So I have been pulling my hair out all day at this, and I am out of patience.
Basically I have a pygtk program that is built from glade. At the bottom of the main window, there is a status bar that I use to display usage errors, and status messages about the connected hardware and they use the functions below. So all of the calls to displayError come from within my object based on user interaction, and they all seem to work. In testing I tried making calls to displayCurrent and it works as well. The problem comes when the hardware process tries to use displayCurrent. The way the system works is that one of the members of my main window class is an interface object to the hardware. This has a separate process, using multiprocessing.Process, which sends a signal every time it gets data with the data being the message to output. Does anyone have any ideas? I'll be happy to explain anything in more depth if needed, it's just a LOT of code to post to get all the details.
def displayCurrent(self, message):
print message
if self.lastMess:
self.statusBar.remove(self.normalID, self.lastMess)
self.lastMess = self.statusBar.push(self.normalID, message)
def displayError(self, message, timeout = 5):
"""
Function that takes an error message and raises it to the user via the statusbar
timeout seconds later.
"""
print message
mess = self.statusBar.push(self.urgentID, message)
# clear statusbar
gobject.timeout_add_seconds(timeout, self.clearStatus, self.urgentID, mess)
def clearStatus(self, cID, mID):
#time.sleep(timeout)
self.statusBar.remove(cID, mID)
#print self.statusBar.remove_all(self.urgentID)
print 'popped'
return False
Post the whole code.
In general, this won't work if you are in a separate process. GTK (and everything else) has been forked. You need to use some form of interprocess communication. Multiprocessing module handles it for you. There are also hacks you can do in GTK such as using a window title (like Vim) or perhaps a plug and socket to communicate; don't be tempted by these.
Related
I have a C++ program that I used this simple gtk code at first of my main() function, and my goal is my app shows an image when it started and keeping showing the image and keep the rest of program.
GtkWidget* window;
GtkWidget* image1;
GtkWidget* image2;
gtk_init (NULL,NULL);
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
image1 = gtk_image_new_from_file("1.jpg");
image2 = gtk_image_new_from_file("2.jpg");
window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
g_signal_connect(G_OBJECT (window), "destroy",
G_CALLBACK (destroy), NULL);
gtk_container_add(GTK_CONTAINER (window), image1);
gtk_widget_show_all(window);
gtk_main();
THE REST OF PROGRAM THAT WONT EXECUTE!
But when it opens a window and shows the image, it stuck there and doesn't execute the rest of code! Why this happens?
After you execute gtk_main, your code will "block", if i can say that, in that line until gtk_main_quit it's called/executed.
This is the nature of graphical user interfaces. Typically, you setup everything, call the main loop and wait for user interaction.
I would suggest that you read GNOME's Getting Started with GTK+.
As an example, if you do any printf below gtk_main, it will get printed after you close the GtkWindow.
Your application logic must be defined previously, then by means of user interaction, pressing buttons and other widgets, the application will do "things".
When you call gtk_main, the main loop starts.
The main event loop manages all the available sources of events for
GLib and GTK+ applications. These events can come from any number of
different types of sources such as file descriptors (plain files,
pipes or sockets) and timeouts.
You can read more about it here.
I made a code through python to operate a preview of my PiCamera, I have set the time to 10 seconds, then automatically turns off. However I am unsure how I would be able to have a keystroke to stop the camera and return to the previous screen?
At the moment I am able to view for 10 seconds, and nothing else, the usual ctrl-c and various other keys does not work.
How would I be able to integrate a keystroke into the code following to stop the script and return to normal screen?
from picamera import PiCamera
from time import sleep
camera = PiCamera()
camera.start_preview()
sleep(10)
camera.stop_preview()
Subprocess module you can check on the official page:
https://docs.python.org/2/library/subprocess.html#subprocess.Popen
A possible way to implement with subprocess.Popen is here on SO:
Controlling a python script from another script
Another possibility is to use multiprocesses or multithreading module. For instance creation of a thread can be done and you can take care of an ID :-)
All the possibility will lead you to learn a bit more of python!
My better suggestion will be to create easily a thread (https://docs.python.org/3/library/threading.html --> here for python 3), get the ID and leave it run.
If you want to terminate the camera running, then terminate the thread :-)
I'm writing a small custom player based on libvlc. I've used much of the code from https://github.com/hartror/python-libvlc-bindings/blob/master/examples/gtkvlc.py that plays a single track just like I need.
Now I want to swtich to another track after previous has finished. To do that I catch callback "EventType.MediaPlayerEndReached" and in callback handler I write code:
<------>def endCallback(self,event):
<------><------>fname = vlc_controller.GetNextTrack()['url']
<------><------>self.w.set_title(fname)
<------><------>self.vlc.player.set_mrl(fname)
<------><------>self.w.set_title('after set_mrl')
<------><------>self.vlc.player.play()
<------><------>self.w.set_title('after play')
Now when this code gets executed it stucks on self.vlc.player.set_mrl(fname) and does not go any further and as a result I see NO NEXT TRACK.
