Can't get grid_remove() to work - python

In the app I'm working on I have a class setup to handle all my GUI. One method in this class creates a frame and populates a group of radiobutton's from a loop. This method will be called multiple times from outside the class to redraw this frame. The problem I have is that when the frame is redrawn it is actually just overwriting the existing frame (old frame persists). So if there are fewer options in a later call, the earlier options are still visible. I have tried doing a grid_remove on the frame first but can't get that to work. So my question is, why is the grid_remove() not working in the initMech() method below?
#!/usr/bin/env python
from Tkinter import *
class MWindow(Frame):
def __init__(self, parent) :
Frame.__init__(self, parent)
self.parent = parent
self.initUI()
def initUI(self):
topframe = Frame(self.parent, bd=2, relief=GROOVE, padx=5, pady=5, width=300, height=50)
topframe.grid(row=0, column=0)
desc = Button(topframe, text="list1", command=lambda:set_list(1))
desc.grid(row=0,column=1)
desc2 = Button(topframe, text="list2", command=lambda:set_list(2))
desc2.grid(row=0,column=2)
def initMech(self):
try:
radio_frame.grid_remove()
except:
print "can't remove"
radio_frame = Frame(self.parent, bd=2, relief=GROOVE, padx=5, pady=5, width=300, height=50)
radio_frame.grid(row=1, column=0)
variant=StringVar()
c = 0
for x in chas.v_list:
Radiobutton(radio_frame, text=x,variable=variant, value=x, command=lambda x = x:chas.set_vari(x)).grid(row=0, column=c)
c = c+1
def onExit(self):
self.parent.destroy()
class Mech():
def set_chass(self,chass):
try:
if self.chassis == chass:
pass
else:
self.chassis = chass
del self.vari
except AttributeError:
self.chassis = chass
def load_vari(self):
if self.chassis == 1:
self.v_list = ["a","b","c"]
else:
self.v_list = ["w", "x", "y", "z"]
win.initMech()
def set_vari(self, vari):
self.vari = vari
def set_list(num):
chas.set_chass(num)
chas.load_vari()
root = Tk()
win = MWindow(root)
chas = Mech()
root.mainloop()

It is not working because you're using a local variable named radio_frame, and that variable isn't defined yet. Most likely, the error message you are ignoring is telling you exactly that. Why are you trying to remove a frame that you haven't yet created?
Also, are you aware that grid_remove only removes the widget from view, it doesn't destroy it? Thus, if you call this function several times you'll have several invisible versions of this frame, all using up memory.

Related

how to print the contents of the Text widget in python [duplicate]

How to get Tkinter input from the Text widget?
EDIT
I asked this question to help others with the same problem - that is the reason why there is no example code. This issue had been troubling me for hours and I used this question to teach others. Please do not rate it as if it was a real question - the answer is the thing that matters.
To get Tkinter input from the text box, you must add a few more attributes to the normal .get() function. If we have a text box myText_Box, then this is the method for retrieving its input.
def retrieve_input():
input = self.myText_Box.get("1.0",END)
The first part, "1.0" means that the input should be read from line one, character zero (ie: the very first character). END is an imported constant which is set to the string "end". The END part means to read until the end of the text box is reached. The only issue with this is that it actually adds a newline to our input. So, in order to fix it we should change END to end-1c(Thanks Bryan Oakley) The -1c deletes 1 character, while -2c would mean delete two characters, and so on.
def retrieve_input():
input = self.myText_Box.get("1.0",'end-1c')
Here is how I did it with python 3.5.2:
from tkinter import *
root=Tk()
def retrieve_input():
inputValue=textBox.get("1.0","end-1c")
print(inputValue)
textBox=Text(root, height=2, width=10)
textBox.pack()
buttonCommit=Button(root, height=1, width=10, text="Commit",
command=lambda: retrieve_input())
#command=lambda: retrieve_input() >>> just means do this when i press the button
buttonCommit.pack()
mainloop()
with that, when i typed "blah blah" in the text widget and pressed the button, whatever i typed got printed out. So i think that is the answer for storing user input from Text widget to variable.
