What are my options for getting validation with the Tkinter.Text widget? I don't require Text's advanced functionality, just its multiline attribute. Unfortunately, it lacks both textvariable and validate commands, so it seems that I cannot attach some kind of callback that checks things every time the text changes. I'd like to avoid having to bind to <KeyRelease>, as that looks to capture ALL keypresses, including the likes of Shift, Ctrl, etc, keys, and would appear to be a bit of a mess to work right.
I basically just need to check if the Text field is blank or not, and enable/disable an "Ok" button as appropriate (i.e., if no text, then the button is disabled).
In lieu of this, has anyone come across a decent subclass of Entry that adds multiline functionality that is written in Python? There is this, which adds textvariable to Text, but it is written in pure TCL, not Python, and seems like it would be difficult to integrate into my existing Python environment.
The binding to the <KeyRelease> button does not need to be messy, you don't have to check the value of the key pressed but fetch the content of the widget. Keep in mind that it always has a '\n' at the end, so when you retrive the contents don't forget to discard it:
content = text.get(1.0, "end-1c")
Then you just need to change the state of the button based on this value:
import Tkinter as tk
def configure_ok_button(event):
content = event.widget.get(1.0, "end-1c")
state = "active" if content else "disabled"
button.configure(state=state)
root = tk.Tk()
text = tk.Text(root)
button = tk.Button(root, text="Ok", state="disabled")
text.bind("<KeyRelease>", configure_ok_button)
text.pack()
button.pack()
root.mainloop()
Related
The question's in the title, essentially: how do I get the validatecommand callback to continue being called after setting the Entry's textvariable? Here's the Minimum Working Example (MWE):
import tkinter as tk
root = tk.Tk()
sv = tk.StringVar()
def callback():
print(sv.get())
sv.set('Set Text.')
return True
e = tk.Entry(root, textvariable=sv, validate="focusout",
validatecommand=callback)
e.grid()
e = tk.Entry(root)
e.grid()
root.mainloop()
Note that the second tk.Entry widget is there to allow the first one to lose focus, which is the event we're trying to capture.
As the code is now, when you run it, you can change the top Entry widget's text once. It'll correctly get set to Set Text. Then, if you try to change the Entry's text again, the new text will be in the widget, but the callback doesn't happen.
On the other hand, if you comment out the sv.set('Set Text.') code, this behavior completely disappears, and the callback gets called as many times as you wish.
How can I have the sv.set() functionality, while still maintaining the callback getting called every time the Entry widget loses focus?
This is discussed in the Tk manual page for entry:
The validate option will also set itself to none when you edit the entry widget from within either the validateCommand or the invalidCommand. Such editions will override the one that was being validated.
Presumably, this is done to avoid infinite recursion.
You can run this (instead of the given Tcl code, after idle {%W config -validate %v})
root.after_idle(lambda: e.config(validate="focusout"))
from the callback to schedule a reconfiguration of the widget to enable validation again (after changing your sources so that e is the right Entry widget, i.e. not the second one).
It doesn't look like it has that attribute, but it'd be really useful to me.
You have to change the state of the Text widget from NORMAL to DISABLED after entering text.insert() or text.bind() :
text.config(state=DISABLED)
text = Text(app, state='disabled', width=44, height=5)
Before and after inserting, change the state, otherwise it won't update
text.configure(state='normal')
text.insert('end', 'Some Text')
text.configure(state='disabled')
Very easy solution is just to bind any key press to a function that returns "break" like so:
import Tkinter
root = Tkinter.Tk()
readonly = Tkinter.Text(root)
readonly.bind("<Key>", lambda e: "break")
The tcl wiki describes this problem in detail, and lists three possible solutions:
The Disable/Enable trick described in other answers
Replace the bindings for the insert/delete events
Same as (2), but wrap it up in a separate widget.
(2) or (3) would be preferable, however, the solution isn't obvious. However, a worked solution is available on the unpythonic wiki:
from Tkinter import Text
from idlelib.WidgetRedirector import WidgetRedirector
class ReadOnlyText(Text):
def __init__(self, *args, **kwargs):
Text.__init__(self, *args, **kwargs)
self.redirector = WidgetRedirector(self)
self.insert = self.redirector.register("insert", lambda *args, **kw: "break")
self.delete = self.redirector.register("delete", lambda *args, **kw: "break")
If your use case is really simple, nbro's text.bind('<1>', lambda event: text.focus_set()) code solves the interactivity problem that Craig McQueen sees on OS X but that others don't see on Windows and Linux.
