Codenameone: Query regarding to suspended mode - codenameone

we want to start application from initial stage when we put it in suspended mode or minimize it.currently when i minimizing application it starts from screen where i left or application starts from that screen the screen which present at the time of minimizing application.
we just want to start application from initial state or specific screen when we minimize it or we put it into suspended mode.
Can you please let me know how to resolve it. My application needs to be supported on all platforms (Android, iOS, Windows) and I don't want to write native code for all platforms separately.

When an application is minimized we call stop() and when it's restored we call start() again. Just remove the boilerplate code that calls current.show() in the start() method and state won't be restored.

Related

How to activate system idle state of Windows?

I am working on a C application which runs in the background without any Windows control.
I want to put Windows in a system idle state as if the screen saver is enabled and the ScreenSaveTimeOut value is reached.
I can simulate the desired behaviour to some extent by using SystemParametersInfo with SPI_SETSCREENSAVERACTIVE and SPI_SETSCREENSAVETIMEOUT=1 parameters.
Unfortunately, this requires me to use a screen saver.
Are there any APIs available which I could use in order to put Windows directly in an idle state?
Thanks in advance.
Maybe SetSuspendState or SetSystemPowerState are what you are looking for.

Embedding CEF3 with existing application

I have a running WIN32 application. There a window in this application where I want to show web content using CEF3. But, I am facing problems and the entire window becomes white without showing any web page content. So I have the following questions:
Is it possible to use CEF3 with existing message loop in application? I dont want to call the CEF message loop, it may impact other things in my application.
Is it absolutely necessary to use a message window as in the sample application? I am not able to understand its objective.
When CEF3 launches multiple processes, how does it show in the task manager? If my application name is A.exe, does it show A.exe multiple times in task manager?
Any help is much appreciated.
For windows users there is possible to use multi threaded message loop (CefSettings). It is allow maintain browser windows via own message loop. But there is good practice use single threaded message loop, - you can call CefDoMessageLoopWork periodiacally on idle or some additional events. It is possible even with existing message loop.
I'm not sure what you mean.
CefSettings.BrowserSubprocessPath specifies which executable will be used for child processes. While you are integrating it in other process, looks like it is one possible solution and in task manager you will see processes as you named it.
About the question number 2:
every windows application has its own "main window" and wndProc that receives all the messages sent by his children.
And the sample win32 cefclient shows how to integrate cef message loop inside the application's message loop.
And if you don't handle and dispatch cef messages in proper way the browser window becomes white.

Application.Dispatcher.UnhandledException and CurrentDomain.UnhandledException

I'm investigating strange WPF multi threaded application hang that happen randomly on production machines more easily than development ones.
I have added Application.Dispatcher.UnhandledException and CurrentDomain.UnhandledException event handlers to log the every and each exception in order to keep the application from crashing as it is a system shell.
I suspect the reason of the hang is that I'm handling those events and not allowing the application to crash, what make me say this is that when i monitored the application activity when it hanged using windows task manager i noticed CPU load probably caused by background tasks in the application and those background tasks are writing to logs as expected.
The logger class writes the logs to the disk asynchronously using BeginInvoke.
The big problem is every time the application hangs in production machine i find nothing in log files.
Now i have two questions:
What is the fire order of those events: "Application.Dispatcher.UnhandledException and CurrentDomain.UnhandledException".
2.Is there anyway i can manage to be able to know were my code is failing
Note: I use a lot of Thread.Sleep in background tasks as i manage the threads my self and i think i went wrong with this approach and I'm considering rewriting all of my background tasks from scratch.
Any help will be much appreciated.
Order of this event is:
Application.DispatcherUnhandledException
CurrentDomain.UnhandledException
If you want get information from exception where your code is failing, check property StackTrace. You can also attach to your project pdb files and in this case you will get StackTrace with line numbers.