To get Tkinter input from the text box in python 3 the complete student level program used by me is as under:
#Imports all (*) classes,
#atributes, and methods of tkinter into the
#current workspace
from tkinter import *
#***********************************
#Creates an instance of the class tkinter.Tk.
#This creates what is called the "root" window. By conventon,
#the root window in Tkinter is usually called "root",
#but you are free to call it by any other name.
root = Tk()
root.title('how to get text from textbox')
#**********************************
mystring = StringVar()
####define the function that the signup button will do
def getvalue():
## print(mystring.get())
#*************************************
Label(root, text="Text to get").grid(row=0, sticky=W) #label
Entry(root, textvariable = mystring).grid(row=0, column=1, sticky=E) #entry textbox
WSignUp = Button(root, text="print text", command=getvalue).grid(row=3, column=0, sticky=W) #button
############################################
# executes the mainloop (that is, the event loop) method of the root
# object. The mainloop method is what keeps the root window visible.
# If you remove the line, the window created will disappear
# immediately as the script stops running. This will happen so fast
# that you will not even see the window appearing on your screen.
# Keeping the mainloop running also lets you keep the
# program running until you press the close buton
root.mainloop()
In order to obtain the string in a Text widget one can simply use get method defined for Text which accepts 1 to 2 arguments as start and end positions of characters, text_widget_object.get(start, end=None). If only start is passed and end isn't passed it returns only the single character positioned at start, if end is passed as well, it returns all characters in between positions start and end as string.
There are also special strings, that are variables to the underlying Tk. One of them would be "end" or tk.END which represents the variable position of the very last char in the Text widget. An example would be to returning all text in the widget, with text_widget_object.get('1.0', 'end') or text_widget_object.get('1.0', 'end-1c') if you don't want the last newline character.
Demo
See below demonstration that selects the characters in between the given positions with sliders:
try:
import tkinter as tk
except:
import Tkinter as tk
class Demo(tk.LabelFrame):
"""
A LabeFrame that in order to demonstrate the string returned by the
get method of Text widget, selects the characters in between the
given arguments that are set with Scales.
"""
def __init__(self, master, *args, **kwargs):
tk.LabelFrame.__init__(self, master, *args, **kwargs)
self.start_arg = ''
self.end_arg = None
self.position_frames = dict()
self._create_widgets()
self._layout()
self.update()
def _create_widgets(self):
self._is_two_args = tk.Checkbutton(self,
text="Use 2 positional arguments...")
self.position_frames['start'] = PositionFrame(self,
text="start='{}.{}'.format(line, column)")
self.position_frames['end'] = PositionFrame( self,
text="end='{}.{}'.format(line, column)")
self.text = TextWithStats(self, wrap='none')
self._widget_configs()
def _widget_configs(self):
self.text.update_callback = self.update
self._is_two_args.var = tk.BooleanVar(self, value=False)
self._is_two_args.config(variable=self._is_two_args.var,
onvalue=True, offvalue=False)
self._is_two_args['command'] = self._is_two_args_handle
for _key in self.position_frames:
self.position_frames[_key].line.slider['command'] = self.update
self.position_frames[_key].column.slider['command'] = self.update
def _layout(self):
self._is_two_args.grid(sticky='nsw', row=0, column=1)
self.position_frames['start'].grid(sticky='nsew', row=1, column=0)
#self.position_frames['end'].grid(sticky='nsew', row=1, column=1)
self.text.grid(sticky='nsew', row=2, column=0,
rowspan=2, columnspan=2)
_grid_size = self.grid_size()
for _col in range(_grid_size[0]):
self.grid_columnconfigure(_col, weight=1)
for _row in range(_grid_size[1] - 1):
self.grid_rowconfigure(_row + 1, weight=1)
def _is_two_args_handle(self):
self.update_arguments()
if self._is_two_args.var.get():
self.position_frames['end'].grid(sticky='nsew', row=1, column=1)
else:
self.position_frames['end'].grid_remove()
def update(self, event=None):
"""
Updates slider limits, argument values, labels representing the
get method call.
