I'm having a rough time trying to create threads inside a tkinter GUI. To give some background on what I would like the code to do. This is a GUI that when the log buttons are pressed (e.g. log_1). I'd like to send a continuous command to fire a laser and eventually (after I tackle the current problem) log the subsequent parameters.
However, my issue is that I have 5 lasers needing to be fired at the same time (or very close to) and the more lasers I have in the logging state ON the more the time delay between the lasers firing. I guess this is an issue because my: fire_all() function in conjunction with the window after(100, fire_all) is not a threaded process so having more lasers firing results in more of a time delay between the onset of the command to fire.
My code is below. Does anyone have any suggestions how to implement this properly?
# start the GUI
import tkinter as tk
window = tk.Tk()
def fire_astrum(dev): # N = 100 # no of points in stream array, pulse_count = int(1) # no of desired pulses in pulse train #command is command volatge
#dev,ana_out,ana_in,N,pulse_count,pulse_on,pulse_off,command
#dev = 'Dev1'
ana_out = 'ao0'
ana_in = "ai0:1"# for non consecutive channels use: "Dev0/ai0:Dev0/ai4"
N = 100
pulse_count = 10
pulse_on = 45
pulse_off = 15
command = 3.5
channel = dev +'/' + ana_out
tot = dev + "/" + ana_in
duty = pulse_on/(pulse_on+pulse_off) # duty cycle in %
array_on = int(N*duty) # on values in array
array_off = int(N-array_on) # off values in array
samples = np.append(command*np.ones(array_on),np.zeros(array_off)) # command is command voltage (IPROG), sets up stream array to send to NI box
curr = np.empty((2,pulse_count*len(samples))) # Empty arrays for IMON,VMON
error = np.uint32(np.empty((3,pulse_count*len(samples)))) # # Empty arrays for Digital inputs with pull-up resistors (READY, ERR1 & ERR2)
#sample_clock = '/'+dev+'/ai/SampleClock'
arm_laser(dev,'on') # Sends 5V to Astrum to arm laser diode
time.sleep(0.3) # wait for 300ms before data stream
with nidaqmx.Task() as writeTask, nidaqmx.Task() as readcurr, nidaqmx.Task(): # as digitalread:#, nidaqmx.Task() as readvolt:
writeTask.ao_channels.add_ao_voltage_chan(channel,units = Volts)
writeTask.ao_channels.all.ao_max = 4 # Hard clamp Limit to 4V to protect laser diode
writeTask.ao_channels.all.ao_min = 0 # Set baseline to 0V (ground loop protection)
readcurr.ai_channels.add_ai_voltage_chan(tot, units = Volts,terminal_config = TerminalConfiguration.RSE) # define differntial NRE connfig of channels
#print(read_curr.ai_term_cfg)
#digitalread.di_channels.add_di_chan(dev + '/port0/line0:2',line_grouping=LineGrouping.CHAN_PER_LINE)
#writeTask.triggers.start_trigger.cfg_dig_edge_start_trig('/' + dev +'/' + terminal) #Setting the trigger on the analog input
writeTask.timing.cfg_samp_clk_timing(rate=(array_on/N)*1/pulse_on*1000*N,sample_mode= nidaqmx.constants.AcquisitionType.FINITE , samps_per_chan= pulse_count*len(samples))
readcurr.timing.cfg_samp_clk_timing(rate=(array_on/N)*1/pulse_on*1000*N, sample_mode= nidaqmx.constants.AcquisitionType.FINITE , samps_per_chan= pulse_count*len(samples))
#digitalread.timing.cfg_samp_clk_timing(rate=(array_on/N)*1/pulse_on*1000*N, sample_mode= nidaqmx.constants.AcquisitionType.FINITE , samps_per_chan= pulse_count*len(samples))
reader_curr = AnalogMultiChannelReader(readcurr.in_stream)
#digital = DigitalMultiChannelReader(digitalread.in_stream)
writer = AnalogSingleChannelWriter(writeTask.out_stream, auto_start=True)
writer.write_many_sample(samples)
time_vec = np.linspace(0, (pulse_on+pulse_off)*pulse_count, num=len(curr[0]), endpoint=True)
reader_curr.read_many_sample(data = curr,number_of_samples_per_channel = pulse_count*len(samples), timeout = nidaqmx.constants.WAIT_INFINITELY)# read from DAQ
