how to delete a tkinter window using lambda with a button - python

I am doing a project that uses many tkinter buttons on different windows and I want to be able to close a window and run a function at the same time using lambda but the window doesn't close. If I stop using lambda it works again. I tried in repl and in idle but got the same result. This works:
tk = Tk()
tk.geometry('500x300')
def function():
print('hi')
btn = Button(tk, text='hi', command = tk.destroy)
btn.pack()
tk.mainloop()
but this doesn't:
from tkinter import*
tk = Tk()
tk.geometry('500x300')
def function():
print('hi')
btn = Button(tk, text='hi', command = lambda:[ function(),tk.destroy])
btn.pack()
tk.mainloop()
why?

Instead of using:
btn = Button(tk, text='hi', command = lambda:[ hello.hi(),tk.destroy])
use:
btn = Button(tk, text='hi', command = lambda:[hello.hi(),tk.destroy()])
and it should work.

Related

Tkinter crashes when clicking a button and remains pressed

I have a simple program with start and exit buttons. The start button makes a notification using win10toast, but the button remains visibly pressed down and the window becomes unresponsive. The exit button works fine before the start button is pressed. Here's my code:
from tkinter import *
from win10toast import ToastNotifier
root = Tk()
def exit_p():
exit()
def new():
hr.show_toast("New", "Alert")
return
#creates a label widget
myLabel1 = Label(root, text="Full Moon Notification!")
myLabel2 = Label(root, text="Here you can start and exit the program")
button1 = Button(root, text="Start",padx=50,command=new).grid(row=3,column=0)
button2 = Button(root, text="Exit", padx=50,command=exit_p).grid(row=4,column=0)
#puts the widget on the screen
myLabel1.grid(row=0,column=0)
myLabel2.grid(row=1,column=0)
#loop to keep program running
root.mainloop()
The issue is likely because hr.show_toast("New", "Alert") blocks.
The win10toast library conveniently provides an option threaded=True, so just change that code to
hr.show_toast("New", "Alert", threaded=True)
should make it work.

Close button tkinter after pressing button?

I created a button that works perfectly (not entire code here) but I want that once you press the 'Save' button, the window disappear. Someone knows how to do it?
root2 = tk.Tk()
root2.geometry('200x100')
save_button = tk.Button(root2)
save_button.configure(text='Save', command=lambda: ask_parameter(ents1))
save_button.pack()
root2.mainloop()
Based on the extremely limited snippet of code in your question: I would suggest it doing by defining a function to call that does something like this:
import tkinter as tk
def ask_and_close(root, ents):
ask_parameter(ents)
root.destroy()
ents1 = "something"
root2 = tk.Tk()
root2.geometry('200x100')
save_button = tk.Button(root2)
save_button.configure(text='Save', command=lambda: ask_and_close(root2, ents1))
save_button.pack()
root2.mainloop()
Note: If you're creating multiple windows, I wouild suggest using tk.Toplevel() instead of calling tk.TK() more than once.
Just use the master.quit() method!
Example Code:
from tkinter import *
class Test:
def __init__(self):
self.master = Tk()
self.button = Button(self.master, text="Push me!", command=self.closeScreen)
self.button.pack()
def closeScreen(self):
# In your case, you need "root2.quit"
self.master.quit()
test = Test()
mainloop()
I would suggest using destroy() method as used here https://docs.python.org/3.8/library/tkinter.html#a-simple-hello-world-program.
One of the easy ways to invoke the destroy method in your code is this;
def ask_parameter_and_destroy(ents1):
ask_parameter(ents1)
root2.destroy()
root2 = tk.Tk()
root2.geometry('200x100')
save_button = tk.Button(root2)
save_button.configure(text='Save', command=lambda: ask_parameter_and_destroy(ents1))
save_button.pack()
root2.mainloop()
You can read about differences between destroy() and previously proposed quit() methods on the following page: What is the difference between root.destroy() and root.quit()?.
If your goal is to create a dialog for saving a file, you might be interested in tkinter.filedialog library, which has ready made dialog boxes for handling file saving.

How do I redirect output of a script to a tkinter window?