"""
self.update_sliders()
self.update_arguments()
def update_sliders(self):
"""
Updates slider limits based on what's written in the text and
which line is selected.
"""
self._update_line_sliders()
self._update_column_sliders()
def _update_line_sliders(self):
if self.text.lines_length:
for _key in self.position_frames:
self.position_frames[_key].line.slider['state'] = 'normal'
self.position_frames[_key].line.slider['from_'] = 1
_no_of_lines = self.text.line_count
self.position_frames[_key].line.slider['to'] = _no_of_lines
else:
for _key in self.position_frames:
self.position_frames[_key].line.slider['state'] = 'disabled'
def _update_column_sliders(self):
if self.text.lines_length:
for _key in self.position_frames:
self.position_frames[_key].column.slider['state'] = 'normal'
self.position_frames[_key].column.slider['from_'] = 0
_line_no = int(self.position_frames[_key].line.slider.get())-1
_max_line_len = self.text.lines_length[_line_no]
self.position_frames[_key].column.slider['to'] = _max_line_len
else:
for _key in self.position_frames:
self.position_frames[_key].column.slider['state'] = 'disabled'
def update_arguments(self):
"""
Updates the values representing the arguments passed to the get
method, based on whether or not the 2nd positional argument is
active and the slider positions.
"""
_start_line_no = self.position_frames['start'].line.slider.get()
_start_col_no = self.position_frames['start'].column.slider.get()
self.start_arg = "{}.{}".format(_start_line_no, _start_col_no)
if self._is_two_args.var.get():
_end_line_no = self.position_frames['end'].line.slider.get()
_end_col_no = self.position_frames['end'].column.slider.get()
self.end_arg = "{}.{}".format(_end_line_no, _end_col_no)
else:
self.end_arg = None
self._update_method_labels()
self._select()
def _update_method_labels(self):
if self.end_arg:
for _key in self.position_frames:
_string = "text.get('{}', '{}')".format(
self.start_arg, self.end_arg)
self.position_frames[_key].label['text'] = _string
else:
_string = "text.get('{}')".format(self.start_arg)
self.position_frames['start'].label['text'] = _string
def _select(self):
self.text.focus_set()
self.text.tag_remove('sel', '1.0', 'end')
self.text.tag_add('sel', self.start_arg, self.end_arg)
if self.end_arg:
self.text.mark_set('insert', self.end_arg)
else:
self.text.mark_set('insert', self.start_arg)
class TextWithStats(tk.Text):
"""
Text widget that stores stats of its content:
self.line_count: the total number of lines
self.lines_length: the total number of characters per line
self.update_callback: can be set as the reference to the callback
to be called with each update
"""
def __init__(self, master, update_callback=None, *args, **kwargs):
tk.Text.__init__(self, master, *args, **kwargs)
self._events = ('<KeyPress>',
'<KeyRelease>',
'<ButtonRelease-1>',
'<ButtonRelease-2>',
'<ButtonRelease-3>',
'<Delete>',
'<<Cut>>',
'<<Paste>>',
'<<Undo>>',
'<<Redo>>')
self.line_count = None
self.lines_length = list()
self.update_callback = update_callback
self.update_stats()
self.bind_events_on_widget_to_callback( self._events,
self,
self.update_stats)
#staticmethod
def bind_events_on_widget_to_callback(events, widget, callback):
"""
Bind events on widget to callback.
"""
for _event in events:
widget.bind(_event, callback)
def update_stats(self, event=None):
"""
Update self.line_count, self.lines_length stats and call
self.update_callback.
"""
_string = self.get('1.0', 'end-1c')
_string_lines = _string.splitlines()
self.line_count = len(_string_lines)
del self.lines_length[:]
for _line in _string_lines:
self.lines_length.append(len(_line))
if self.update_callback:
self.update_callback()
class PositionFrame(tk.LabelFrame):
"""
A LabelFrame that has two LabelFrames which has Scales.