#digital.read_many_sample_port_uint32(data = error,number_of_samples_per_channel = pulse_count*len(samples), timeout = nidaqmx.constants.WAIT_INFINITELY)# read from DAQ
curr = np.around(curr, 6) # Round all values to 6 decimals to avoid overflow
error = np.around(error, 6) # Round all values to 6 decimals to avoid overflow
print("The channels linked to WriteTask are: ")
for i in writeTask.ao_channels:
print(i)
print("The channels linked to ReadTask are: ")
for j in readcurr.ai_channels:
print(j)
################# Astrum parameters #########################
imon = curr[0]
vmon = curr[1]
ready = error[0]
err1 = error[1]
err2 = error[2]
trigger = np.tile(samples,pulse_count)
###############################################################
arm_laser(dev,'off')
###############################################################
V = np.max(vmon)
I = np.max(imon)
#for j in range(9):
laser_1[6].config(text = V)
laser_1[7].config(text = I)
def log1():
if log_1.config('text')[-1] =='ON':
log_1.config(text='OFF', bg="red",activebackground="red",textvariable=0)
print(log_1.config('textvariable')[-1])
else:
log_1.config(text='ON', bg="green",activebackground="green",textvariable=1)
print(log_1.config('textvariable')[-1])
def log2():
if log_2.config('text')[-1] =='ON':
log_2.config(text='OFF', bg="red",activebackground="red",textvariable=0)
print(log_2.config('textvariable')[-1])
else:
log_2.config(text='ON', bg="green",activebackground="green",textvariable=1)
print(log_2.config('textvariable')[-1])
def log3():
if log_3.config('text')[-1] =='ON':
log_3.config(text='OFF', bg="red",activebackground="red",textvariable=0)
print(log_3.config('textvariable')[-1])
else:
log_3.config(text='ON', bg="green",activebackground="green",textvariable=1)
print(log_3.config('textvariable')[-1])
def log4():
if log_4.config('text')[-1] =='ON':
log_4.config(text='OFF', bg="red",activebackground="red",textvariable=0)
print(log_4.config('textvariable')[-1])
else:
log_4.config(text='ON', bg="green",activebackground="green",textvariable=1)
print(log_4.config('textvariable')[-1])
def log5():
if log_5.config('text')[-1] =='ON':
log_5.config(text='OFF', bg="red",activebackground="red",textvariable=0)
print(log_5.config('textvariable')[-1])
else:
log_5.config(text='ON', bg="green",activebackground="green",textvariable=1)
print(log_5.config('textvariable')[-1])
##### logging button lasers ###########
log_1 = tk.Button(top_frame, width=8 , bd=4, text = 'OFF', command = log1, bg = "red")
log_1.grid(row = 2, column = 8)
log_2 = tk.Button(top_frame, width=8 , bd=4, text = 'OFF', command = log2, bg = "red") #, onvalue=1, offvalue=0)
log_2.grid(row = 3, column = 8)
log_3 = tk.Button(top_frame, width=8 , bd=4, text = 'OFF', command = log3, bg = "red") #, onvalue=1, offvalue=0)
log_3.grid(row = 4, column = 8)
log_4 = tk.Button(top_frame, width=8 , bd=4, text = 'OFF', command = log4, bg = "red") #, onvalue=1, offvalue=0)
log_4.grid(row = 5, column = 8)
log_5 = tk.Button(top_frame, width=8 , bd=4, text = 'OFF', command = log5, bg = "red") #, onvalue=1, offvalue=0)
log_5.grid(row = 6, column = 8)
def fire_all():
#global a
a = str(log_1.config('textvariable')[-1])
b = str(log_2.config('textvariable')[-1])
c = str(log_3.config('textvariable')[-1])
d = str(log_4.config('textvariable')[-1])
e = str(log_5.config('textvariable')[-1])
if a == '1':
fire_astrum('Dev1')
if b == '1':
fire_astrum('Dev2')
if c == '1':
fire_astrum('Dev3')
if d == '1':
fire_astrum('Dev4')
if e == '1':
fire_astrum('Dev5')
# call this function again in 100 milliseconds
window.after(100, fire_all)
window.after(100, fire_all)
window.mainloop()
you can probably launch fire_astrum in a thread from fire_all.
maybe like this:
import threading
...
if a == '1':
threading.Thread(target=lambda dev='Dev1': fire_astrum(dev)).start()
...
