Develop Reference

Adding and updating new widget in tkinter in runtime

I am trying to build a GUI creator using Python and Tkinter, but ran into a problem.
My problem is How to add\update widgets in runtime?
for example:
I have created the main window.
In that main window, I have created a frame name w_frame which contains a bunch of widget.
Based on my input in the Text or Entry widget beside the w_frame, I want to update a particular widget.
Lets say w_frame contains a Entry widget, radio button, button and label all available with the basic or main attributes need to display it.
Now I want to change the background color of label.
In short I want to write the code label_name.property_name=value or for example a_label.bg=red in the text widget and as soon as I press apply button, the widget should change.
I have searched on web, but not able to find the required solution. Also tried using How can i update a certain widget in tkinter, but that does not work depending on my input.
from tkinter import *
root=Tk()
w_frame=Frame()
w_frame.pack()
def update_Frame():
a=u_text_wid.get("1.0",END)
b.config(a)
root.update()
def add_wid_in_frame():
global a,b
a=Button(w_frame,text='heelo')
a.pack()
b=Label(w_frame,text='heelo')
b.pack()
u_text_wid=Text()
u_text_wid.pack()
button1=Button(text="add",command=add_wid_in_frame)
button1.pack()
button1=Button(text="update",command=update_Frame)
button1.pack()
root.mainloop()
this results me in an error
unknown option "-bg="red"
Note:
I want to update the widget based on the property value provided by the user, so it wont be hard-code into the script.

You are getting the error because every thing you retrieve from Text widget is a string and you cannot directly pass an string to .config method, you need a keyword and then you can assign value which can be string.
According to your question and the comments on the question, what i have figured out is:
You want to run lable.config(bg='red') from the Text widget.
You want to change the property of specific widget.
Here's what you can do:
To run Tkinter code form Text widget, you can use:
getattr method
eval method
Just to change property of widget:
def update_Frame():
global bcd
a = u_text_wid.get("1.0", "end-1c")
b=a.split(",")
c=[tuple(i.split("=")) if "=" in i else i for i in b]
d=dict(i for i in c)
for key,value in d.items():
bcd[key]=value
We can use string to change property only in this format widget_name[key]=value.
Some Useful Links:
Eval()
Getattr()

For your case, you can use ast.literal_eval() to convert a JSON string to dictionary and use the dictionary in .config():
from ast import literal_eval
...
def update_Frame():
a = u_text_wid.get("1.0", "end-1c") # don't include ending newline
cnf = literal_eval(a) # convert JSON string to dictionary
b.config(cnf)
Example input of the JSON string:
{"fg":"yellow", "bg":"red"}
Note that you can also use json module to convert the JSON string as well.

How can I make a tkinter text widget unselectable?

I want to make my tkinter Text to be only an output and not an input. Through some research I've found that text.config(state="disabled") disables user input, but it still allows for selecting text, which I do not want.
How can I get my Text widget to be unselectable and unwritable?

The simplest way is to replace the default text bindings that support selection so that they do nothing. There are a couple ways to do this: using binding tags you can remove all default bindings, or you can remove the bindings to only a subset of default bindings.
Removing all default bindings
All bindings on widgets -- including the default bindings -- are associated with binding tags (also called "bindtags"). The binding tag for the the text widget is "Text", and all default bindings for the text widget are associated with this tag. If you remove that binding tag, you remove all Text-specific bindings.
The default binding tags for any widget is a tuple of the string representation of the widget, the internal widget class (in this case, "Text"), the internal name of the toplevel window (in this case, root), and the special tag "all".
In the following example we change the binding tags so that "Text" is not included, effectively removing all default bindings on the text widget:
import tkinter as tk
root = tk.Tk()
text = tk.Text(root)
text.bindtags((str(text), str(root), "all"))
Removing specific bindings
If you prefer to keep some of the default bindings, you can replace just the ones that you don't want. You do that by creating your own bindings, and having those bindings return the string "break". This special return value tells tkinter to stop processing the event any further.
For example, to prevent a double-click from selecting the word under the cursor you could do this:
text.bind("<Double-1>", lambda event: "break")
The downside to this approach is that you have to figure out what all of the bindings are that are related to the selection mechanism. On the other hand, it gives you complete control over what each key or button press does.

