I am developing a GUI application in Qt 4.8.4 with Visual Studio 2010. I need to perform some cleanup work before my application closes so I have reimplemented the QWidget closeEvent in my MainWindow class to capture when the user either clicks X or when they select File->Exit from the menu. That works fine. The problem however is when I am running the application in the VS debugger and I use the debugger to shut down the application the close event doesn't get triggered. I can always just shutdown my application by clicking File->Exit or clicking X but sometimes I forget and shut down the debugger instead so it's really more of an annoyance. Is there a way to capture when the debugger shuts down my application?
Not that I know of.
The logic of it: the debugger is running a sandbox, and when it shuts down, the sandbox gets freed. Your application is running inside that sandbox - so when that sandbox gets freed/closed/destroyed, your app simply vanishes without any cleanup.
Related
got a weird question which I haven't been able to find an answer to online so I'm trying my luck here.
I have a normal erlang application using wxWidgets, once I try to shut down my application I get the event that the wxServer has indeed entered the event which is connected to the window closing, I get a message that it is in the process of exiting, and my window does indeed close, but as shown in the picture below, the beam.smp on my toolbar doesn't close at all, I have to manually force the closing of the beam.smp file which sends a SIGTERM to the erlang terminal which also shuts down my erlang VM (which I have to reboot it later).
long story short, what am I missing on my close window event so that everything shuts down nicely without it crashing my erlang VM? I was able to read that wxWidgets behaves differently on macOS but I haven't been able to find how to correctly close the application.
handle_event(#wx{event = #wxClose{}},State = #state{frame = Frame,panel = Panel}) ->
io:format("Exiting~n"),
wxFrame:close(Frame),
wxFrame:destroy(Frame),
wx:destroy(),
{stop,normal,State};
You can close the emulator from code with init:stop/0,1
Also, if your application is started as permanent, it should suffice with terminating that application. Check the behaviour in erlang:application
I have written file picker code in my project. When i run the project in my windows phone by clicking on device button in visual studio, the app runs fine(I mean it opens pictures library and i can select a photo and preview it).
But when I disconnect my usb and then open the app in the phone and when i open pictures library on click of a button , the pictures library opens briefly and then the app crashes immediately(My app closes).
Can anyone please help me with this??
As written in the blog post , the AndContinue method run in a different process and to do so, the current running app goes into the background or even gets closed sometimes, that is what you are experiencing in your app as far i can tell but not sure why different things happening during debug & deploy.
There must be a callback inside app.xaml.cs specifically to handle the condition when calling application(which was sent into background) comes in foreground, read this blog post carefully & you'll understand as what you need to change in your code :
using-the-andcontinue-methods-in-windows-phone
http://blogs.msdn.com/b/wsdevsol/archive/2014/05/08/using-the-andcontinue-methods-in-windows-phone-silverlight-8-1-apps.aspx
I just dealt with this issue and one of the reasons why there are differences between debug and deploy is because of the suspending event.
During debug, the application does not actually get suspended until you manually do it through Lifecycle Events. This means that when you pick a file on debug and the app is put to the background to load the file picker, it is not actually suspended, while when the app is deployed, it actually gets suspended.
Look into your app_resuming method and OnSuspending methods in your app.xaml that may be causing errors not occurring during debug.
I have a program in Windows CE 5.0 created in Visual Studio 2008. Opening the application I created works fine but when I close the application with:
Application.Exit()
I cannot open another application, I cannot even open the same application again.
Any idea what about closing the program properly? I have also tried using
Me.Close()
or
Environment.Exit()
cannot open another application, I cannot even open the same application again.
Looks like your application does not exit and 'blocks' the GUI. Or what exactly does the above mean? Can click the start button and a menu opens?
If your app uses background thread, the app will not close correctly until these threads are terminated too. You will have the app still in the process list but no GUI, the app seem to have terminated but it did not.
If you have background threads you have to terminate them BEFORE you Exit the application.
Background threads can be terminated using Thread.Abort() or using a condition in a while loop. For the thread.avort you have to code the lines of the background thread within a try/Catch block and catch for the ThreadAbortException.
I have a simple Windows Phone 7 application which is working perfectly when started from Visual Studio. However, if I deactivate the app (press Windows button or back button from the application's MainPage) and then click the app's icon to relaunch, the screen will flash and return to the list/home screen. I assumed this was an issue with the emulator but when I got a developer device I have the same issue.
Note that reactivating without a complete tombstone works (pressing Windows button from the app and then back).
I have no idea what causes this or how to proceed with debugging. Hopefully someone else has experienced this and knows a fix.
Turns out there is a bug, i found the solution here http://forums.create.msdn.com/forums/p/67522/416995.aspx
In short, it turns out that the Microsoft.Xna.Framework.Media.MediaLibrary class (which I am using to display pictures on applications main page) is not properly initialized when the user has not opened a media hub prior to you calling it. So picture collection properties are null or empty. The solution is to add a call to MediaPlayer.Queue.ToString(), it will force the initialization of the native media library allowing you to invoke the MediaLibrary later on.
Sounds like an unhandled error on startup is causing the app to crash.
Trap/log/handle/display any unhandled exceptions. Also check what you're doing on startup.
IF you are saving something (to Isolated Storage) after first run and then opening it on subsequent launches then that's where I'd look first.
If it works when launched from Visual Studio then this will probably be due to the way you are rebuilding/redeploying the app before launching it in that case.
I hava a web app running on a local tomcat server.
When the user starts the app (via desktop shortcut) the server starts and the app is opened in a browser window.
But when the user just clicks on the close button to stop the application the server is still running in the background - that's annoying.
I tried to utilize the "unonload" and "onbeforeunload" events from javascript but unfortunately these events are also fired on some other requests in the app.
So I can't use them, except I do a lot of refactoring.
Does anyone have an idea for a possible solution?
Btw, what I find interesting is the behaviour of Visual Studio when debugging a web application. When I close the browser window Visual Studio also gets a trigger to stop debug mode. So it seems it somehow notices the close event of the browser window, which would be exactly what I need. But I don't know how they do it...
Can you wrap the starting of Tomcat and launching your app in a batch file or shell script? (Not sure what your target OS is...)
The script/batch file would start Tomcat and then launch your application. When the user exits your application, the script/batch file would then shut down Tomcat.
You can setup a short session timeout, and use a HttpSessionListener. On sessionDestroyed(..) you can stop tomcat (using catalina.bat for example) .
Otherwise you can try to detect browser close, and send a shutdown message to the server using ajax (before the browser is closed).