I am trying to click a tkinter button to open up a new tkinter window to execute a script within it all the way up to the end with a scroll bar if necessary. However, I have only succeeded this far in getting it to run in multitude of ways in a linux window and not within a tkinter window. Can someone help me with redirecting the output of this script into the toplevel window?
self.button_run = Button(self, text="RUN", width=16, command=self.callpy)
self.button_run.grid(row=25, column=0, columnspan=2, sticky=(W + E + N + S))
def run_robbot(self):
new = Toplevel(self)
new.geometry('500x200')
label = Message(new, textvariable=self.callpy, relief=RAISED)
label.pack()
def callpy(self):
pyprog = 'check_asim.robot'
call(['robot', pyprog])
In the snippet above, if I pass callpy to command in Button it runs the robot script in a linux window. If I replace it to call run_robbot which is what I want and expect, it just pops up a new window with a Message Box without running the same script passed to textvariable. I have tried Enter in place of Message Box as well.
I want callpy to be executed in Toplevel tkinter window at the click of the button. How do I do it? Any tkinter operator is fine as long as it confines to the tkinter window.
If you want to capture the output of the command, you should use subprocess.run(cmd,capture_output=True) instead. Below is an sample code:
import subprocess
from tkinter import *
class App(Tk):
def __init__(self):
Tk.__init__(self)
Button(self, text='Run', command=self.run_robot).pack()
def run_robot(self):
win = Toplevel(self)
win.wm_attributes('-topmost', True)
output = Text(win, width=80, height=20)
output.pack()
output.insert(END, 'Running ....')
output.update()
result = self.callpy()
output.delete(1.0, END)
output.insert(END, result)
def callpy(self):
pyprog = 'check_asim.robot'
return subprocess.run(['robot', pyprog], capture_output=True).stdout
App().mainloop()

How do I make a button that closes one tkinter window and opens another?

When I make a button that closes the current window and opens another, the current window doesn't close.
from tkinter import *
root = Tk()
def new_window():
root.quit()
new_window = Tk()
new_window.mainloop()
Button(root, text="Create new window", command=new_window).pack()
root.mainloop()
(This isn't my program, it's just an example)
You should be able to do it like this:
import tkinter as tk
root = tk.Tk()
def new_window():
root = tk.Tk()
test = tk.Button(root, text="Create new window", command= lambda:[root.destroy(), new_window()]).pack()
root.mainloop()
test = tk.Button(root, text="Create new window", command= lambda:[root.destroy(), new_window()]).pack()
root.mainloop()
This will literally keep opening the exact same window with a button. The lambda allows you to call multiple functions. By calling .destroy() on your root window, it destroys your window, but doesn’t stop the program. Then you create a new root window with your function.
You can use this technique on your actual script.

No input possible after tk

If have this piece of code:
import Tkinter as tk
import tkFileDialog
menu = tk.Tk()
res = tkFileDialog.askopenfilename() # un-/comment this line
label = tk.Label(None, text="abc")
label.grid(row=0, column=0, sticky=tk.W)
entry = tk.Entry(None)
entry.grid(row=0, column=1, sticky=tk.EW)
res = menu.mainloop()
Note: the askopenfilename is just a dummy input. So Just close it to get to the (now blocked) main window of TK.
When I comment the askopenfilename everything works fine. But with the it, I can not enter data in the entry.
This only happens with Windoze environments. The askopenfilename seems to steal the focus for the main TK window. After clicking a totally different window and back again in the TK window, input is possible.
I've seen reports of this before, I think it's a known bug on windows. You need to let mainloop start before you open a dialog.
If you want the dialog to appear when the app first starts up you can use after or after_idle to have it run after mainloop starts up.
For example:
menu = tk.Tk()
...
def on_startup():
res = tkFileDialog.askopenfilename()
menu.after_idle(on_startup)
menu.mainloop()
If you don't want any other GUI code to execute until after the dialog, move all your code except for the creation of the root window and call to mainloop into on_startup or some other function.
For example:
def main(filename):
label = tk.Label(None, text="abc")
label.grid(row=0, column=0, sticky=tk.W)
entry = tk.Entry(None)
entry.grid(row=0, column=1, sticky=tk.EW)
def on_startup():
res = tkFileDialog.askopenfilename()
main(filename)
root = Tk()
root.after_idle(on_startup)
askopenfilenamehas it's own event loop. The programm stops, until you selected a filename, and continues afterwards.

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