I am trying to make a label appear if the condition of my entry (textbox) is met. Unfortunately I cannot see anything when I am pressing the button on the testing. Here is what I have:
from tkinter import *
main= Tk()
firstname=Entry(main).place(x=30, y=50)
def register():
if any(i.isdigit() for i in firstname.get())== True:
print (Label(main,text='no numbers please').place(x=30, y=180))
else:
print(Label(main, text='pass').place(x=40, y=170))
register=Button(main,text='REGISTER', command= lambda :register).place(x=300, y=200)
There are at least three problems with your code. The first is in how you define the button's command:
register=Button(main,text='REGISTER', command= lambda :register)
When you do command=lambda: register, you're telling the button "when you're clicked run the code register". register all by itself does nothing. Since register is (supposed to be) a function, you need to call it like register() inside the lambda.
Since you aren't passing any values to the function, the lambda is completely unnecessary. Instead, just directly reference the function: command=register without the parenthesis.
The second problem is that you've used the name register to be two different things: a function and a reference to a widget. Because of the ordering of the code, command=register or command=lambda: register() will try to call the button rather than the function.
The third problem is a very, very common mistake. In python, when you do x = y().z(), x is given the value of z(). Thus, register = Button(...).pack(...) returns the value of pack(...) and pack (and grid and place) always returns None.
Therefore, you've set register to None, and when you try to call it you get NoneType object is not callable.
In addition to fixing the command, you need to pick a different name for either the function or the button. And you should not be calling place (or pack or grid) in-line with creating the widget. They should be separate steps.
So, putting that all together, you need to define firstname like this so that firstname is not None:
firstname=Entry(main)
firstname.place(x=30, y=50)
And then you need to define the button like this:
register_button = Button(main,text='REGISTER', command= register)
register_button.place(x=300, y=200)
Related
def openCipher():
cipher = Toplevel()
cipher.title("decryptt - CIPHER")
cipherLabel = Label(cipher, text="cipher").pack()
cipherEntry = Entry(cipher, width=20, borderwidth=5) #separating pack now allows you to use get() on this
cipherEntry.pack()
cipherChoices = [
("Binary","bcipher"),
("Caesar","ccipher"),
("Hexadecimal","hcipher"),
("Atbash","acipher"),
("Letter-to-Number","lcipher")
]
cipherType = StringVar()
cipherType.set("Binary")
for text, cipherChoice in cipherChoices:
Radiobutton(cipher, text=text, variable=cipherType, value=cipherChoice).pack()
cipherButton = Button(cipher, text="Cipher", padx=10, pady=5, command=lambda:[ciphering(cipherEntry.get()), ciphering(cipherChoice.get())]).pack() #lambda allows you to pass arguments to functions
quitButton = Button(cipher, text="Exit Cipher", padx=10, pady=5, command=cipher.destroy).pack()
# This is the function that is suppose to split the input from cipherEntry into individual characters in an array.
def ciphering(entry,choice):
ciphering = Toplevel() #needed to add new label to
cipherLabeling = Label(ciphering, text = "You have inputted " + entry).pack() #couldn’t add a list to string like that, nor use get() on a list, changed to just use the string
seperatedWord = list(entry)
cipherLabeling = Label(ciphering, text = seperatedWord[2]).pack()
seperatedWordLength = len(seperatedWord)
cipherLabeling = Label(ciphering, text = seperatedWordLength).pack()
selection = Label(ciphering, text = choice).pack()
Above is part of the code I have for my ciphering app I am making in Tkinter. Took out the less important parts.
Basically, what is being created in OpenCipher() functions is an entry box that is named cipherEntry. Then there are radio buttons with different names of different ciphers and the value and variable of each radio button is the same as each other for that radio button. Then there is another button that takes whatever cipherEntry is and brings it to another window using the ciphering() function.
