Python Tkinter button not appearing? - python

I'm new to tkinter and I have this code in python:
#import the tkinter module
from tkinter import *
import tkinter
calc_window = tkinter.Tk()
calc_window.title('Calculator Program')
button_1 = tkinter.Button(text = '1', width = '30', height = '20')
button_1 = '1'
calc_window.mainloop()
But when I run it, the button doesn't appear. Does anyone know why? Thank you!

Getting a widget to appear requires two steps: you must create the widget, and you must add it to a layout. That means you need to use one of the geometry managers pack, place or grid to position it somewhere in its container.
For example, here is one way to get your code to work:
button_1 = tkinter.Button(text = '1', width = '30', height = '20')
button_1.pack(side="top")
The choice of grid or pack is up to you. If you're laying things out in rows and columns, grid makes sense because you can specify rows and columns when you call grid. If you are aligning things left-to-right or top-to-bottom, pack is a little simpler and designed for such a purpose.
Note: place is rarely used because it is designed for precise control, which means you must manually calculate x and y coordinates, and widget widths and heights. It is tedious, and usually results in widgets that don't respond well to changes in the main window (such as when a user resizes). You also end up with code that is somewhat inflexible.
An important thing to know is that you can use both pack and grid together in the same program, but you cannot use both on different widgets that have the same parent.

from tkinter import *
import tkinter
calc_window = tkinter.Tk()
calc_window.title('Calculator Program')
frame = Frame(calc_window )
frame.pack()
button_1 = tkinter.Button(frame,text = '1', width = '30', height = '20')
button_1.pack(side=LEFT)
calc_window.mainloop()
try adding the button using pack(). i donno why u tried to assign button_1 = '1' in your code
a neat example:
from Tkinter import *
class App:
def __init__(self, master):
frame = Frame(master)
frame.pack()
self.button = Button(
frame, text="QUIT", fg="red", command=frame.quit
)
self.button.pack(side=LEFT)
self.hi_there = Button(frame, text="Hello", command=self.say_hi)
self.hi_there.pack(side=LEFT)
def say_hi(self):
print "hi there, everyone!"
root = Tk()
app = App(root)
root.mainloop()

You're not packing the button_1. The code is:
from tkinter import *
root = Tk()
root.title('Calculator Program')
button_1 = Button(root, text='1', width='30', height='20')
button_1.pack()
root.mainloop()
It's simple!
Hope this helps!

from tkinter import *
calc_window = Tk()
calc_window.title('Calculator Program')
button_1 = Button(text = '1')
button_1.place(x=0,y=0,width = 30, height = 20)
calc_window.mainloop()

Related

tkinter get widget that event got called by

Minimal reproducable Example
from tkinter import *
def test(event):
print(event.widget)
window = Tk()
window.geometry("600x600")
window.bind("<Motion>", test)
frame = Frame(window, bg="red", width=200, height=200)
frame.pack()
frame.bind("<Motion>", test)
window.mainloop()
I want to call the function "test" from different widgets when i move over them. Instead of that, when i hover over the frame, both the window and the frame print that im hovering over the frame, which is not the behaviour i need. Can someone help me achieve the right behaviour?
I think your confusion is in the moment of interpreting when the mouse pointer entered the widget or left the widget. Instead of Motion let's use for example Leave and Enter events to better understand what happens.
I have taken the liberty of including some labels that show which widget we enter and left at each moment.
from tkinter import *
def test_enter(event):
enter.set(event.widget)
def test_left(event):
left.set(event.widget)
window = Tk()
window.geometry("300x300")
window.bind("<Enter>", test_enter)
window.bind("<Leave>", test_left)
frame = Frame(window, bg="red", width=200, height=200)
frame.pack()
frame.bind("<Enter>", test_enter)
frame.bind("<Leave>", test_left)
label1 = Label(frame, text="Enter")
label1.place(relx=0.1, rely=0.4, x= 0.2, y=0.2)
enter = StringVar()
label_enter = Label(frame, textvariable=enter)
label_enter.place(relx=0.3, rely=0.4, x= 0.6, y=0.2)
label2 = Label(frame, text="Leave")
label2.place(relx=0.1, rely=0.6, x= 0.2, y=0.2)
left = StringVar()
label_left = Label(frame, textvariable=left)
label_left.place(relx=0.3, rely=0.6, x= 0.6, y=0.2)
window.mainloop()
Remember that the Frame is inside the Window. I mean that when you enter the Window you have not left root Window, you will continue to be in Window. Or if you enter inside a Label you have not left the Frame.
You could use lambda to pass the widget when the function is run
def test(event, widget):
print(widget)
window = Tk()
window.geometry("600x600")
window.bind("<Motion>", test)
frame = Frame(window, bg="red", width=200, height=200)
frame.pack()
frame.bind("<Motion>", lambda: test(frame))
window.mainloop()
You just need to change two lines
def test(event, widget):
print(widget)
and
frame.bind("<Motion>", lambda: test(frame))