"""
def __init__(self, master, *args, **kwargs):
tk.LabelFrame.__init__(self, master, *args, **kwargs)
self._create_widgets()
self._layout()
def _create_widgets(self):
self.line = SliderFrame(self, orient='vertical', text="line=")
self.column = SliderFrame(self, orient='horizontal', text="column=")
self.label = tk.Label(self, text="Label")
def _layout(self):
self.line.grid(sticky='ns', row=0, column=0, rowspan=2)
self.column.grid(sticky='ew', row=0, column=1, columnspan=2)
self.label.grid(sticky='nsew', row=1, column=1)
self.grid_rowconfigure(1, weight=1)
self.grid_columnconfigure(1, weight=1)
class SliderFrame(tk.LabelFrame):
"""
A LabelFrame that encapsulates a Scale.
"""
def __init__(self, master, orient, *args, **kwargs):
tk.LabelFrame.__init__(self, master, *args, **kwargs)
self.slider = tk.Scale(self, orient=orient)
self.slider.pack(fill='both', expand=True)
if __name__ == '__main__':
root = tk.Tk()
demo = Demo(root, text="text.get(start, end=None)")
with open(__file__) as f:
demo.text.insert('1.0', f.read())
demo.text.update_stats()
demo.pack(fill='both', expand=True)
root.mainloop()
I think this is a better way-
variable1=StringVar() # Value saved here
def search():
print(variable1.get())
return ''
ttk.Entry(mainframe, width=7, textvariable=variable1).grid(column=2, row=1)
ttk.Label(mainframe, text="label").grid(column=1, row=1)
ttk.Button(mainframe, text="Search", command=search).grid(column=2, row=13)
On pressing the button, the value in the text field would get printed.
But make sure You import the ttk separately.
The full code for a basic application is-
from tkinter import *
from tkinter import ttk
root=Tk()
mainframe = ttk.Frame(root, padding="10 10 12 12")
mainframe.grid(column=0, row=0, sticky=(N, W, E, S))
mainframe.columnconfigure(0, weight=1)
mainframe.rowconfigure(0, weight=1)
variable1=StringVar() # Value saved here
def search():
print(variable1.get())
return ''
ttk.Entry(mainframe, width=7, textvariable=variable1).grid(column=2, row=1)
ttk.Label(mainframe, text="label").grid(column=1, row=1)
ttk.Button(mainframe, text="Search", command=search).grid(column=2, row=13)
root.mainloop()
I faced the problem of gettng entire text from Text widget and following solution worked for me :
txt.get(1.0,END)
Where 1.0 means first line, zeroth character (ie before the first!)
is the starting position and END is the ending position.
Thanks to Alan Gauld in this link
I did come also in search of how to get input data from the Text widget. Regarding the problem with a new line on the end of the string. You can just use .strip() since it is a Text widget that is always a string.
Also, I'm sharing code where you can see how you can create multiply Text widgets and save them in the dictionary as form data, and then by clicking the submit button get that form data and do whatever you want with it. I hope it helps others. It should work in any 3.x python and probably will work in 2.7 also.
from tkinter import *
from functools import partial
class SimpleTkForm(object):
def __init__(self):
self.root = Tk()
def myform(self):
self.root.title('My form')
frame = Frame(self.root, pady=10)
form_data = dict()
form_fields = ['username', 'password', 'server name', 'database name']
cnt = 0
for form_field in form_fields:
Label(frame, text=form_field, anchor=NW).grid(row=cnt,column=1, pady=5, padx=(10, 1), sticky="W")
textbox = Text(frame, height=1, width=15)
form_data.update({form_field: textbox})
textbox.grid(row=cnt,column=2, pady=5, padx=(3,20))
cnt += 1
conn_test = partial(self.test_db_conn, form_data=form_data)
Button(frame, text='Submit', width=15, command=conn_test).grid(row=cnt,column=2, pady=5, padx=(3,20))
frame.pack()
self.root.mainloop()
def test_db_conn(self, form_data):
data = {k:v.get('1.0', END).strip() for k,v in form_data.items()}
# validate data or do anything you want with it
print(data)
if __name__ == '__main__':
api = SimpleTkForm()
api.myform()
I would argue that creating a simple extension of Text and turning text into a property is the cleanest way to go. You can then stick that extension in some file that you always import, and use it instead of the original Text widget. This way, instead of having to remember, write, repeat, etc all the hoops tkinter makes you jump through to do the simplest things, you have a butt-simple interface that can be reused in any project. You can do this for Entry, as well, but the syntax is slightly different.