What I need to know is how do I also get whatever the value and/or variable of whatever radio button they have selected to that window using the same button they pressed to get to that window ( cipherButton ). Because I want to then use their selection and input to know what cipher type they want their input to be changed to. I already have the function for it sorted.
I have tried using cipherType, cipherChoice, cipherChoices but have no idea how to get them both in there. With the current code above. It works as if there was no second command. It totally disregards whatever selection I put in and the 'selection' label widget doesn't display their choice. I have also made each variable a global to see if that did anything but no luck.
I would really appreciate any assistance :)
First of all, the code should give an error because def ciphering(entry,choice) expects two positional arguments to be passed at the same time. Even after fixing that, it should give another error because cipherChoice is a string(from the list of tuples) and does not have a get attribute.
The thing to focus on here is:
command=lambda: [ciphering(cipherEntry.get()), ciphering(cipherChoice.get())]
When you say something like lambda: [func1(arg1),func1(arg2)] you are set to executing the function func1 and again func1 one after the other(so twice). What you want is to pass multiple arguments to the same function just using a normal lambda without any list, like:
command=lambda: ciphering(cipherEntry.get(), cipherType.get())
Also notice how I changed cipherChoice.get() to cipherType.get(), it is because cipherChoice is a string and also does not have a get attribute, but the value of the radiobutton should be acquired from the associated tkinter variable(StringVar) only. So you have to use cipherType.get()
I'm trying to build a listbox using Tkinter and receive the selected option by clicking it.
import Tkinter as tk
from Tkinter import *
root = tk.Tk()
lst=Listbox(root, height=30, width=50)
lst.insert(1, "hy")
lst.insert(2, "hello")
lst.insert(3, "hey")
lst.pack()
sel = lst.curselection()
print sel
root.mainloop()
However, when I run the code it prints me an empty tuple before I pressed any choise.
Does someone know how to get the selected choise after I press one and not right after I run it?
Thanks a lot :)
You are getting the selection about a millisecond after creating the widget, well before the user has a chance to see the UI much less interact with it.
GUI programs are event based, meaning that things happen in response to events. Events are things like clicking buttons, inserting data into input widgets, and selecting items from listboxes.
You need to do one of two things: create a button or other widget which will get the selected item, or configure it so that a function is called whenever an item is selected.
No matter which solution you use, you will need a function that ultimately calls the curselection method of the listbox to get a list of indices. You can then call the get method to get the selected item or items.
Here's a function definition that will print the selected item, or print "no selection" if nothing is selected. So that it can be resused without modification. we'll define it to take the listbox as an argument.
Note: this example assumes the widget only supports a single select, to keep it simple:
def print_selection(listbox):
selection = listbox.curselection()
if selection:
print(f"selected item: {listbox.get(selection[0])}")
else:
print("nothing is selected")
Using a button
To call this from a button is straight-forward. We just create a button after we create the listbox, and use the command attribute to call the function. Since the function we wrote earlier needs a parameter, we'll use lambda to create a temporary function for the button.
button = tk.Button(root, text="Print Selected Item", command=lambda: print_selection(lst))
button.pack()
Calling the function when the selection is made
To call the function whenever the user changes the selection, we can bind a function to the <<ListboxSelect>> event. We'll create a separate function for this, and then pull the widget from the event object that is automatically passed to the function.
def print_callback(event):
print_selection(event.widget)
lst.bind("<<ListboxSelect>>", print_callback)
First of all, the reason you are getting an empty tuple is because you have executed the statements:
sel = lst.curselection()
print(sel)
before you have executed the root.mainloop()
Secondly, your setup for listbox fails to include a StringVar variable to hold your list.
Once the variable has been defined, you should be able to use the .insert statements to add your list items one at a time, or you can initialize the StringVar variable using a .set('hy', 'hello', 'hey') command.
To provide a return of a selected variable, you must incorporate an event handler to determine the list position selected onclick or some other triggering method.