Why isn't the label animation working till the last value of the loop?

I am new to python and I have been learning tkinter recently. So I thought with myself that using the grid_forget() function I can remove a widget and redefine it. I thought of this animation that changes the padding of a label so it would create space (kind of like moving the label but not exactly). However, the animation does not work at all. The program freezes until the label reaches the last value of the padding. How can I fix this? Or is there a better way to animate a label moving in the screen?
Here is my code:
from tkinter import *
import time
root = Tk()
lbl = Label(root, text='------')
lbl.grid(row=0, column=0)
def animation():
padding = 0
while padding < 31:
lbl.grid_forget()
padding += 1
lbl.grid(row=0, column=0, padx=padding)
time.sleep(0.2)
# alternative: root.after(200, lambda: lbl.grid(row=0, column=0, padx=padding))
btn = Button(root, text='Animate', command=animation)
btn.grid(row=1, column=1)
root.mainloop()
You need to update the screen for changes to be shown.
Here is a working version using the .update() method:
from tkinter import *
import time
root = Tk()
lbl = Label(root, text='------')
lbl.grid(row=0, column=0)
def animation():
padding = 0
while padding < 31:
lbl.grid_forget()
padding += 1
lbl.grid(row=0, column=0, padx=padding)
root.update()
time.sleep(0.2)
# alternative: root.after(200, lambda: lbl.grid(row=0, column=0, padx=padding))
btn = Button(root, text='Animate', command=animation)
btn.grid(row=1, column=1)
root.mainloop()
Here is a way I also use to animate stuff on the screen, I am not able to understand what you were trying to achieve with your code snippet above, I tried making some changes to it but I feel this way is much better and let's you get more control of your window.
This uses the widely used Canvas widget in the tkinter library.
The Canvas is a general purpose widget, You can use it for a lot of things. Visit the hyper link for more clarity
Here is a short example of how you would create text on the screen.
from tkinter import *
root = Tk()
root.title("My animation")
c = Canvas(root)
x = 20
y = 20 #Instead of using row and column, you simply use x and y co-ordinates
#We will use these co-ordinates to show where the text is in the starting
my_text = c.create_text(x,y,text = '-----')
c.pack()
# This is all you need to create this text on your screen!
root.mainloop()
The idea is that you put your canvas up on your window , and then place whatever you want on it.
There are a lot more attributes that you can add to make your text look even better. Here is an in-depth tutorial on it.
Now that we have made your text widget, It is now time to move it around. Let us move it to 90,20 From our initial position which is 20,20
Here is how we will do it. If we simply move to text object to 90,90, We won't see any animations, it will just directly have it there. So what we will do is first create it at 21,20. Then 22,20. And so on...
We do this really fast till we reach 90,20
This looks like we are moving the text
from tkinter import *
import time
root = Tk()
root.title("My animation")
c = Canvas(root)
x = 20
y = 20 #Instead of using row and column, you simply use x and y co-ordinates
#We will use these co-ordinates to show where the text is in the starting
my_text = c.create_text(x,y,text = 'weee')
c.pack()
def animation():
y = 0.1
x = 0
for _ in range(1000):
c.move(my_text,x,y)
root.update()
anlabel = Button(root,text = 'Animate!',command = animation).pack()
root.mainloop()
This is not only applicable to text, but everything (like other images)that is there on the canvas. The canvas also has Events which will let you use mouse-clicks and other keys on the computer too.
I have made some changes from the previous code, But it is executable and you can try it for yourself to see how it works. increasing the value in time.sleep() makes the animation slower, the lesser the value, the faster.
Are you sure you aren't trying to do something more like the below example? Animating the padding on one of your widgets is going to screw up the rest of your display.
from tkinter import *
import time
root = Tk()
lbl = Label(root, text='')
lbl.grid(row=0, column=0)
def animation(step=12):
step = 12 if step < 0 else step
lbl['text'] = ' ------ '[step:step+6]
root.after(200, lambda: animation(step-1))
Button(root, text='Animate', command=animation).grid(row=1, column=0, sticky='w')
root.mainloop()