import tkinter as tk
root = tk.Tk()
class Text(tk.Text):
#property
def text(self) -> str:
return self.get('1.0', 'end-1c')
#text.setter
def text(self, value) -> None:
self.replace('1.0', 'end-1c', value)
def __init__(self, master, **kwargs):
tk.Text.__init__(self, master, **kwargs)
#Entry version of the same concept as above
class Entry(tk.Entry):
#property
def text(self) -> str:
return self.get()
#text.setter
def text(self, value) -> None:
self.delete(0, 'end')
self.insert(0, value)
def __init__(self, master, **kwargs):
tk.Entry.__init__(self, master, **kwargs)
textbox = Text(root)
textbox.grid()
textbox.text = "this is text" #set
print(textbox.text) #get
entry = Entry(root)
entry.grid()
entry.text = 'this is text' #set
print(entry.text) #get
root.mainloop()
Lets say that you have a Text widget called my_text_widget.
To get input from the my_text_widget you can use the get function.
Let's assume that you have imported tkinter.
Lets define my_text_widget first, lets make it just a simple text widget.
my_text_widget = Text(self)
To get input from a text widget you need to use the get function, both, text and entry widgets have this.
input = my_text_widget.get()
The reason we save it to a variable is to use it in the further process, for example, testing for what's the input.

Tkinter is returning same value for every radio button?

I am popping up a custom dialog box using Tkinter.
I am opening it from another Tkinter window.
root = Tk()
class ListDialog:
def __init__(self, names, prompt):
self.names = names
self.sub_root = Tk()
self.sub_root.title("Intovex")
self.sub_root.iconbitmap("Icon.ico")
self.myfont = Font(root=self.sub_root, family="Arial", size=8)
self.sub_root.maxsize(320, 240)
self.sub_root.wm_attributes("-topmost", True)
self.sub_root.wm_attributes("-toolwindow", True)
self.var = IntVar()
label = Label(self.sub_root, text=prompt)
label.pack(fill=X)
c=1
print(names)
for i in names:
print(i)
r = Radiobutton(self.sub_root, text=i, variable=self.var, value=c, command=self.end)
r.pack(anchor=W)
c+=1
self.var.set(1)
button = Button(self.sub_root, command=self.endit, text="OK", bg = "#448DE0", fg="White", bd=0, width=12, pady=4, padx=4, height=1,font=self.myfont, highlightcolor="#A3C7F0")
button.pack(side=BOTTOM)
self.choice = names[0]
def end(self):
ch = self.var.get()
print(str(ch))
self.choice = self.names[ch - 1]
def endit(self):
self.sub_root.destroy()
def ask(self):
self.sub_root.mainloop()
var2 = StringVar()
def get_choice():
list = ListDialog(["Test1", "Test2"], "Testing")
list.ask()
var2.set(str(list.choice))
label = Label(root, text="", textvariable=var2)
button = Button(root, text="Test", command=get_choice)
label.pack()
button.pack()
root.mainloop()
However, it works when it is run alone by directly instantiating the class and invoking ask() method.
You may have seen that I have print statements everywhere in the code(it is for debugging) and I found where isn't it working
The print statement to print the names list parameter is printing the whole list correctly.