It is unclear how long fire_astrum takes to complete; it also sleeps for 300ms; there is no telling the outcome when fired every 100ms, you'll have to try.
I have written this code and for some reason it refuses to return any sort of value or input for slef.REV when used in the function post(self) however it will return a value when I try and return a value in the getlen() function which is used to reurn the number of characters in the review.I dont have this problem for any other variables that I retrieve data from within this class. Below is the relevant code, any help would be appreciated. the lines where this problem occures is the first functio calld post(lines 1-5) and 4 lines up from the bottom
def post(self):
MovieID = self.MovID
REV = self.REV
AddReview(conn,cursor,Add_Review,MovieID,REV)
print(REV)
def shrek_film(self):
self.title = "Shrek"
self.MovID = 1
self.root4 = tk.Toplevel()
self.root4.title("Watch Shreck")
self.root4.geometry("1400x800")
frame_4 = tk.Frame(self.root4, bg = "black")
frame_4.pack(fill = tk.BOTH, expand = True, padx=0 , pady=0)
frame_4.grid_columnconfigure(1,weight=1)
self.Create_canvas = tk.Canvas(frame_4, width=2000, height=1080)
self.Create_canvas.place(x=-50, y=-50)
self.Create_img = PhotoImage(file="shrek-landscape.gif")
self.Create_canvas.create_image(20, 20, anchor = NW, image=self.Create_img)
play_button= tk.Button(frame_4,bg="orange",text="play", command = self.addHistory)
play_button.place(x=700,y=400)
play_button.config(font=("Ariel","30"))
def gtelen():
Review = reviewbox.get('1.0',END)
REVLEN = len(Review)
REVLENLEFT = (231-len(Review))
if REVLEN >=230:
lenbox = tk.Label(frame_4 ,text="No words left",bg="orange")
lenbox.place(x=360,y=460)
lenbox.config(font=("Ariel","15"))
else:
lenbox = tk.Label(frame_4 ,text=REVLENLEFT,bg="orange")
lenbox.place(x=360,y=460)
lenbox.config(font=("Ariel","15"))
print(Review)
Words_button = tk.Button(frame_4, bg="orange",text="check number of words remaining", command=gtelen)
Words_button.place(x=150,y=460)
Words_button.config(font=("Ariel","10"))
reviewlable=tk.Label(frame_4,text="Write a review",bg="orange")
reviewlable.place(x=10,y=460)
reviewlable.config(font=("ariel","15"))
Review_button= tk.Button(frame_4,bg="orange",text="See Reviews")#, command = self.ViewReviews)
Review_button.place(x=490,y=450)
Review_button.config(font=("Ariel","15"))
reviewbox= Text(frame_4,width=100,height=12)
reviewbox.place(x=10,y=500)
self.REV = reviewbox.get('1.0',END)
post_button = tk.Button(frame_4,bg="orange",text="Post Review", command = self.post)
post_button.place(x=830,y=650)
post_button.config(font=("Ariel","15"))
You can use Entry instead and use a StringVar
v = StringVar() # Create StringVar
reviewbox = Entry(frame_4, width = 100, height = 12, textvariable = v) # Create Entry widget
reviewbox.place(x = 10, y = 500) # Place Entry widget
self.REV = v.get() # Get contents of StringVar
The line self.REV = reviewbox.get('1.0',END) is being called about a millisecond after creating the text widget. The user will not even have seen the widget yet, much less have had time to type in it.
You can't call the get() method until after the user has had a chance to enter data, such as inside the post method.
def post(self):
MovieID = self.MovID
REV = reviewbox.get("1.0", "end")
AddReview(conn,cursor,Add_Review,MovieID,REV)
print(REV)
I want to validate two tkinter entries. One called minimum and the other called maximum. Of course, I want to make sure that minimum does not exceed maximum. And there is a third entry called increment which has to be lesser than maximum. There are a set of 15 such entries which I am trying to validate.