Why is Tkinter not displaying Button?

import Tkinter as ass
root = ass.Tk()
frame = ass.Frame(root)
button1 = ass.Button(frame, command=button1(), text='Kushagra', width=50, height=40)
button1.pack(side=ass.LEFT)
root.mainloop()
button1() is a function I made which i don't think is relevant. After I run this all I get is a blank window. How do I fix this?
You didn't pack the frame widget after creating the frame. The below is the edited code
import tkinter as ass
root = ass.Tk()
frame = ass.Frame(root)
frame.pack()
button1 = ass.Button(frame, text="QUIT")
button1.pack(side=ass.LEFT)
root.mainloop()
You have to pack the frame if you want it to be displayed. This will let the button to be shown but the function button1() won't work as you want because it would be called when it is given to the Button as a command, As you have used parenthesis () after giving it to the button as a command. You just need to remove those parentheses.
Like this:
import tkinter as ass
def button1():
return
root = ass.Tk()
frame = ass.Frame(root)
frame.pack()
button1 = ass.Button(frame, command=button1, text='Kushagra', width=50, height=40)
button1.pack(side=ass.LEFT)
root.mainloop()
And if you need to pass arguments to any function then you should use lambda before giving it as a command to any Button.
Like this:
import tkinter as ass
def test(a):
print(a)
root = ass.Tk()
frame = ass.Frame(root)
frame.pack()
button1 = ass.Button(frame, command=lambda: test(1), text='Kushagra', width=50, height=40)
button1.pack(side=ass.LEFT)
root.mainloop()

tkinter python entry height

I'm making a simple app just to practice python in which I want to write text as if it were Notepad. However, I can't make my entry bigger. I'm using tkinter for this. Does anybody know how to make the height of an entry bigger?
I tried something like this:
f = Frame()
f.pack()
e = Entry(f,textvariable=1,height=20)
e.pack()
I know this doesn't work because there isn't a property of "height". However, I see that there is a width property.
It sounds like you are looking for tkinter.Text, which allows you to adjust both the height and width of the widget. Below is a simple script to demonstrate:
from tkinter import Text, Tk
r = Tk()
r.geometry("400x400")
t = Text(r, height=20, width=40)
t.pack()
r.mainloop()
Another way would be to increase the internal padding by adding this in the pack method:
...
e = Entry(f,textvariable=1,height=20)
e.pack(ipady=3)
...
for instance. This worked for me for an 'Entry' and it also works with .grid()
Actually it's very easy. You don't need to set height in Entry(), but in place().
for example:
from tkinter import Entry, Tk
window = Tk()
t = Entry(window)
t.place(width=150,height=50)
window.mainloop()
from tkinter import *
root=Tk()
url = Label(root,text="Enter Url")
url.grid(row=0,padx=10,pady=10)
entry_url = Entry(root,width="50")
entry_url.grid(row=0,column=1,padx=5,pady=10,ipady=3)
root.geometry("600x300+150+150")
root.mainloop()
learn more follow this github
output image this is output of above code
You can also change it by changing the font size :
Entry(
root,
font=("default", 40 or 20 whatever )
)
To change an entry widget's size, you have to change it's font to a larger font.
Here is my code:
import tkinter as tk
large_font = ('Verdana',30)
small_font = ('Verdana',10)
root = tk.Tk()
entry1Var = tk.StringVar(value='Large Font!')
entry1 = tk.Entry(root,textvariable=entry1Var,font=large_font)
entry1.pack()
entry2Var = tk.StringVar(value='Small Font!')
entry2 = tk.Entry(root,textvariable=entry2Var,font=small_font)
entry2.pack()
root.mainloop()
You can change the height of the entry widget.
To do so you can write:
entry_box.place(height=40, width=100)
Change the value according to your needs!
IT WORKS !
By using the .place(width= , height= ) method, you can adjust the size of the entry. Another Method is to change the font of the text, but that limits your ability to change the font.
.place() method:
textbox.place(width= (Your desired width) ,height= (Your desired height))
Font Method:
textbox = Entry(root, font=("default", (Your font size))
Hope this helps!