Inside the for-loop also it prints the elements in the names list correctly
When I click on a radio button it invokes the end() method. There it always prints the default value.
root = Tk()
class ListDialog:
def __init__(self, names, prompt):
self.names = names
self.sub_root = Tk()
self.sub_root.title("Intovex")
self.sub_root.iconbitmap("Icon.ico")
self.myfont = Font(root=self.sub_root, family="Arial", size=8)
self.sub_root.maxsize(320, 240)
self.sub_root.wm_attributes("-topmost", True)
self.sub_root.wm_attributes("-toolwindow", True)
self.var = IntVar()
label = Label(self.sub_root, text=prompt)
label.pack(fill=X)
c=1
print(names)
for i in names:
print(i)
r = Radiobutton(self.sub_root, text=i, variable=self.var, value=c, command=self.end)
r.pack(anchor=W)
c+=1
self.var.set(1)
button = Button(self.sub_root, command=self.endit, text="OK", bg = "#448DE0", fg="White", bd=0, width=12, pady=4, padx=4, height=1,font=self.myfont, highlightcolor="#A3C7F0")
button.pack(side=BOTTOM)
self.choice = names[0]
def end(self):
ch = self.var.get()
print(str(ch))
self.choice = self.names[ch - 1]
def endit(self):
self.sub_root.destroy()
def ask(self):
self.sub_root.mainloop()
list = ListDialog(["Test1", "Test2"], "Testing")
list.ask()
print(list.choice)
But it works if I open it as a TopLevel widget. But then the main window doesn't wait till the popup windows returns the value(choice).
The problem with the code in the first snippet is because you're calling Tk() more that once within the tkinter application — it confuses the interface code and can cause a variety of problems, as you're finding out.
If you replace the call inside the __init__() method of the ListDialog class, with one to tk.Toplevel() instead, then your code will start working.
I also streamlined the for loop that creates the Radiobuttons by changing it so to use the built-in enumerate() function to automatically keep a count of the names. In conjunction with that, I made the initial value of the IntVar zero which is not one of the values that selecting one the radiobuttons will assign it. This is so when the ListDialog is first displayed, none of them will be selected. It also ensures that the end() callback function will get called whenever the user presses one of them, so your app will always be informed when that happens.
Note that, although I didn't change it, you shouldn't name a variable list because that hides the name of the built-in class by that name. In general you should avoid naming anything something that conflicts with an existing standard Python name.
from tkinter import *
from tkinter.font import Font
root = Tk()
class ListDialog:
def __init__(self, names, prompt):
self.names = names
# self.sub_root = Tk() # Wrong - don't call Tk() more than once.
root.withdraw() # Hide root window.
self.sub_root = Toplevel() # Create another top-level window.
self.sub_root.title("Intovex")
# self.sub_root.iconbitmap("Icon.ico") # I don't have this file...
self.myfont = Font(root=self.sub_root, family="Arial", size=8)
self.sub_root.maxsize(320, 240)
self.sub_root.wm_attributes("-topmost", True)
self.sub_root.wm_attributes("-toolwindow", True)
self.var = IntVar(value=0) # Define and init value to one *not* produced by btns.
label = Label(self.sub_root, text=prompt)
label.pack(fill=X)
print(names)
for c, name in enumerate(names, start=1):
print(c)
r = Radiobutton(self.sub_root, text=c, variable=self.var, value=c,
command=self.end)
r.pack(anchor=W)
button = Button(self.sub_root, command=self.endit, text="OK", bg = "#448DE0",
fg="White", bd=0, width=12, pady=4, padx=4, height=1,
font=self.myfont, highlightcolor="#A3C7F0")
button.pack(side=BOTTOM)
self.choice = names[0]
def end(self):
ch = self.var.get()
print(str(ch))
self.choice = self.names[ch - 1]
def endit(self):
self.sub_root.destroy()
root.deiconify() # Reshow root window.
def ask(self):
self.sub_root.mainloop()
var2 = StringVar()
def get_choice():
list = ListDialog(["Test1", "Test2"], "Testing")
list.ask()
var2.set(str(list.choice))
label = Label(root, text="", textvariable=var2)
button = Button(root, text="Test", command=get_choice)
label.pack()
button.pack()
root.mainloop()

Tracing Entry that uses a StringVar has no effect on Label

Learning to use Tkinter and following an online tutorial. This is an example given where text is entered and then label will update accordingly to the input text field.