I have tried using for loop and tracing the textvariable of each entry. But inside the for loop, I am able to validate only a single entry box. Also, when I skip the validation for that specific one entry called the txtCab, it throws the following exception: If I do it for all the widgets, it does work, but fails some times.
Exception in Tkinter callback
Traceback (most recent call last):
File "C:\Users\beejb\AppData\Local\Programs\Python\Python37-32\lib\tkinter\__init__.py", line 1705, in __call__
return self.func(*args)
File "C:\PROSAIL_5B_Fortran\PROSAIL_5B_FORTRAN\PROSAIL.py", line 191, in min_max
minVar = eval("self.txtVar_"+ str(wid)+ "_min.get()")
File "<string>", line 1, in <module>
NameError: name 'self' is not defined
The validation function I have used is:
def min_max(*args):
alltextFields = ["N","Cab","Car","Cw","Cm","Cbrown", "rsoil0","LIDFa","LIDFb","TypeLIDF","LAI","hspot","tts","tto","psi" ]
for wid in alltextFields:
if eval("self." + wid + "_variable.get()"):
minVar = eval("self.txtVar_"+ str(wid)+ "_min.get()")
maxVar = eval("self.txtVar_"+ str(wid) + "_max.get()")
rangeVar = eval("self.txtVar_"+ str(wid) + "_range.get()")
##
## print((minVar))
## print((maxVar))
## print((rangeVar))
if len(minVar) > 0 and len(maxVar):
if (minVar) > (maxVar):
messagebox.showinfo("Input Error", "Minimum should not be greater than maximum")
if len(rangeVar) > 0 and len(maxVar) > 0:
if (rangeVar) > (maxVar) :
messagebox.showinfo("Input Error", "Increment cannot exceed maximum limit")
## print(self.txtVar_Cab_min.get()); print(self.txtVar_Cab_max.get());
## print(self.txtVar_N_min.get()); print(self.txtVar_N_max.get());
if len(self.txtVar_Cab_min.get()) > 0 and len(self.txtVar_Cab_max.get()) > 0 and len(self.txtVar_Cab_range.get()) > 0:
if (self.txtVar_Cab_min.get()) > (self.txtVar_Cab_max.get()):
messagebox.showinfo("Input Data Error", "Minimum should not be greater than maximum!!")
if (self.txtVar_Cab_range.get()) > (self.txtVar_Cab_max.get()):
messagebox.showinfo("Error", "Increment cannot exceed maximum!!")
Another validation function I have tried is:
def validateMRM(self,value, text,W):
vMin,vMax,vRange;
entry = self.controller.nametowidget(W)
print(entry)
if entry == self.txt_N_min:
print(entry.get())
print(self.txtVar_N_max.get())
print(self.txtVar_N_range.get())
alltextFields = ["txt_N","txt_Cab","txt_Car","txt_Cab","txt_Cw","txt_Cw","txt_Cm","txt_Cbrown","txt_Cm", "txt_rsoil0",
"txt_LIDFa","txt_LIDFb","txt_TypeLIDF","txt_LAI","txt_hspot","txt_hspot","txt_tts","txt_tto","txt_psi"
]
for wid in alltextFields:
typeOfVar = wid.split("_")
if entry == eval("self.txt_" + str(typeOfVar[1])+ "_min"):
vMin = eval("self.txtVar_" + str(typeOfVar[1])+ "_min.get()")
print(eval("self.txtVar_" + str(typeOfVar[1])+ "_min.get()"))
vMax = eval("self.txtVar_" + str(typeOfVar[1])+ "_max.get()")
print(eval("self.txtVar_" + str(typeOfVar[1])+ "_max.get()"))
vRange = eval("self.txtVar_" + str(typeOfVar[1])+ "_range.get()")
print(eval("self.txtVar_" + str(typeOfVar[1])+ "_range.get()"))
print(vMin); print(vMax); print(vRange)
if len(vMin) > 0 and len(vMax) > 0 and len(vRange) > 0:
if (vMin) > (vMax):
messagebox.showinfo("Error", "Minimum cannot be greater than maximum")
if (vRange) > (vMax) :
messagebox.showinfo("Error", "Increment cannot exceed the maximum limit")
print(len(entry.get()))
if len(entry.get())>2:
And here is how all the entries are created:
self.lbl_N = tk.Label(self,text="Structure Coefficient(N)",anchor="w",width=40,bg='white'); self.lbl_N.grid(row=3,column=4,padx=4,pady=4);
self.N_variable = tk.BooleanVar()
self.chk_N = tk.Checkbutton(self,variable=self.N_variable, command=lambda:self.show_hide()); self.chk_N.grid(row=3,column=6,padx=4,pady=4);
self.txt_N = tk.Entry(self,width=10,validate = 'key', validatecommand = vcmd); self.txt_N.grid(row=3,column=7,padx=4,pady=4);
self.txtVar_N_min = tk.StringVar(); self.txtVar_N_max = tk.StringVar(); self.txtVar_N_range = tk.StringVar();
self.txtVar_N_min.trace("w", min_max); self.txtVar_N_max.trace("w", min_max); self.txtVar_N_range.trace("w", min_max);
self.txt_N_min = tk.Entry(self,width=5,validate = 'key',textvariable=self.txtVar_N_min, validatecommand = vcmd_min_max);
self.txt_N_max = tk.Entry(self,width=5,validate = 'key', textvariable=self.txtVar_N_max,validatecommand = vcmd_min_max);
self.txt_N_range = tk.Entry(self,width=5,validate = 'key', textvariable=self.txtVar_N_range,validatecommand = vcmd_min_max);
There are a set of fourteen such entries and I need to validate each of them.
But none of this gives the actual output I want. It works some time and fails some other times.
I am not sure why is that happening and I have spent a hell of time with this validation.
I'm not sure whether this answers your question but it should point you in the right direction.
I couldn't make much sense of your code. I've produced a 15 row x 4 column grid.
The 4th column is a message that the 3 fields next to it are 'OK' or if not indicate the problem. The validation is run on the whole grid for each keypress. If this is too slow a validate button could launch the validation instead.
import tkinter as tk
from tkinter import ttk
def rec(): return {'lo': 0, 'hi': 0, 'step': 0, 'ok': '' }
root = tk.Tk()
root.title('SO Question')
def entry(id, ent_dict, var_dict, v=0):
""" Add an Entry Widget to the root, with associated StringVar."""
var_dict[id] = tk.StringVar()
var_dict[id].set(str(v))
ent_dict[id] = ttk.Entry(root, textvariable= var_dict[id], width = 10 )
return ent_dict[id]
def do_validate(lo, hi, step):
""" Return OK if lo, hi and step are consistent else an error string. """
if lo < hi and step < hi: return 'OK'
txt = ''
if lo >= hi:
txt = 'lo >= hi. '
if step >= hi:
txt += 'step >= hi.'
return txt
def conv(txt):
""" Convert text to float. Return 0.0 if not valid float e.g "" or 'a' """
try:
return float(txt)
except ValueError:
return 0.0
def oklabel(ent_dict, var_dict):
""" Add an OK Label to a row. """
lo = conv(var_dict['lo'].get())
hi = conv(var_dict['hi'].get())
step = conv(var_dict['step'].get())
var_dict['ok'] = tk.StringVar()
var_dict['ok'].set(do_validate(lo, hi, step))
ent_dict['ok'] = ttk.Label(root, textvariable = var_dict['ok'], width = -17)
return ent_dict['ok'] # Return the Label object for gridding.
def do_check(*args):
""" Loop through the rows setting the validation string in each one. """
for var_dict in stringvars:
lo = conv(var_dict['lo'].get())
hi = conv(var_dict['hi'].get())
step = conv(var_dict['step'].get())
var_dict['ok'].set(do_validate(lo, hi, step))
# Add column labels
ttk.Label(root, text='Minimums').grid(row=0, column=0)
ttk.Label(root, text =' Maximums').grid(row=0, column=1)
ttk.Label(root, text='Increment').grid(row=0, column=2)
ttk.Label(root, text='Valid').grid(row=0, column=3)
# Create containers for he Entries and Stringvars
entries =[]
stringvars = []
