I am aware that it is possible to trace the changes of, say, the entered value in an Entry widget by using e.g. a StringVar and a variable observer like Trace. Is it possible to also trace the state of a widget? Let's say we have the code:
from tkinter import *
class My_Window:
def __init__(self, root):
self.button1 = Button(root, text="Enter", command = self.disable_entrybox)
self.get_info_box1 = Entry(root)
self.button2 = Button(root, text="Enter", command = self.disable_entrybox)
self.get_info_box2 = Entry(root)
self.button1.pack()
self.get_info_box1.pack()
self.button2.pack()
self.get_info_box2.pack()
self.get_info_box2.config(state="disable")
def disable_entrybox(self):
x = self.get_info_box1.get()
self.get_info_box1.config(state="disable")
root = Tk()
my_window = My_Window(root)
root.mainloop()
And I want to trace if get_info_box1is disabled or not, and if it's disabled, change the state of get_info_box2 to "normal". Is there any way to do this?
Related
My aim is to generate a window with a button "NewWindow" on it. If I press the button, the program should open a new window. This window I stored in a class "NewWindow" to quickly reproduce it.
In this "NewWindow" I have another button. If I press it the label of basic window should be updated and the window "NewWindow" should be closed automatically.
Here is my code:
from tkinter import *
class NewWindow(Toplevel):
def __init__(self, master = None):
super().__init__(master = master)
self.title('NewWindow')
self.lb = Label(self, text='Hello')
self.lb.grid(column=0, row=0, columnspan=1)
self.bt1 = Button(self, text="apply Hello", command= self.bt_press)
self.bt1.grid(column=0, row=1)
def bt_press(self):
window.basic_lb.text = "Hello"
window = Tk()
def new_Editor():
a = NewWindow(window)
window.title("BasicWindow")
window.basic_lb = Label(window, text='None')
window.basic_lb.grid(column=0, row=0, columnspan=1)
window.basic_bt = Button(window, text="NewWindow", command=new_Editor)
window.basic_bt.grid(column=0, row=1)
window.mainloop()
Problems:
At start both windows NewWindow and BasicWindow are displayd. I only want to open BasicWindow and NewWindow should be opened after button basic_bt is clicked. How can I solve it? (already solved by commed below)
Why the label text in basic_lb did not get some update after pressing self.bt1?
How is it possible to close NewWindow with use of bt_press method?
You have a few typos/errors in your code that are casuing some of your problems. As #Tim said, when you pass a function to a command like command=function(), it will be called on runtime, not when the button is pressed. You need to pass the function handle to the command, command=function. You got around this by using a lambda function in your button command, but it is easier to just have command=self.bt_press
Answering your second question, window.basic_lb.text = "Hello" is not how you change the text in a tkinter Label, use <Label>.config(text="Hello"). You also should use self.master and define self.master = master in __init__ instead of just using window, because while you can access window due to it not being defined in local scope, it's better to explicitly define it.
You can close a window using window.destroy().
Your working code is now:
from tkinter import *
class NewWindow(Toplevel):
def __init__(self, master = None):
super().__init__(master = master)
self.title('NewWindow')
self.master = master
self.lb = Label(self, text='Hello')
self.lb.grid(column=0, row=0, columnspan=1)
self.bt1 = Button(self, text="apply Hello", command=self.bt_press)
self.bt1.grid(column=0, row=1)
def bt_press(self):
self.master.basic_lb.config(text="Hello")
self.destroy()
window = Tk()
def new_Editor():
a = NewWindow(window)
window.title("BasicWindow")
window.basic_lb = Label(window, text='None')
window.basic_lb.grid(column=0, row=0, columnspan=1)
window.basic_bt = Button(window, text="NewWindow", command=new_Editor)
window.basic_bt.grid(column=0, row=1)
window.mainloop()
Why in this code when clicking a button when a new window opens, all the radio buttons are selected?
class CodeButton:
def __init__(self, root):
self.btn = Button(root, text="Code",width=20, height=1,bg="white", fg="black")
self.btn.bind("<Button-1>", make_code_window)
self.btn.pack()
def make_code_window(event):
new_root = Toplevel()
new_root.minsize(width=300, height=300)
var = IntVar()
var.set(0)
for i in range(8):
Radiobutton(new_root, text=str(i), variable=var, value=i).pack()
def main():
root = Tk()
root.minsize(width=400, height=250)
CodeButton(root)
root.mainloop()
It's got something to do with storing the IntVar in a local variable in the function that will be discarded as soon as the make_code_window() function returns. You can fix the problem by making the IntVar an attribute of the new_root window widget, so it will exist at least as long as the widget using it does.