On the other hand, if your readonly data has any contextual structure, at some point you'll probably end up using Tkinter.Text.insert(position, text, taglist) to add it to your readonly Text box window under a tag. You'll do this because you want parts of the data to stand out based on context. Text that's been marked up with tags can be emphasized by calling .Text.tag_config() to change the font or colors, etc. Similarly, text that's been marked up with tags can have interactive bindings attached using .Text.tag_bind(). There's a good example of using these functions here. If a mark_for_paste() function is nice, a mark_for_paste() function that understands the context of your data is probably nicer.
This is how I did it. Making the state disabled at the end disallows the user to edit the text box but making the state normal before the text box is edited is necessary for text to be inserted.
from tkinter import *
text=Text(root)
text.pack()
text.config(state="normal")
text.insert(END, "Text goes here")
text.config(state="disabled")
from Tkinter import *
root = Tk()
text = Text(root)
text.insert(END,"Some Text")
text.configure(state='disabled')
Use this code in windows if you want to disable user edit and allow Ctrl+C for copy on screen text:
def txtEvent(event):
if(event.state==12 and event.keysym=='c' ):
return
else:
return "break"
txt.bind("<Key>", lambda e: txtEvent(e))
If selecting text is not something you need disabling the state is the simplest way to go. In order to support copying you can use an external entity - a Button - to do the job. Whenever the user presses the button the contents of Text will be copied to clipboard. Tk has an in-build support of handling the clipboard (see here) so emulating the behaviour of Ctrl-C is an easy task. If you are building let's say a console where log messages are written you can go further and add an Entry where the user can specify the number of log messages he wants to copy.
Many mentioned you can't copy from the text widget when the state is disabled. For me on Ubuntu Python 3.8.5 the copying issue turned out to be caused by the widget not having focus on Ubuntu (works on Windows).
I have been using the solution with setting the state to disabled and then switching the state, when I need to edit it programmatically using 1) text.config(state=tkinter.NORMAL) 2) editing the text and 3) text.config(state=tkinter.DISABLED).
On windows I was able to copy text from the widget normally, but on Ubuntu it would look like I had selected the text, but I wasn't able to copy it.
After some testing it turned out, that I could copy it as long as the text widget had focus. On Windows the text widget seems to get focus, when you click it regardless of the state, but on Ubuntu clicking the text widget doesn't focus it.
So I fixed this problem by binding the text.focus_set() to the mouse click event "<Button>":
import tkinter
root = tkinter.Tk()
text0 = tkinter.Text(root, state=tkinter.DISABLED)
text0.config(state=tkinter.NORMAL)
text0.insert(1.0, 'You can not copy or edit this text.')
text0.config(state=tkinter.DISABLED)
text0.pack()
text1 = tkinter.Text(root, state=tkinter.DISABLED)
text1.config(state=tkinter.NORMAL)
text1.insert(1.0, 'You can copy, but not edit this text.')
text1.config(state=tkinter.DISABLED)
text1.bind("<Button>", lambda event: text1.focus_set())
text1.pack()
For me at least, that turned out to be a simple but effective solution, hope someone else finds it useful.
Disabling the Text widget is not ideal, since you would then need to re-enable it in order to update it. An easier way is to catch the mouse button and any keystrokes. So:
textWidget.bind("<Button-1>", lambda e: "break")
textWidget.bind("<Key>", lambda e: "break")
seems to do the trick. This is how I disabled my "line numbers" Text widget in a text editor. The first line is the more powerful one. I'm not sure the second is needed, but it makes me feel better having it there. :)
This can also be done in Frames
from tkinter import *
root = Tk()
area = Frame(root)
T = (area, height=5, width=502)
T.pack()
T.insert(1.0, "lorem ipsum")
T.config(state=DISABLED)
area.pack()
root.mainloop()
You could use a Label instead. A Label can be edited programmatically and cannot be edited by the user.
I need a widget in TKinter to be a global widget, however, I need the text displayed in it to be different every time. I'm quite new with TKinter and haven't yet successfully managed to edit an option in a widget.
I assume it's something to do with widget.add_option() but the documentation is quite confusing to me and I can't figure out the command.
I specifically just need to edit the text = "" section.
Thanks
EDIT:
gm1_b_current_choice_label = Label(frame_gm1_b, text = "Current input is:\t %s"% str(save_game[6]))
I specifically need to update the save_game[6] (which is a list) in the widget creation, but I assume once the widget is created that's it. I could create the widget every time before I place it but this causes issues with destroying it later.
You can use the .config method to change options on a Tkinter widget.
To demonstrate, consider this simple script:
from Tkinter import Tk, Button, Label
root = Tk()
label = Label(text="This is some text")
label.grid()
def click():
label.config(text="This is different text")
Button(text="Change text", command=click).grid()
root.mainloop()
When the button is clicked, the label's text is changed.
Note that you could also do this:
label["text"] = "This is different text"
or this:
label.configure(text="This is different text")
All three solutions ultimately do the same thing, so you can pick whichever you like.