# Add 15 rows of Entries / Validation Labels to the UI.
for row in range(1, 16):
tempe=rec()
tempv=rec()
entry('lo', tempe, tempv, 0).grid(row = row, column=0)
entry('hi', tempe, tempv, 0).grid(row = row, column=1)
entry('step', tempe, tempv, 0).grid(row = row, column=2)
oklabel(tempe, tempv).grid(row = row, column = 3)
entries.append(tempe)
stringvars.append(tempv)
# Bind do_check to all Entry widgets.
root.bind_class('TEntry', '<KeyPress>', do_check, add='+')
root.bind_class('TEntry', '<BackSpace>', do_check, add='+')
root.bind_class('TEntry', '<Delete>', do_check, add='+')
root.mainloop()
In the past I've got stuck trying to validate multiple fields by not allowing inconsistent entries. It is difficult for users to follow what is required to correct fields. They have to work in the correct order. e.g. lo = 100, hi = 9, and step = 1. Should the UI allow the last zero in 100 to be deleted, leaving 10 which is gt 9?
This could be extended to activate a 'Next' button only if all rows are OK.
Edit 1 - Response to Comment
This has a function to create and activate each row of the display. Each row has it's own variables and checking function. They are triggered by the trace on the three Entry StringVars, there's no need to use validate.
import tkinter as tk
from tkinter import ttk
def to_float(txt):
""" Safely convert any string to a float. Invalid strings return 0.0 """
try:
return float(txt)
except ValueError:
return 0.0
def row_n( parent, n, init_show = 0 ):
""" Create one row of the display. """
# tk.Variables
v_show = tk.IntVar()
v_min = tk.StringVar()
v_max = tk.StringVar()
v_incr = tk.StringVar()
v_message = tk.StringVar()
# Initialise variables
v_min.set('0')
v_max.set('1')
v_incr.set('1') # Can the increment be zero?
v_show.set(init_show)
v_message.set("OK")
def do_trace(*args):
""" Runs every time any of the three Entries change value.
Sets the message to the appropriate text.
"""
lo = to_float(v_min.get())
hi = to_float(v_max.get())
inc = to_float(v_incr.get())
if lo < hi and inc <=hi:
v_message.set('OK')
else:
txt = ''
if lo >= hi:
txt += 'Min >= Max'
if inc > hi:
if len(txt): txt += ' & '
txt += 'Incr > Max'
v_message.set(txt)
# Set trace callback for changes to the three StringVars
v_min.trace('w', do_trace)
v_max.trace('w', do_trace)
v_incr.trace('w', do_trace)
def activation(*args):
""" Runs when the tickbox changes state """
if v_show.get():
e_min.grid(row = n, column = 1)
e_max.grid(row = n, column = 2)
e_inc.grid(row = n, column = 3)
message.grid(row = n, column = 4)
else:
e_min.grid_remove()
e_max.grid_remove()
e_inc.grid_remove()
message.grid_remove()
tk.Checkbutton(parent,
text = 'Structure Coefficient {} :'.format(n),
variable = v_show, command = activation ).grid(row = n, column = 0)
e_min = tk.Entry(parent, width=5, textvariable = v_min)
e_max =tk.Entry(parent, width=5, textvariable = v_max)
e_inc = tk.Entry(parent, width=5, textvariable = v_incr)
message = tk.Label(parent, width=-15, textvariable = v_message)
activation()
return { 'Min': v_min, 'Max': v_max, 'Inc': v_incr }
def show_results():
print('Min Max Inc')
for row in rows:
res = '{} {} {}'.format(row['Min'].get(), row['Max'].get(), row['Inc'].get())
print( res )
root = tk.Tk()
root.title('SO Question')
ttk.Label(root, text='Minimums').grid(row=0, column=1)
ttk.Label(root, text =' Maximums').grid(row=0, column=2)
ttk.Label(root, text='Step', width = 5 ).grid(row=0, column=3)
ttk.Label(root, text='Valid', width = 15 ).grid(row=0, column=4)
rows = []
for r in range(1,16):
rows.append(row_n(root, r, init_show=r%3 == 0 ))
tk.Button(root, command=show_results, text = ' Show Results ').grid(column=1, pady = 5)
root.mainloop()
This is another approach. Does this help.