For a pretty clear explanation of these characteristics check here
I am currently a novice in python and I'm trying to make a label switch from one image to another by clicking a next button. Here's my code:
from tkinter import *
def next1():
global slide
slide=1
if slide==1:
bglabel.config(image=bg1)
elif slide==2:
bglabel.config(image=bg2)
slide+=1
window.update()
window=Tk()
window.geometry("1500x750+0+0")
bg1=PhotoImage(file="backslide1.png")
bg2=PhotoImage(file="backslide2.png")
nextbutton=PhotoImage(file="next.png")
bglabel=Label(window, image=bg1)
bglabel.place(x=600,y=200)
nextbutton1=Button(window, image=nextbutton, bd=0, command=next1())
window.bind('<Button-1>', next1())
I sat for a good hour or so trying to tamper with the slide variable (trying to declare it before def, removing global, changing value, changing where slide+=1 is, etc) but one of two things always happens; either it's stuck on bg1 with the button clicking but doing nothing, or jumping straight to bg2. I've also tried splitting next1 into two different def's, one for variable tracking, one for switching bglabel, but still the same output. Please help.
(Also, will that window.bind be trouble as I continue to add buttons? If so please let me know how to do it correctly.)
As you mentioned, one 'error' that occurs is that the image immediately jumps to image bg2. This is the line causing that:
nextbutton1=Button(window, image=nextbutton, bd=0, command=next1())
More specifically, where you declare the command associated with the button:
command=next1()
With the enclosed brackets, you're calling the function next1 i.e. as soon as the button is created, run the specified function.
To solve this, just remove the pair of brackets:
nextbutton1=Button(window, image=nextbutton, bd=0, command=next1)
The same goes for your key binding. This way, the button/key now has a reference to the function - it knows what function to run and will run it when the specified action is performed.
More about the key binding...
When you use bind to assign a key to run a function, whatever function that is to be run needs to be made aware as such. Currently, the next function you are trying to bind is given no indication that it can be called using a keyboard button event. To fix that, we set a default parameter in next specifying the event:
def next1(event=None):
#rest of function code here
window.bind('<Button-1>', lambda event: next(event))
Setting a default parameter, event=None, basically means if no value forevent was passed to the function from whatever called it, set it to None by default (in that sense, you can choose to set it to whatever by default). Using lambda for the key bind in this way allows us to pass parameters to functions. We specify what parameter(s) we want to pass to the function and then specify the function, with the parameter(s) enclosed in brackets.
You need to provide the function, not the result of the function. So no parenthesis. Like this:
nextbutton1=Button(window, image=nextbutton, bd=0, command=next1)
Also remove the window.bind line, and your loop logic is broken. "slide" is always 1 since you set that in the function. Are you trying to cycle between the 2 images with every click? If so use itertools.cycle:
from tkinter import *
from itertools import cycle
def next1():
bglabel.config(image=next(bgimages))
window=Tk()
window.geometry("1500x750+0+0")
bg1=PhotoImage(file="backslide1.png")
bg2=PhotoImage(file="backslide2.png")
bgimages = cycle([bg1, bg2])
nextbutton=PhotoImage(file="next.png")
bglabel=Label(window)
bglabel.place(x=600,y=200)
next1() # set the first image
nextbutton1=Button(window, image=nextbutton, bd=0, command=next1)
nextbutton1.pack()
window.mainloop()
(totally untested since i don't have your images).
This question already has answers here:
Creating functions (or lambdas) in a loop (or comprehension)
(6 answers)
Closed 6 months ago.
I have made a simple "program launcher" in Python. I have a tab delimited text file, with, at the moment, just:
notepad c:\windows\notepad.exe
write c:\windows\write.exe
The program reads the textfile and creates an array of objects. Each object has a name property (e.g. notepad) and a route property (e.g. C:\windows\notepad.exe). Then, for each object, a button should be made with the correct name on the button, and clicking the button should execute the correct program using the route.