You can always use the .configure(text = "new text") method, as iCodez suggested.
Alternatively, try using a StringVar as the text_variable parameter:
my_text_var = StringVar(frame_gm1_b)
my_text_var.set("Current input is:\t %s"% str(save_game[6]))
gm1_b_current_choice_label = Label(frame_gm1_b, textvariable = my_text_var)
Then, you can change the text by directly altering my_text_var:
my_text_var.set("Some new text")
This can be linked to a button or another event-based widget, or however else you want to change the text.
I'm working on my first Python program and have little idea what I'm doing. I want to re-bind ctrl-a (control a) to select all text in a Text widget. The current binding is ctrl-/ (control /). The binding part jumps right to the function but the actual text selection doesn't work. Instead, the cursor jumps to the first character on the first line (like it should) and nothing else happens. I'm sure this is embaressingly easy to fix but after spending hour an hours on it, I can't figure out what's wrong.
Python 3, Windows:
from tkinter import *
# Select all the text in textbox (not working)
def select_all(event):
textbox.tag_add(SEL, "1.0", END)
textbox.mark_set(INSERT, "1.0")
textbox.see(INSERT)
# Open a window
mainwin = Tk()
# Create a text widget
textbox = Text(mainwin, width=40, height=10)
textbox.pack()
# Add some text
textbox.insert(INSERT, "Select some text then right click in this window")
# Add the binding
textbox.bind("<Control-Key-a>", select_all)
# Start the program
mainwin.mainloop()
So the new code is...
from tkinter import *
# Select all the text in textbox
def select_all(event):
textbox.tag_add(SEL, "1.0", END)
textbox.mark_set(INSERT, "1.0")
textbox.see(INSERT)
return 'break'
# Open a window
mainwin = Tk()
# Create a text widget
textbox = Text(mainwin, width=40, height=10)
textbox.pack()
# Add some text
textbox.insert(INSERT, "Select some text then right click in this window")
# Add the binding
textbox.bind("<Control-Key-a>", select_all)
textbox.bind("<Control-Key-A>", select_all) # just in case caps lock is on
# Start the program
mainwin.mainloop()
and yes it works flawlessly. Thank you, very much Bryan Oakley. Steven Rumbalski: that's a VERY good point, I've followed your advice as well.
You need to both do the selection and then inhibit the default action by having your function return the string "break".
This is due to how Tkinter processes events. It uses what it calls "bind tags". Even though it looks like you are binding to a widget, you are actually binding to a tag that is the name of the widget. There can also be bindings to the widget class, to the toplevel window that the widget is in, and the tag "all" (plus, you can invent your own tags if you wish).
The default ordering of these tags is from most-specific to least-specific, and events are processed in that order. Meaning, if you have a binding both on the widget (most specific) and the class (less specific), the binding will fire for the widget first, and then for the class binding (and then for the toplevel, and then for "all").
What this means is that by default, a binding on a widget augments rather than replaces a default binding. The good news is, you can inhibit any further bindings from firing by simply returning the string "break", which stops the chain of bindings from doing any more work.
You can do that with a module named pyautogui
Just run the command where you want to add the event,
import pyautogui
..., command=lambda *awargs:pyautogui.hotkey("ctrl","a")
Make sure you install the module. If you are on windows, install it by
pip install pyautogui
How would i go about locking a Text widget so that the user can only select and copy text out of it, but i would still be able to insert text into the Text from a function or similar?
Have you tried simply disabling the text widget?
text_widget.configure(state="disabled")
On some platforms, you also need to add a binding on <1> to give the focus to the widget, otherwise the highlighting for copy doesn't appear:
text_widget.bind("<1>", lambda event: text_widget.focus_set())
If you disable the widget, to insert programatically you simply need to
Change the state of the widget to NORMAL
Insert the text, and then
Change the state back to DISABLED
As long as you don't call update in the middle of that then there's no way for the user to be able to enter anything interactively.
Sorry I'm late to the party but I found this page looking for the same solution as you.
I found that if you "disable" the Text widget by default and then "normal" it at the beginning of a function that gives it input and "disable" it again at the end of the function.
def __init__():
self.output_box = Text(fourth_frame, width=160, height=25, background="black", foreground="white")
self.output_box.configure(state="disabled")
def somefunction():
self.output_box.configure(state="normal")
(some function goes here)
self.output_box.configure(state="disable")
I stumbled upon the state="normal"/state="disabled" solution as well, however then you are unable to select and copy text out of it. Finally I found the solution below from: Is there a way to make the Tkinter text widget read only?, and this solution allows you to select and copy text as well as follow hyperlinks.
import Tkinter
root = Tkinter.Tk()
readonly = Tkinter.Text(root)
readonly.bind("<Key>", lambda e: "break")