Here's another suggestion. Incorporate the Label and Entry in the row-n function. Include activating / disabling the Entry in the activate function. The row_n function is executed in a loop through a list of the descriptions you want.
import tkinter as tk
row_names = [ "Structure Coefficient(N)", "Chlorophyll Content(Cab) (µg.cm-2)",
"Carotenoid content(Car) (µg.cm-2)", "Brown pigment content(Cbrown)(arbitrary units)"]
def row_n(parent, desc, n, init_show = 0 ):
""" Create one row of the display. """
# tk.Variables
v_show = tk.IntVar()
v_min = tk.StringVar()
v_max = tk.StringVar()
v_incr = tk.StringVar()
v_fixed = tk.StringVar() # New StringVar
v_message = tk.StringVar()
v_show.set(init_show)
v_message.set("OK")
def do_trace(*args):
""" Runs every time any of the three Entries change value.
Sets the message to the appropriate text.
"""
lo = to_float(v_min.get())
hi = to_float(v_max.get())
inc = to_float(v_incr.get())
if lo < hi and inc <=hi:
v_message.set('OK')
else:
txt = ''
if lo >= hi:
txt += 'Min >= Max'
if inc > hi:
if len(txt): txt += ' & '
txt += 'Incr > Max'
v_message.set(txt)
# Set trace callback for changes to the three StringVars
v_min.trace('w', do_trace)
v_max.trace('w', do_trace)
v_incr.trace('w', do_trace)
def activation(*args):
""" Runs when the tickbox changes state """
if v_show.get():
e_min.grid(row = n, column = 8)
e_max.grid(row = n, column = 9)
e_inc.grid(row = n, column = 10)
message.grid(row = n, column = 11)
e_fixed.config(state = 'disabled') # Disable the base Entry
else:
e_min.grid_remove()
e_max.grid_remove()
e_inc.grid_remove()
message.grid_remove()
e_fixed.config(state = 'normal') # Enable the base Entry Widget
tk.Label(parent, text = desc ).grid(row = r+1, column = 4 ) # Add the desc. Label
e_fixed = tk.Entry(parent, textvariable = v_fixed) # Add the new Entry widget
e_fixed.grid(row = r+1, column = 5)
tk.Checkbutton(parent,
text = ' '.format(n),
variable = v_show, command = activation ).grid(row = n, column = 6)
e_min = tk.Entry(parent, width=5, textvariable = v_min)
e_min.config(font=('Candara', 15))
e_max =tk.Entry(parent, width=5, textvariable = v_max)
e_max.config(font=('Candara', 15))
e_inc = tk.Entry(parent, width=5, textvariable = v_incr)
e_inc.config(font=('Candara', 15))
message = tk.Label(parent, width=-15, textvariable = v_message)
message.config(font=('Candara', 15))
activation()
return { 'Min': v_min, 'Max': v_max, 'Inc': v_incr, 'Fixed': v_fixed }
# The 'Fixed' field added to the dictionary to return
def print_row(row):
fmt = 'Min: {}, Max: {}, Inc: {}, Fixed: {}'
print(fmt.format(
row['Min'].get(), row['Max'].get(), row['Inc'].get(), row['Fixed'].get()
))
def to_float(txt):
""" Safely convert any string to a float. Invalid strings return 0.0 """
try:
return float(txt)
except ValueError:
return 0.0
# GUI Start
root = tk.Tk()
root.title('Validation wth Trace')
# Header Labels
tk.Label(root,text="Min").grid(row=0,column=8,padx=4,pady=4)
tk.Label(root,text="Max").grid(row=0,column=9,padx=4,pady=4)
tk.Label(root,text="Inc").grid(row=0,column=10,padx=4,pady=4)
# Body of rows
rows = []
for r, r_text in enumerate(row_names):
rows.append(row_n( root, r_text, r+1))
root.mainloop()
print("Strings in the Entry fields")
for r, row in enumerate(rows):
print('Row: ', r, 'Data:', end=' ')
print_row(row)
HTH. Seeing your code in the inked question you may prefer to make row_n a class.