How to control the tkinter combobox selection highlighting

I wrote a small farad converter to learn GUI programming. It works great, looks fine-ish. The only problem is I can't seem to figure out how to control this strange highlighting that comes up on my ttk.Combobox selections. I did use a ttk.Style(), but it only changed the colors of the ttk.Combobox background, entries, etc. I also tried changing openbox/gtk themes.
I'm talking about what's seen there on the text "microfarads (uF)".
It'd be fine, if it highlighted the entire box; but I'd rather have it gone completely.
How can I manipulate a ttk.Combobox's selection highlight?
# what the farad?
# thomas kirkpatrick (jtkiv)
from tkinter import *
from tkinter import ttk
# ze la programma.
def conversion(*args):
# this is the numerical value
inV = float(inValue.get())
# these two are the unit (farads, microfarads, etc.) values
inU = inUnitsValue.current()
outU = outUnitsValue.current()
# "mltplr" is multiplied times inValue (inV)
if inU == outU:
mltplr = 1
else:
mltplr = 10**((outU - inU)*3)
outValue.set(inV*mltplr)
# start of GUI code
root = Tk()
root.title("What the Farad?")
# frame
mainFrame = ttk.Frame(root, width="364", padding="4 4 8 8")
mainFrame.grid(column=0, row=0)
# input entry
inValue = StringVar()
inValueEntry = ttk.Entry(mainFrame, width="20", justify="right", textvariable=inValue)
inValueEntry.grid(column=1, row=1, sticky="W")
# input unit combobox
inUnitsValue = ttk.Combobox(mainFrame)
inUnitsValue['values'] = ('kilofarads (kF)', 'farads (F)', 'millifarads (mF)', 'microfarads (uF)', 'nanofarads (nF)', 'picofarads (pF)')
inUnitsValue.grid(column=2, row=1, sticky="e")
inUnitsValue.state(['readonly'])
inUnitsValue.bind('<<ComboboxSelected>>', conversion)
# result label
outValue = StringVar()
resultLabel = ttk.Label(mainFrame, textvariable=outValue)
resultLabel.grid(column=1, row=2, sticky="e")
# output unit combobox
outUnitsValue = ttk.Combobox(mainFrame)
outUnitsValue['values'] = ('kilofarads (kF)', 'farads (F)', 'millifarads (mF)', 'microfarads (uF)', 'nanofarads (nF)', 'picofarads (pF)')
outUnitsValue.grid(column=2, row=2, sticky="e")
outUnitsValue.state(['readonly'])
outUnitsValue.bind('<<ComboboxSelected>>', conversion)
# padding for widgets
for child in mainFrame.winfo_children(): child.grid_configure(padx=4, pady=4)
# focus
inValueEntry.focus()
# bind keys to convert (auto-update, no button)
root.bind('<KeyRelease>', conversion)
root.mainloop()
Could it be that with a readonly combobox the problem is not the selection but the relatively strong focus-indicator?
With this workarround you lose the ability to control your program by keyboard. To do it right you would have to change the style of the focus-highlighting.
from tkinter import *
from ttk import *
def defocus(event):
event.widget.master.focus_set()
root = Tk()
comboBox = Combobox(root, state="readonly", values=("a", "b", "c"))
comboBox.grid()
comboBox.set("a")
comboBox.bind("<FocusIn>", defocus)
mainloop()
You can use the Combobox's selection_clear() method to clear the selection whenever you want.
e.g
inUnitsValue.selection_clear()
Just refresh the selected value of the Combobox.
This will help for removing the highlight.
import tkinter.ttk
import tkinter
items = ["test1","test2","test3","test4"]
class TkCombobox(tkinter.ttk.Combobox):
def __init__(self, *arg, **kwarg):
super(TkCombobox, self).__init__(*arg, **kwarg)
self._strvar_ = tkinter.StringVar()
self._strvar_.set("")
self["textvariable"] = self._strvar_
self.bind("<<ComboboxSelected>>", self.highlight_clear)
def highlight_clear(self, event):
current = self._strvar_.get()
self.set("")
self.set(current)
master = tkinter.Tk();master.geometry("400x400")
c = TkCombobox(master, values=items, state="readonly")
c.pack()
master.mainloop()

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