Avoiding all system messages and messages from other software

Here is the situation. The company I work for builds this piece of software in c that can make a Windows computer act a bit like a TV. Essentially, our piece of software is meant to be played full screen and content is displayed from the internet without the user having to ever touch the computer again.
The problem is that once in a while, the system brings up pop-ups like "Your Windows system is ready for an upgrade." or "Please renew your Norton subscription" etc. which the user has to periodically and manually remove.
Is there a way to display content full screen without being bothered by those warnings?
Yah, whether or not the development community agrees, Microsoft has several standards for when and why it might be acceptable to have exclusive use of the monitor.
The most official strategy is to use DirectX in exclusive mode. This is what games do, what windows media player does in full screen video with hardware acceleration enabled, etc... If your application is multimedia intensive (as suggested by TV like functionality), you should probably be using DirectX too. Besides giving you the exclusive display access it will also increase your applications performance while lowering the CPU load (as it will overload graphics work to the video card when possible).
If DirectX is not an option, there are a great number of hacks available that seem to all behave differently between various generations of windows operating systems. So you might have to be prepared to implement several techniques to cover each OS you plan to support.
One technique is to set your application as the currently running screensaver. A screensaver if really just an EXE renamed to SCR with certain command line switches it should support. But you can write your own application to be such a screensaver and a little launcher stub that sets it as the screensaver and launches it. Upon exit the application should return the original screensaver settings (perhaps the launcher waits for the process to exit so that it returns the settings in both graceful exits and any unplanned process terminations ie: app crash). I'm not sure if this behavior is consistent across platforms though, you'll have to test it.
Preventing other applications from creating window handles is truly a hack in my opinion and pretty bad one that I wouldn't appreciate as a customer of such software.
A constant BringWindowToTop() call to keep you in front is better (it doesn't break other software) but still a little hack-ish.
Catch window creation messages with a global hook. This way you can close or hide unwanted windows before they become visible.
EDIT: If you definitely want to avoid hooks, then you can call a function periodically, which puts your window to the top of the z-stack.
You could disable system updates http://support.microsoft.com/kb/901037 and remove the norton malware.
You could also connect a second screen so that the bubbles appear in the the first monitor.
Or you rewrite it for linux or windows ce.
One final option is to install software that reconfigures your os into a kiosk http://shop.inteset.com/Products/9-securelockdown.aspx
If you don't need keyboard or mouse input, how about running your application as a screensaver?
A lot of thoses messages are trigged/managed by Windows Explorer.
Just replace it with your dummy c#/winform.
By changing the registry value
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
"Shell"="Explorer.exe"
You can specify virtually any exe as an alternative to explorer.exe
That's the way all windows based (embedded) system (ATM & co) do.
There's still few adjustment (disable services you dont need / dr watson & others), and of course, you'll want to keep a "restart explorer.exe" backdoor.
But that's a good start

How to debug and detect hang issue

I am testing my application (Windows 7, WinForms, Infragistics controls, C#, .Net 3.5).
I have two monitors and my application saves and restores forms' position on the first or second monitors. So I physically switched off second monitor and disabled it at Screen Resolution on the windows display settings form. I need to know it is possible for my application to restore windows positions (for those windows that were saved on the second monitor) to the first one.
I switched off second monitor and press Detect to apply hardware changes.
Then Windows switched OFF the first monitor for a few seconds to apply new settings. When the first monitor screen came back, my application became unresponsive. My application was launched in debug mode, so I tried to navigate via stack and threads (Visual Studio 2008), paused application, started and did not find any thing that help me to understand why my application is not responsive. Could somebody help my how to detect the source of issue.
Download the Debugging Tools For Windows then run adplus in hang mode. The with the resulting .dmp file open in windbg and invoke:
!analyze -v -hang
You should provide more information about what you saw in the call stack and threads windows. Which threads were running? Did you see anything that was waiting in a sleep or join? Have you tried naming your threads so that it's clearer as to what's going on when you pause (though not necessary since you can get this info from the call stack anyway... it's a convenience thing).

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