The code in your example isn't very realistic in the sense that typically one would want to use the current value of the IntVar for something somewhere else in the Python code, but that wouldn't be possible since it's only stored temporarily in local variable which exists only during the execution of the function that created it.
try:
from tkinter import *
except ImportError: # Python 2
from Tkinter import *
class CodeButton:
def __init__(self, root):
self.btn = Button(root, text="Code",width=20, height=1,bg="white", fg="black")
self.btn.bind("<Button-1>", make_code_window)
self.btn.pack()
def make_code_window(event):
new_root = Toplevel()
new_root.minsize(width=300, height=300)
var = new_root.var = IntVar() # changed
var.set(0)
for i in range(8):
Radiobutton(new_root, text=str(i), variable=var, value=i).pack()
def main():
root = Tk()
root.minsize(width=400, height=250)
CodeButton(root)
root.mainloop()
main()
(Following-up on the discussion we were having in the comments section of my other answer.)
Yes, passing the IntVar as an argument to the event handler function is a little tricky—in fact it's sometimes called The extra arguments trick. ;-)
Here's an example of applying it to your code:
try:
from tkinter import *
except ImportError: # Python 2
from Tkinter import *
class CodeButton:
def __init__(self, root):
self.btn = Button(root, text="Code",width=20, height=1,bg="white", fg="black")
self.btn.bind("<Button-1>",
# Extra Arguments Trick
lambda event, var=root.var: make_code_window(event, var))
self.btn.pack()
def make_code_window(event, var): # note added "var" argument
new_root = Toplevel()
new_root.minsize(width=300, height=300)
var.set(-99) # deselect by using value not associated with any RadioButtons
for i in range(8):
Radiobutton(new_root, text=str(i), variable=var, value=i).pack()
def main():
root = Tk()
root.minsize(width=400, height=250)
root.var = IntVar() # create it here to give access to it in the rest of your code
CodeButton(root)
root.mainloop()
main()
I'm trying to use an Entry field to get manual input, and then work with that data.
All sources I've found claim I should use the get() function, but I haven't found a simple working mini example yet, and I can't get it to work.
I hope someone can tel me what I'm doing wrong. Here's a mini file:
from tkinter import *
master = Tk()
Label(master, text="Input: ").grid(row=0, sticky=W)
entry = Entry(master)
entry.grid(row=0, column=1)
content = entry.get()
print(content) # does not work
mainloop()
This gives me an Entry field I can type in, but I can't do anything with the data once it's typed in.
I suspect my code doesn't work because initially, entry is empty. But then how do I access input data once it has been typed in?
It looks like you may be confused as to when commands are run. In your example, you are calling the get method before the GUI has a chance to be displayed on the screen (which happens after you call mainloop.
Try adding a button that calls the get method. This is much easier if you write your application as a class. For example:
import tkinter as tk
class SampleApp(tk.Tk):
def __init__(self):
tk.Tk.__init__(self)
self.entry = tk.Entry(self)
self.button = tk.Button(self, text="Get", command=self.on_button)
self.button.pack()
self.entry.pack()
def on_button(self):
print(self.entry.get())
app = SampleApp()
app.mainloop()
Run the program, type into the entry widget, then click on the button.
You could also use a StringVar variable, even if it's not strictly necessary:
v = StringVar()
e = Entry(master, textvariable=v)
e.pack()
v.set("a default value")
s = v.get()
For more information, see this page on effbot.org.
A simple example without classes:
from tkinter import *
master = Tk()
# Create this method before you create the entry
def return_entry(en):
"""Gets and prints the content of the entry"""
content = entry.get()
print(content)
Label(master, text="Input: ").grid(row=0, sticky=W)
entry = Entry(master)
entry.grid(row=0, column=1)
# Connect the entry with the return button
entry.bind('<Return>', return_entry)
mainloop()
*
master = Tk()
entryb1 = StringVar
Label(master, text="Input: ").grid(row=0, sticky=W)
Entry(master, textvariable=entryb1).grid(row=1, column=1)
b1 = Button(master, text="continue", command=print_content)
b1.grid(row=2, column=1)
def print_content():
global entryb1
content = entryb1.get()
print(content)
master.mainloop()
What you did wrong was not put it inside a Define function then you hadn't used the .get function with the textvariable you had set.
you need to put a textvariable in it, so you can use set() and get() method :
var=StringVar()
x= Entry (root,textvariable=var)
Most of the answers I found only showed how to do it with tkinter as tk. This was a problem for me as my program was 300 lines long with tons of other labels and buttons, and I would have had to change a lot of it.
Here's a way to do it without importing tkinter as tk or using StringVars. I modified the original mini program by:
making it a class
adding a button and an extra method.
This program opens up a tkinter window with an entry box and an "Enter" button. Clicking the Enter button prints whatever is in the entry box.
from tkinter import *
class mini():
def __init__(self):
master = Tk()
Label(master, text="Input: ").grid(row=0, sticky=W)
Button(master, text='Enter', command=self.get_content).grid(row=1)
self.entry = Entry(master)
self.entry.grid(row=0, column=1)
master.mainloop()
def get_content(self):
content = self.entry.get()
print(content)
m = mini()
I'm trying to use an Entry field to get manual input, and then work with that data.