I'm trying it in Python3 on Mac and on Raspberry Pi and I don't see the effect of trace, hence the label doesn't get modified by the Entry. Any help would be appreciate (or any other simple example of how to use Entry and Trace together)
Thanks.
from tkinter import *
class HelloWorld:
def __init__(self, master):
frame = Frame(master)
frame.pack()
self.button = Button(
frame, text="Hello", command=self.button_pressed
)
self.button.pack(side=LEFT, padx=5)
self.label = Label(frame, text="This is a label")
self.label.pack()
a_var = StringVar()
a_var.trace("w", self.var_changed)
self.entry = Entry(frame,textvariable=a_var)
self.entry.pack()
def button_pressed(self):
self.label.config(text="I've been pressed!")
def var_changed(self, a, b, c):
self.label.config(text=self.entry.get())
def main():
root = Tk()
root.geometry("250x150+300+300")
ex = HelloWorld(root)
root.mainloop()
if __name__ == '__main__':
main()
The problem is that you are using a local variable for a_var, and on the Mac it is getting garbage-collected. Save a reference to the variable (eg: self.a_var rather than just a_var).
self.a_var = StringVar()
self.a_var.trace("w", self.var_changed)
self.entry = Entry(frame,textvariable=self.a_var)
self.entry.pack()
Note: if all you want is to keep a label and entry in sync, you don't need to use a trace. You can link them by giving them both the same textvariable:
self.entry = Entry(frame, textvariable=self.a_var)
self.label = Label(frame, textvariable=self.a_var)

IntVar().trace() not working

I'm just getting started coding in Python/Tkinter for a small Pymol plugin. Here I'm trying to have a toggle button and report its status when it is clicked. The button goes up and down, but toggleAVA never gets called. Any ideas why?
from Tkinter import *
import tkMessageBox
class AVAGnome:
def __init__(self, master):
# create frames
self.F1 = Frame(rootGnome, padx=5, pady=5, bg='red')
# checkbuttons
self.AVAselected = IntVar()
self.AVAselected.trace("w", self.toggleAVA)
self.AVAbutton = Checkbutton(self.F1, text='AVA', indicatoron=0, variable=self.AVAselected)
# start layout procedure
self.layout()
def layout(self):
self.F1.pack(side=TOP, fill=BOTH, anchor=NW)
#entry and buttons
self.AVAbutton.pack(side=LEFT)
def toggleAVA(self, *args):
if (self.AVAselected.get()):
avastatus = "selected"
else:
avastatus = "unselected"
tkMessageBox.showinfo("AVA status", avastatus)
def __init__(self):
open_GnomeUI()
def open_GnomeUI():
# initialize window
global rootGnome
rootGnome = Tk()
rootGnome.title('AVAGnome')
global gnomeUI
gnomeUI = AVAGnome(rootGnome)
I tested your code with Pymol.
Problem is because you use Tk() to create your window. You have to use Toplevel() and then it will work correctly with trace() or with command=.
Pymol is created with tkinter which can have only one window created with Tk() - it is main window in program. Every other window has to be created with Toplevel().