A read-only, unselectable text widget.
class Textarea(tkinter.Text):
def __init__(self, master, **kw):
super().__init__(master, **kw)
# disable text alteration
self.configure(state="disabled")
# untag any selection from beginning to end
def unselect(event):
self.tag_remove("sel", "1.0", "end")
# catch different ways selections could be made and unselect before copying or cutting
good = ["<ButtonRelease-1>", "<Leave>", "<Control-c>", "<Control-C>", "<Control-x>", "<Control-X>"]
better = good + ["<Shift-Left>", "<Shift-Up>", "<Shift-Right>", "<Shift-Down>", "<Shift-Home>", "<Shift-End>", "<Shift-Next>", "<Shift-Prior>"]
excessive = better + ["<Shift-KP_1>", "<Shift-KP_2>", "<Shift-KP_3>", "<Shift-KP_4>", "<Shift-KP_6>", "<Shift-KP_7>", "<Shift-KP_8>", "<Shift-KP_9>"]
for sequence in better:
self.bind(sequence, unselect, add="+")
# remove the appearance of selection
self.configure(selectforeground=self.cget("foreground"), selectbackground=self.cget("background"))
# disallow export of selection in case anything gets through
self.configure(exportselection=False)
Tested on python 3.8.2

I believe you will have to replace it with another widget that such as a Label or LabelFrame to accomplish this. As well you could use a from tkinter import messagebox and have the text you want pop up in another window (like an info window or error message window). I think that as far as the Text widget goes, setting the state to disabled is the best you can do for your purposes unfortunately and users will be able to copy that text despite being unable to edit it.

Here is the simplest method to prevent text from being selected/highlighted when you just want the Text widget to be an ordinary log that is disabled and unselectable.
When I had the issue I figured I just needed to set some Text configuration property (highlightbackground, highlightcolor or selectbackground) to "Black". Nothing worked. The Text widget employs tags that can be used to mark up the Text within the control. Configuration for user defined tags as well as the special tag "sel" have a number of settings including foreground (color) and background (color).
tag_config("sel", background="black")
Too easy right? That doesn't work either.
Turns out that the highlight is actually a bitmap overlaid on the text. This is controlled by the bgstipple (bitmap) configuration for the tag. The documentation indicates that there are a number of system bitmaps (shades of grey) that can be used however it is also possible to specify your own. The bitmap needs to be an xbm and it's easy to create your own as it's a text file.
Put the following in a file named transparent.xbm.
#define trans_width 2
#define trans_height 2
static unsigned char trans_bits[] = {
0x00, 0x00
};
Here it is...
class TextLog(tk.Text):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.tag_config("sel", bgstipple="#transparent.xbm",
foreground="white")
self.config(state="disabled")
def write_log(self, text="", clear=False)
self.configure(state='normal')
if clear is True:
self.delete("1.0","end")
self.insert(tk.END, text)
self.see(tk.END)
self.config(state="disabled")
Depending on where the .xbm is relative to the module using the TextLog you may need to prefix it with a path "#path/to/transparent.xbm"

How can I make this Tkinter text widget read only? [duplicate]

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.

Validation on Tkinter.Text widget?

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()

Hyperlink in Tkinter Text widget?

I am re designing a portion of my current software project, and want to use hyperlinks instead of Buttons. I really didn't want to use a Text widget, but that is all I could find when I googled the subject. Anyway, I found an example of this, but keep getting this error:
TclError: bitmap "blue" not defined
When I add this line of code (using the IDLE)
hyperlink = tkHyperlinkManager.HyperlinkManager(text)
The code for the module is located here and the code for the script is located here
Anyone have any ideas?
The part that is giving problems says foreground="blue", which is known as a color in Tkinter, isn't it?

If you don't want to use a text widget, you don't need to. An alternative is to use a label and bind mouse clicks to it. Even though it's a label it still responds to events.
For example:
import tkinter as tk
class App:
def __init__(self, root):
self.root = root
for text in ("link1", "link2", "link3"):
link = tk.Label(text=text, foreground="#0000ff")
link.bind("<1>", lambda event, text=text: self.click_link(event, text))
link.pack()
def click_link(self, event, text):
print("You clicked '%s'" % text)
root = tk.Tk()
app = App(root)
root.mainloop()
If you want, you can get fancy and add additional bindings for <Enter> and <Leave> events so you can alter the look when the user hovers. And, of course, you can change the font so that the text is underlined if you so choose.
Tk is a wonderful toolkit that gives you the building blocks to do just about whatever you want. You just need to look at the widgets not as a set of pre-made walls and doors but more like a pile of lumbar, bricks and mortar.

"blue" should indeed be acceptable (since you're on Windows, Tkinter should use its built-in color names table -- it might be a system misconfiguration on X11, but not on Windows); therefore, this is a puzzling problem (maybe a Tkinter misconfig...?). What happen if you use foreground="#00F" instead, for example? This doesn't explain the problem but might let you work around it, at least...