I've tried different variations of this code using (vlc.stop(), vlc.set_media instead of vlc.set_mrl) but nothing works
Finally....
I think the best choise is to make multi threaded application on python
2 Threads:
Main thread - gtk.loop and displaying video an some other thinks
Additional thread that makes media switching.
For some time I was afraid of multithreading but now I know that this was the best way to do this task
For those facing similar issue in C# (Xamarin), per VLC documentation, calling the VLC object from an event tied to the object may freeze the application. So they said to use the code below inside the trigger event.
ThreadPool.QueueUserWorkItem(_ => PlayNext());
An example would be calling the code above inside the EndReach event.
Where PlayNext() is your own custom method to handle the next action you want to execute.
I struggled with this for about a day before seeing that portion of the documentation.
I have console applicaiotn that currently uses CAsyncSocket.
I need to implement SSL so after some searching I found this project: http://www.codeproject.com/Articles/3915/CAsyncSslSocketLayer-SSL-layer-class-for-CAsyncSoc
For some reason same simple code that works fine on GUI code does not work in console app.
Has anyone exp. with CAsyncSslSocketLayer ?
Thanks.
CAsyncSocketEx uses a window as a sort of cheap thread to handle the event notifications that come from select(). Unfortunately, if you don't have a message loop, then the window which it creates will not receive these events.
http://support.microsoft.com/kb/90975
This article explains that a call to CreateWindow() needs to be called from a thread which has a message loop. And if you don't, then anything sent via PostMessage() won't get there.
I've recently started to tinker with this -- I want to remove the annoying hidden window and replace it with a normal thread. Their code relies on WSAAsyncSelect() in order to receive socket events... to a window. Yuk!
It's been a while since I had the same problem, but if I remember correctly, to use CAsyncSocket in a console app you need to add something like DECLARE_CONSOLEAPP (first two links shown below) to your console app. This should give your console a message pump to generate the socket notifications (OnReceive, etc.) GUI apps have these pumps but console apps don't, generally. The third (msdn) link below might also apply, it has more info and a different way.
If these still don't work, you should put breakpoints in your socket code and make sure your socket isn't instantiated in a thread or callback other than the main console app (the one that now has the message pump).
I think googling around for 'CAsyncSocket WinApp' or 'CAsyncSocket console app' would show more.
http://www.codeguru.com/cpp/misc/misc/consoleapps/article.php/c243/Console-app-using-MFC.htm
http://troels.knakkergaard.dk/code.htm
http://social.msdn.microsoft.com/forums/en-US/vcgeneral/thread/a6f1b72a-21d8-4046-a3dc-d7d29ece2ef6
Hi I would like to pause the execution of a function in an cocoa project. I dont want to use sleep() because the function needs to resume after user interaction. I also want to avoid doing this with multiple calls to sleep.
Thanks for your responses. Ok I started the code while waiting for some answers. I then realized that sleep or pause would not be usefull to me because it freeses my whole program. I think I might have to do some threading. Here is the situation:
I have a program that uses coreplot. I also use it to debug and develop algorithms so I do lots of plots while the data is being processed (ie in the midfle of the code but I need the flexibility to put it anywhaere so I cant separate my function). I was able to do this with NSRunAlertPanel but having a message box like that doesnt make it very presentable and I cant do much with the main window while an alert is open.
I hope I am not too confusing with my explanation but if I am ill try to one line it here:
I would like to interact with my cocoa interface while one of my functions is stopped in the middle of what it is doing.
Its sounds to me like you're looking for -NSRunLoop runUntilDate:
Apple's Docs: runUntilDate
This code will cause the execution within your method to pause but still let other events like timers and user input occur:
while ( functionShouldPause )
{
[[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:1]];
}
Switching functionShouldPause back to false will allow the rest of the method to execute.
It seems more like you are interested in reacting to user events rather than "pausing" the function. You would probably want to put the code that you want to execute into another function that is called as a result of the user's actions.
In C you can use the pause() function in <unistd.h>. This causes the calling program to suspend until it receives a signal, at which point the pause call will return and your program will continue (or call a signal handler; depending on what signal was received).
So it sounds like you want to break the function into two parts; the bit that happens before the sleep and the bit that happens afterward. Before going to sleep, register for a notification that calls the "after" code, and can be triggered by the UI (by an IBAction connected to whatever UI element). Now instead of calling sleep(), run the run loop for the period you want to go to sleep for, then after that has returned post the "after" notification. In the "after" code, remove the object as an observer for that notification. Now, whichever happens first - the time runs out or the user interrupts you - you get to run the "after" code.
Isn't there a clock or timer function? When your button is pressed start running a loop like timeTillAction = 10 and do a loop of timeTillAction = timeTillAction - 1 until it reaches 0 then run whatever code after the 10 seconds.
Sorry if this isn't well explained.