All sources I've found claim I should use the get() function, but I haven't found a simple working mini example yet, and I can't get it to work.
I hope someone can tel me what I'm doing wrong. Here's a mini file:
from tkinter import *
master = Tk()
Label(master, text="Input: ").grid(row=0, sticky=W)
entry = Entry(master)
entry.grid(row=0, column=1)
content = entry.get()
print(content) # does not work
mainloop()
This gives me an Entry field I can type in, but I can't do anything with the data once it's typed in.
I suspect my code doesn't work because initially, entry is empty. But then how do I access input data once it has been typed in?
It looks like you may be confused as to when commands are run. In your example, you are calling the get method before the GUI has a chance to be displayed on the screen (which happens after you call mainloop.
Try adding a button that calls the get method. This is much easier if you write your application as a class. For example:
import tkinter as tk
class SampleApp(tk.Tk):
def __init__(self):
tk.Tk.__init__(self)
self.entry = tk.Entry(self)
self.button = tk.Button(self, text="Get", command=self.on_button)
self.button.pack()
self.entry.pack()
def on_button(self):
print(self.entry.get())
app = SampleApp()
app.mainloop()
Run the program, type into the entry widget, then click on the button.
You could also use a StringVar variable, even if it's not strictly necessary:
v = StringVar()
e = Entry(master, textvariable=v)
e.pack()
v.set("a default value")
s = v.get()
For more information, see this page on effbot.org.
A simple example without classes:
from tkinter import *
master = Tk()
# Create this method before you create the entry
def return_entry(en):
"""Gets and prints the content of the entry"""
content = entry.get()
print(content)
Label(master, text="Input: ").grid(row=0, sticky=W)
entry = Entry(master)
entry.grid(row=0, column=1)
# Connect the entry with the return button
entry.bind('<Return>', return_entry)
mainloop()
*
master = Tk()
entryb1 = StringVar
Label(master, text="Input: ").grid(row=0, sticky=W)
Entry(master, textvariable=entryb1).grid(row=1, column=1)
b1 = Button(master, text="continue", command=print_content)
b1.grid(row=2, column=1)
def print_content():
global entryb1
content = entryb1.get()
print(content)
master.mainloop()
What you did wrong was not put it inside a Define function then you hadn't used the .get function with the textvariable you had set.
you need to put a textvariable in it, so you can use set() and get() method :
var=StringVar()
x= Entry (root,textvariable=var)
Most of the answers I found only showed how to do it with tkinter as tk. This was a problem for me as my program was 300 lines long with tons of other labels and buttons, and I would have had to change a lot of it.
Here's a way to do it without importing tkinter as tk or using StringVars. I modified the original mini program by:
making it a class
adding a button and an extra method.
This program opens up a tkinter window with an entry box and an "Enter" button. Clicking the Enter button prints whatever is in the entry box.
from tkinter import *
class mini():
def __init__(self):
master = Tk()
Label(master, text="Input: ").grid(row=0, sticky=W)
Button(master, text='Enter', command=self.get_content).grid(row=1)
self.entry = Entry(master)
self.entry.grid(row=0, column=1)
master.mainloop()
def get_content(self):
content = self.entry.get()
print(content)
m = mini()
So I am currently trying to create a button on a GUI that will let the user generate a new entry field.
I have no idea how to do this. I'm guessing that it will require a lambda function, but apart from that, I have no idea.
Here's the basic code I have so far:
from tkinter import *
class prac:
def autoAddWidget(self,frame,x,y):
self.entryField = Entry(frame,text="Entry Field")
self.entryField.grid(row=x, column=y)
#lambda function?
def __init__(self, master):
frame = Frame(master, width=60, height=50)
frame.pack()
x=1
self.addWidgetButton = Button(frame, text="Add new widget", command=self.autoAddWidget(frame, x,0))
self.addWidgetButton.grid(row=0, column=0)
x+=1
root = Tk()
app = prac(root)
root.mainloop()
Would appreciate the help.
Thanks
You're passing to the command argument result from the method self.autoAddWidget(frame, x,0) not method itself. You have to pass there a reference to a callable object, a function that will be called when the event occurs. Please check a documentation next time before you ask the question.
Ok, I fixed the code, now it works:
from tkinter import *
class Prac:
def autoAddWidget(self):
self.entryField = Entry(self.frame,text="Entry Field")
self.entryField.grid(row=self.x, column=0)
self.x+=1
def __init__(self, master):
self.frame = Frame(master, width=60, height=50)
self.frame.pack()
self.x=1
self.addWidgetButton = Button(self.frame, text="Add new widget", command=self.autoAddWidget)
self.addWidgetButton.grid(row=0, column=0)
root = Tk()
app = Prac(root)
root.mainloop()