like you need to set focus to the top most component of the x and y positions before dispatching the click event.
That said, I wonder what the use case is for something like this; as opposed to using a screen sharing tool such as Connect.
This seems like a poor way to implement what you are trying to do. If you "click" in the admin tool you are probably actually triggering some event. Why not trigger that event instead of sending the mouse click?
I'd just keep a map of actions and then when something happens in the Admin interface send the key to the action.
e.g.
In the admin:
myButton.addEventListener(MouseEvent.CLICK, handleClickButton);
function handleClickButton(event:MouseEvent):void
{
doSomeAction();
sendTriggerToClient(MyActions.SOME_TRIGGER);
}
In the client:
var actionMap:Object = {};
actionMap[MyActions.SOME_TRIGGER] = doSomeAction;
function receiveTriggerFromAdmin(trigger:String):void
{
var responseFunc:Function = actionMap[trigger];
responseFunc();
}
I hope that pseudo-code makes sense. Just abstract what happens as a result of a click into a separate function (doSomeAction) and then have the admin send a message before calling that function. In the client wait for any trigger that comes through and map it to the same function.

Forcing Flex to update the screen?

This may be a bit of a beginners question, but I can't for the life of me figure it out.
I'm using flex to develop a GUI for a large project, specifically a status bar along the bottom. Within my StatusBar class is a ProgressBar, which other classes doing work can tell to update(change bar completion and label) as they progress. The problem I'm encountering is that flex won't update whats shown on the screen until it's too late, for example
ProgressBar initialized, 0% done
some class sets the ProgressBar to be 12% done
some class does some work
some class sets the ProgressBar to be 56% done
Whats happening is the 12% done is never displaying, it just hangs at 0% during the work, then skips right to 56% done. I've tried to understand the lifecycle of a flex component (invalidation and validation), and I think I understand it and am applying it correctly, but it's not working at all. I need to tell flex to redraw my StatusBar (or at least the ProgressBar within) after some class sets it to be 12% done, but before some class starts doing its work. How do I do this?
As mentioned in other answers, the flash player is single threaded, if you don't break up your work into discrete chunks that can be executed in separate "frames", you're going to see jumps and stutters in the ui, which is effectively what you're seeing.
If you really must see that 12% message, then it's not enough to invalidate the display list, as the display list isn't getting a chance to update until after the 56% work has completed, you must explicitly interrupt the natural event cycle with a call to validateNow() after your message has been set.
This however is not the best way to do things if performance is of concern. You might get by with judicial usage of callLater() to schedule each chunk of work in turn, as this will allow the player to potentially complete a frame cycle (and update the display list) before attempting the next step in your process.
Glenn,
That is not at all how the threading in Flex works whatsoever. Like many UIs it has a message pump on the main UI thread (they do it in frames). When you call callLater() it places the passed in function pointer at the end of the message pump queue (on the next frame) and returns immediately. The function then gets called when the message pump has finished processing all of the messages prior (like mouse clicks).
The issue is that as the property change causes UI events to be triggered, they then place their own messages on the pump which now comes after your method call that you placed there from callLater().
Flex does have multiple threads but they are there for Adobe's own reasons and therefore are not user accessible. I don't know if there is a way to guarantee that a UI update will occur at a specific point, but an option is to call callLater a number of times until the operation occurs. Start off with a small number and increase until the number of iterations produces the result you want. Example:
// Change this to a number that works... it will probably be over 1, depending on what you're doing.
private const TOTAL_CALL_COUNT:int = 5;
private var _timesCalled:int = 0;
//----------------------------------------------------------------
private function set Progress( progress:int ):void
{
progressBar.value = progress;
DoNextFunction();
}
//----------------------------------------------------------------
private function DoNextFunction():void
{
if( _timesCalled >= TOTAL_CALL_COUNT )
{
_timesCalled = 0;
Function();
}
else
{
_timesCalled++;
callLater( DoNextFunction );
}
}
Try calling invalidateDisplayList() after each changes to your progress bar. Something like :
Class StatusBar
{
public function set progress(value:uint):void
{
progressBar.value = value;
progressBar.invalidateDisplayList();
}
}
Flex has an invalidation cycle that avoid screen redrawing everytime a property changes. As an example, if a property's value changes 3 times in a single frame, it will render only with the last value set. You can force a component to be redrawn by calling invidateDisplayList() which means updateDisplayList will be immediatly executed instead of waiting the next frame.
Actionscript in Flash player, like Javascript in the browser, is pseudo-multithreaded. That is, they're single threaded, but they have multiple execution stacks. This means you can't "sleep" in a particular thread, but you can spawn a new execution stack that gets deferred until a later time. The flex way of doing this is the "callLater" function. You can also use the setTimeout/setInterval functions. Or you can use a timer object built into the flash player. Or even "ENTER_FRAME" event listener. All of these will essentially allow you to do what you need, if I'm correct about the cause of your problems.
It sounds like you have one "thread" doing most of your work, never stopping to allow other execution stacks (threads*) to run.
The problem could be what PeZ is saying, but if that doesn't help, you might want to try some deferred calls for worker classes. So your process might look like this now:
Progress initialized.
Do some work.
Update progress bar to 12. (invalidate display list)
setTimeout(doMoreWork, 100);
Update progress bar to 52.
(if your worker is a UIcomponent, you can use uicomp.callLater(...), otherwise, you need to use setTimeout/timers/enter_frame for pure AS3 classes).
Sometimes its necessary set to zero before assign another value.
progressBar.setProgress(0, progressBar.maximum);
progressBar.setProgress(newValue, progressBar.maximum);
I'm using Flash Builder 4.6 and I also have a problem for the display of my progress bar. I open a new window where I start a new multiloader class (39 Mo of content). The new window is opened in background and the main window display a progress bar until the multiloader class has finished his work. However the opening window is blocking the animation of my main window. I know it's not the multiloader class cause I saw it running correctly.
But I will try to find some new ways of doing it.
The main purpose of my post is the complexity adobe has build around flash.
When you seek ressources for your own application or answers for your questions, it's a real pain to find the good ressource. There is a total mix up (at adobe side and at user side) between AS3, Flex, Flash CS, Flash Builder, AiR, ... If you try to develop in AS3, you will find that some examples won't work for you because it is not implemented in your SDK. You have more and more forums giving you the "best practice" or ironic answers based on experiences on different developping platform.
By example, just here above, I see progressBar.value = value; With my experience, I can say that in Flash Builder 4.6, this property is read-only. But It might be a custom class made by the user but who can tell.

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