I have attached a working version of your code below. You can refer to it to learn where you went wrong. Generally, you have to mind how you structure your code if you are using a class format.This will help you visualize your code and debug better. You can read this discussion to help you.
from Tkinter import *
import tkMessageBox
class AVAGnome(Frame):
def __init__(self, parent):
Frame.__init__(self, parent)
# create frames
self.F1 = Frame(self, padx=5, pady=5, bg='red')
# checkbutton
self.AVAselected = IntVar()
self.AVAselected.trace("w", self.toggleAVA)
self.AVAbutton = Checkbutton(
self.F1, text='AVA', indicatoron=0, width=10,
variable=self.AVAselected)
# start layout procedure
self.F1.pack(side=TOP, fill=BOTH, anchor=NW)
self.AVAbutton.pack(side=LEFT) #entry and buttons
def toggleAVA(self, *args):
if (self.AVAselected.get()):
avastatus = "selected"
else:
avastatus = "unselected"
tkMessageBox.showinfo("AVA status", avastatus)
if __name__ == '__main__':
rootGnome = Tk()
rootGnome.title('AVAGnome')
gnomeUI = AVAGnome(rootGnome)
gnomeUI.pack(fill="both", expand=True)
gnomeUI.mainloop()
Update: The above code structure is for standalone tkinter programme. I am attempting to convert this working code to follow Pymol plugin example. Revised code is posted below and is susceptible to further revision.
# https://pymolwiki.org/index.php/Plugins_Tutorial
# I adapted from the example in the above link and converted my previous code to
#
from Tkinter import *
import tkMessageBox
def __init__(self): # The example had a self term here.
self.open_GnomeUI()
class AVAGnome(Frame):
def __init__(self, parent):
Frame.__init__(self, parent)
# create frames
self.F1 = Frame(self, padx=5, pady=5, bg='red')
# checkbutton
self.AVAselected = IntVar()
self.AVAselected.trace("w", self.toggleAVA)
self.AVAbutton = Checkbutton(
self.F1, text='AVA', indicatoron=0, width=10,
variable=self.AVAselected)
# start layout procedure
self.F1.pack(side=TOP, fill=BOTH, anchor=NW)
self.AVAbutton.pack(side=LEFT) #entry and buttons
def toggleAVA(self, *args):
if (self.AVAselected.get()):
avastatus = "selected"
else:
avastatus = "unselected"
tkMessageBox.showinfo("AVA status", avastatus)
# Note, I added a "self" term throughout function.
# Try w/ & w/o "self" to see which works.
def open_GnomeUI(self):
self.rootGnome = Tk()
self.rootGnome.title('AVAGnome')
self.gnomeUI = AVAGnome(self.rootGnome)
self.gnomeUI.pack(fill="both", expand=True)
self.gnomeUI.mainloop()

Updating a python Tkinter frame

I am having difficulty updating a python Tkinter frame. I draw the frame with
some labels and text fields, when a person presses a button, I want to do some
calculations and update the labels and text fields. I can print the data to my
stdout, but I cannot get the Tk screen to update. How can I get the countFld to display an updated value?
class Application(Frame):
def __init__(self):
self.root = Tk()
Frame.__init__(self, self.root)
self.count = 0
self.createWidgets()
def createWidgets(self):
self.countFrame = Frame(self, bd=2, relief=RIDGE)
Label(self.countFrame, text='Count:').pack(side=LEFT, padx=5)
self.countFld = IntVar()
Label(self.countFrame, text=str(self.count)).pack(side=RIGHT, padx=5)
self.countFld.set(self.count)
self.countFrame.pack(expand=1, fill=X, pady=10, padx=5)
self.CNTBTN = Button(self)
self.CNTBTN["text"] = "UPDATE"
self.CNTBTN["fg"] = "red"
self.CNTBTN["command"] = self.update_count
self.CNTBTN.pack({"side": "left"})
def update_count(self):
self.count = self.count + 1
print "Count = %" % self.count #prints correct value
self.countFld.set(self.count) #Does not update display
Your problem is that you do not attach the Variable to the widget. In addition you need to use a StringVar, as the Label Widget operates on Strings and not Ints.
Try something like:
self.countStr = StringVar()
self.countStr.set(str(self.count))
Label(self.countFrame, textvariable=self.countStr).pack(side=RIGHT, padx=5)
Tk updates the display when the eventloop is idle. So you need to re-enter the event loop after you set the new value.
You should try destroying the label itself and making it again in the code with the updated text and use self.root.update()

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