The program very nearly works. Indeed, the array of objects is formed correctly, because the for loop correctly prints out two different program names, and two different routes. The problem is that both buttons, although labeled correctly, launch the write program ! I believe the problem is arising somewhere in the callback, but my Python knowledge just isn't developed enough to solve this! As you can see from my code below, I have tried an "inline" callback, and with a "runprog" function defined. They both give the same outcome.
Your help would be appreciated.
import Tkinter as tk
import subprocess
class MyClass:
def __init__(self, thename,theroute):
self.thename=thename
self.theroute=theroute
myprogs = []
myfile = open('progs.txt', 'r')
for line in myfile:
segmentedLine = line.split("\t")
myprogs.append(MyClass(segmentedLine[0],segmentedLine[1]))
myfile.close()
def runprog(progroute):
print(progroute)
subprocess.call([progroute])
root = tk.Tk()
button_list=[]
for prog in myprogs:
print(prog.thename)
print(prog.theroute)
button_list.append(tk.Button(root, text=prog.thename, bg='red', command=lambda: runprog(prog.theroute)))
# button_list.append(tk.Button(root, text=prog.thename, bg='red', command= lambda: subprocess.call(prog.theroute)))
# show buttons
for button in button_list:
button.pack(side='left', padx=10)
root.mainloop()
Change your command to look like this:
tk.Button(..., command=lambda route=prog.theroute: runprog(route))
Notice how the lambda has a keyword argument where you set the default value to the route you want to associate with this button. By giving the keyword arg a default value, you are "binding" this value to this specific lambda.
Another option is to use functools.partial, which many people find a little less intimidating than lambda. With this, your button would look like this:
import functools
...
tk.Button(..., command=functools.partial(runprog,route)
A third option is to move the "runprog" function to the class instead of in the main part of your program. In that case the problem becomes much simpler because each button is tied specifically to a unique object.
tk.Button(..., command=prog.runprog)
Just change this line:
button_list.append(tk.Button(root, text=prog.thename, bg='red', command=lambda: runprog(prog.theroute)))
to:
button_list.append(tk.Button(root, text=prog.thename, bg='red',
command= (lambda route:(lambda: runprog(route))) (prog.theroute)))
Reasoning: when you create a lambda function (or any other function within a function), it does have access (in Python 2, read-only access) to the variables in the outer function scope. However, it does access the "live" variable in that scope - when the lambda is called, the value retrieved from "prog" will be whatever "prog" means at that time, which in this case will be the last "prog" on your list (since the user will only click a button long after the whole interface is built)
This change introduces an intermediary scope - another function body into which the current "prog" value is passed - and prog.theroute is assigned to the "route" variable in the moment the expression is run. That is done once for each program in the list. The inner lambda which is the actual callback does use the "route" variable in the intermediate scope - which holds a different value for each pass of the loop.
I have a set of methods in my program the use Tkinter that don't behave like I thought they would. I want to be able to push a button in the window and have more text fields appear, and be able to return a list of the results in the text fields. Here is what I have:
def expandChoice(self):
root = Tk()
choices = []
plusButton = Button (root, text='+', command=self.addChoice(root, choices))
plusButton.pack()
quitButton = Button (root, text='Ok', command=root.destroy )
quitButton.pack()
root.mainloop()
return choices
def addChoice(self, parent, variables):
variables.append(StringVar())
text = Entry(parent, textvariable=variables[len(variables)-1])
text.pack()
What happens is that one text field appears when the window loads (above the buttons), and the plus button does nothing. What am I doing wrong? It seems like the addChoice method get called automatically when the first button's constructor is called and then doesn't work after that.
The command option takes a reference to a callable. You, however, are calling addChoice immediately, then assigning what that retuns (None) to the command option.
You need to do something like Button(...command=self.addChoice)
If you need to pass arguments you will need to either use a lambda or functools.partial. Search for either of those on this site -- variations of this question has been asked and answered many times on SO.