Re: [Tutor] get key value from Redis instance
Thank you Danny, indentation and separation of code worked out as you mentioned :) Have a nice day! On Mon, May 28, 2018 at 12:14 AM, Danny Yoo wrote: > > From a first glance: it looks like one of your print statements is not > > vertically aligned with the rest of your print statements, so I would > > expect Python to be reporting a SyntaxError because of this misalignment. > > Substitute the word "vertical" with "horizontal". Sorry: I made yet > another mental typo there. :P > ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Tkinter widget (label) updated by TCP/IP message
On 28/05/18 19:56, Alejandro Chirife via Tutor wrote: > Two questions: > 1. ... How do you send an event of data arriving > when the events for tkinter are all about user interaction? The easiest way is to set a global variable and use a timer event (after()) to poll the variable periodically and update the UI. The downside of this is that you could miss an event if they arrive faster than the timer fires. If you only have a single background thread running you can just call the event handlers directly, but it gets iffy when you have multiple threads trying to do updates at the same time. Or if you can do manual updates via the UI - but I don't think that's an issue here. Most GUIs also allow you to create an event object and insert it into the main event queue. In Tkinter its the event_generate() command. I confess I've never had to use it but here is a stackoverflow simplified example: https://stackoverflow.com/questions/270648/tkinter-invoke-event-in-main-loop This is the purest solution that lets the GUI mainloop take care of all the sequencing conflicts implicit in the other options. > 2. You mentioned " create thread to run get_network_message" > in your pseudocode (in main() ). > Could you guide me towards which Class to > use for this? Check out the threading module in the standard library and its documentation. There is also a very simple example in my tutorial in the "Concurrent Processing" topic. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Tkinter widget (label) updated by TCP/IP message
On 05/28/2018 12:56 PM, Alejandro Chirife via Tutor wrote: > Hi Alan, > Thank you very much for your help. I will start working on ti. There's a > lot to chew on here :) > Two questions: > 1. Got it that nothing to do when mainloop() gets called. How do you send an > event of data arriving when the events for tkinter are all about user > interaction? > 2. You mentioned " create thread to run get_network_message" in your > pseudocode (in main() ). Could you guide me towards which Class to use for > this? > Thanks!AC You're going to want to look at the threading module for threads, and the socket and the select modules for networking. threading.Event and threading.Timer may be of interest as to communicating with the other thread and setting a timeout. This isn't actually as trivial a problem as it may sound on the surface, by the way, so don't worry if it takes a while to get right! ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Tkinter widget (label) updated by TCP/IP message
Hi Alan, Thank you very much for your help. I will start working on ti. There's a lot to chew on here :) Two questions: 1. Got it that nothing to do when mainloop() gets called. How do you send an event of data arriving when the events for tkinter are all about user interaction? 2. You mentioned " create thread to run get_network_message" in your pseudocode (in main() ). Could you guide me towards which Class to use for this? Thanks!AC On Sunday, May 27, 2018, 1:04:22 PM EDT, Alan Gauld via Tutor wrote: On 27/05/18 16:18, Alejandro Chirife via Tutor wrote: > > Hi all, I am having a hard time to create what at first looked like a simple > program with Python 3 and Tkinter: > The UI consist of a window with a label and a button. > The label shows "waiting for a message" and the button shows "reset display". > > The handler for the button click just resets the label text to "waiting for a > message". So far so good, it is all standard Tkinter programming but > The program would draw the window with the two widgets with root.mainloop()> > while it is capable of listening on a TCP port for an arriving message This is not so good. You can't do anything in your code after you call mainloop(). Thats just the nature of event driven programming. Once mainloop() is called all control rests with the GUI and you can only respond to events. Sooo > like "hello world", and when it arrives it would show the text in the label. > You need to put your network listener in a separate thread started before you call mainloop(). Then when a message is received you need to generate an event in your Tkinter GUI (or you could just call an event handler directly but that's considered bad practice (for some good reasons!). > The received message should show in the label until any of the following > occurs: > > - Has been shown for 10 seconds Set a timer in the GUI that expires after 10 seconds - Another packet arrived with new message (will show the new message in the label) Generate (or call) the same event as before but don't forget to cancel the current timer. - User clicks on the "reset display" button In the button event handler - Cancel the timer. - Display whatever the reset message says So in pseudo code you need: import tkinter as tk def button_click() cancel timer display default message def display_message(msg): display msg on label cancel current timer create new 10s timer def timeout(): display ??? def get_network_message() your network receiving code here if is_valid_message(msg): display_message(msg) def main(): create GUI bind events create thread to run get_network_message mainloop() HTH -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.amazon.com/author/alan_gauld Follow my photo-blog on Flickr at: http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
