This is my first try with PySimpleGUI.
I've written a simple window with three output fields:
Text
Output
Multiline
The window paints fine, and the default values display. But I can't get any of the fields to update.
Am I doing something stupid (almost certainly!)?
Here is the code and result:
Code
Display
Thanks in advance, Chris.
I've tried multiple field types and various options to try to force update, all to no avail.
Something wrong
sg.Window(...).read() not return window, but event, values. It also block the execution until an event happened. It looks the only event is to close the window, then the GUI cannot be updated after window destroyed.
window[key].update(...) return None, None don't have method read to call. Method update won't update the GUI, but the configuration in PySimpleGUI.
Should update the GUI in the event loop where the window.read called after any actions for specific event.
time.sleep(30) will get the GUI no response for 30 seconds.
I understand that in tkinter once mainloop() has been run, no code after it will run until the window has been destroyed. I have found that the common solution is to use tk.after to call a function repeatedly at certain intervals. However I am using a for loop, and every time it loops it updates a variable which I want to see change in the GUI.
PB=myProgressBar()
for i in range (0, len(dataset)):
performfunction
PB.update(i)
PB.quit()
The aim is while performing an operation on each item in the dataset, the GUI will show how far the program is.
Within my progress bar class I have tried using a tk.IntVar as my ttk.ProgressBar value and setting the value through the PB.update(i) to update it.
I have also tried using ProgressBar['value']=i in my update method of the progress bar class.
In both cases if i run mainloop() before the loop, the for loop doesn't run (as you'd expect) but I'm not sure how to run mainloop and get update the GUI without a messy tk.after function that would probably have to involve a self.i value (and then do self.i+=1 at the end of the function that replaces the loop).
Is there a clean 'pythonic' way to do this?
If I have used the place_forget command in order to hide a button when switching frames, how can I bring the button back at a later stage in the program? Or would I have to recreate it?
You will need to call place again. You do not have to recreate the widget as long as you keep a reference to the original widget.
How to suppress end user ability to edit/add/delete text in a Text widget? (Python v3.2.. and tkinter)
The point is to suppress only the ability to change/add/delete text but not to castrate other features. Perhaps a NoEdit Text widged would be a better name.
I've tried .text['state'] = 'disabled' and it works almost OK in Windows (it still allows user to select/copy text highlights the selection, page up/down and up/down buttons work. The only thing broken seems to be the cursor made invisible.)
But on MacIntosh everything is broken. No highlights, no select/copy,... UGH
Since Tkinter has practically no documentation in Python, I've searched and found some TCL advise, to derive a new class and suppress the insert and delete functions.
So, I've tried as so:
class roText(tk.Text):
def insert(self,*args,**kwargs):
print(" Hey - Im inside roText.insert")
pass
def delete(self,*args,**twargs):
pass
def pInsert(self,*args,**twargs):
super().insert(*args,**twargs)
Unfortunately it didn't work right. Apparently tkinter does not use those insert and delete functions when end user enters/deletes code. Perhaps those TCL insert/delete are something else, and I lost something in translation from TCL and Swahili. What functions does tkinter.Text use for end user editing text? Hopefully they are not internal...
So, is there a way to modify the Text widget to suppress only end user editing?
Is there a way to do it without diving inside and overriding internal Tkinter code, so the stuff doesn't get broken by next releases of Tkinter?
Looking at the Idle shell window, I see that they've managed to suppress edits (except for the last line). So there is a way. But what is it and how costly?
Sorry for bumping an old question, but I was searching for an answer to this question also and finally found a solution. The solution I found involves overriding the key bindings when the text widget has focus and is pretty simple. Found here.
To override the bindings of a widget there is a bind function where you pass a string of what is to be overridden and the new function you want it to call.
self.txtBox.bind("<Key>", self.empty)
Somewhere else in the class you'll need to define the function to handle the event.
def empty(self, event):
return "break"
By returning the string "break" the event handler knows to stop after your function, instead of continuing with the default action.
I hope this answers your question. Cheers.
The reason the disabled state doesn't seem to work on the Mac is because it turns off the binding that gives focus to the widget. Without focus, the highlighting on a Mac doesn't show up. If you set the state to disabled but then assign a binding to <ButtonPress-1> to explicitly set focus to the disabled text widget, you can then select and copy text and the highlighting will show.
As for the cursor disappearing... arguably, that's what's supposed to happen. The cursor tells the user "this is where text will get inserted". Since no text will get inserted, having that visual clue would be confusing to the user. What you could do instead, if it was really important, is to insert a small image wherever they click to simulate the cursor.
To answer your question about whether the widget actually uses the insert and delete methods: the methods on the actual underlying widget are what the default bindings use, so overriding them in a subclass has no effect. You would need to redo all the default bindings for that to work. It's doable, but a lot of work.
Unfortunately, this is one area where programming in Tcl really shines, because you can simply disable the insert and delete commands of the widget. Of course, you can do that directly in Tkinter also since ultimately it runs tcl code to do everything, but that would involve writing some tcl code which is not a very good solution from the perspective of a Python coder.
I think the best solution is to use the disabled state, then add in just enough bindings to do what you want.
Here's a simple example that works by explicitly setting focus on a mouse button click. With this code I'm able to click and swipe to select a region, or double- or triple-click to select words and lines:
import Tkinter as tk
class SampleApp(tk.Tk):
def __init__(self, *args, **kwargs):
tk.Tk.__init__(self, *args, **kwargs)
self.text = tk.Text(width=40, height=20)
self.text.bind("<1>", self.set_focus)
self.text.insert("end", "\n".join(dir(tk.Tk)))
self.text.configure(state="disabled")
self.text.pack(fill="both", expand=True)
def set_focus(self, event):
'''Explicitly set focus, so user can select and copy text'''
self.text.focus_set()
if __name__ == "__main__":
app = SampleApp()
app.mainloop()
#BryanOakley It took me a while to test your suggestion since I have no Mac.
Unfortunately Mac implementation of Python is buggy.
I've added focus, ie my disable function which I call after creating a window and inserting text, now calls first:
self.txt['state'] = 'disabled'
and then
self.txt.focus_set()
Which is what I think you've suggested.
It "kind of" worked. Ie: when selecting text (click and drag or double-click) highlighting works most of the time. Python must have some bad memory references or such bugs: Sometimes highlighting doesn't work at first, then it starts working (in the same window) after more clicking. Sometimes when program is invoked it works right of the bat. Sometimes selecting with Shift-rightArrow key will work but selecting with the mouse will not. Then starts working again. Or it will work fine in one window but not in another one (both of the same class), then starts working in all windows...etc...
The good thing is that adding focus did not affect badly Windows (ie all works fine as without focus.
I guess at this point I will just hope that future/next release of Python for Mac will fix those bugs..
BTW, it seems that Mac is a bit of an orphan for Python. Implementation is much uglier then for Windows. I mean the fonts look worse, the buttons, etc.. Or it could be due to different screen resolutions and Python ports that poorly account for those. Not sure
Anyway. Thank you for your help and suggestion to use focus for Mac.
I have a wx.ListBox in a python program, and I wan't to change out the list in it on a wx.Timer update. I have the timer working, I just don't know how to change out the list that it displays.
Here's an example for modifying a ListBox.
Generally, it uses the Append and Clear methods of ListBox. You can call those in your timer handler.
Since ListBox derives from ItemContainer, see more item modification methods here.