I want to create a custom widget in tkinter such that when instantiated, displays a label and an entry box. Example I created a class named entry and call as.. entry ('name', master ) and this would display a label with text as main along side an entry box. I have succeeded in doing that but my problem is with the geometry managers. they all seem to mess up everything
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2You need to post some code with the actual error, it's very difficult to help with just the information you've givenEd Smith– Ed Smith2015-05-27 17:39:22 +00:00Commented May 27, 2015 at 17:39
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3 Answers
Your widget should subclass Frame. Within the frame you can use any geometry manager you want without affecting any other code. It's important that the widget class does not call grid, pack or place on itself -- that's the job of the function that creates the widget. Every widget, or function that creates a widget, should only ever worry about laying out its children.
Here's an example that creates a couple of different custom widgets. Each uses a different geometry manager to illustrate that they don't interfere with each other:
try:
# python 3.x
import tkinter as tk
except ImportError:
# python 2.x
import Tkinter as tk
class CustomWidget(tk.Frame):
def __init__(self, parent, label, default=""):
tk.Frame.__init__(self, parent)
self.label = tk.Label(self, text=label, anchor="w")
self.entry = tk.Entry(self)
self.entry.insert(0, default)
self.label.pack(side="top", fill="x")
self.entry.pack(side="bottom", fill="x", padx=4)
def get(self):
return self.entry.get()
class Example(tk.Frame):
def __init__(self, parent):
tk.Frame.__init__(self, parent)
self.label = tk.Label(self)
self.e1 = CustomWidget(self, "First Name:", "Inigo")
self.e2 = CustomWidget(self, "Last Name:", "Montoya")
self.submitButton = tk.Button(self, text="Submit", command=self.submit)
self.e1.grid(row=0, column=0, sticky="ew")
self.e2.grid(row=1, column=0, sticky="ew")
self.label.grid(row=2, column=0, sticky="ew")
self.submitButton.grid(row=4, column=0)
self.grid_columnconfigure(0, weight=1)
self.grid_rowconfigure(2, weight=1)
def submit(self):
first = self.e1.get()
last = self.e2.get()
self.label.configure(text="Hello, %s %s" % (first, last))
if __name__ == "__main__":
root = tk.Tk()
Example(root).place(x=0, y=0, relwidth=1, relheight=1)
root.mainloop()
9 Comments
cxↄ
Can you tell how did you learn/got this way of creating a custom widget?
Bryan Oakley
@Yeheshuah: I first started using tk with the Tcl language back in the early 1990's, and started learning python and tkinter more than a decade ago. I didn't so much learn how to write code this way, it was more of a natural progression based on many years of experience.
cxↄ
Maybe you know answer to Is it possible to set trasparent background of Canvas?
Delrius Euphoria
@Yeheshuah I think if the image is a png and has mode RGBA then an image on canvas created with
canvas.create_image(..) would make the transparency come alive. |
I agree with Mr. Oakley. You should subclass frame to do your job. The simplest way to do what you want is to create a module with the following code:
# AnnotatedEntry.py
def AnnotatedEntry(master, name="An annoted entry box"):
'''
As a little extra, name is a keyword-argument, which defaults to "An annotated
entry box."
'''
import tkinter as tk
overlord = tk.Frame(master, height=5, width=40)
labeller = tk.Label(overlord, text=name, font="Times 14 bold")
labeller.grid(sticky='new')
inputter = tk.Entry(overlord, font="Times 14 bold")
inputter.grid(sticky='sew', pady=(10,0))
return overlord
This would be used as follows:
# Main program
import tkinter
import AnnotatedEntry
root = tkinter.Tk()
hold = AnnotatedEntry.AnnotatedEntry(root, name="Hello, world!")
hold.grid()
I hereby affirm, on my Scout Honor, that this code has been fully tested, and is guaranteed to work in Python 3.7.4. That being said, there is currently no method for returning the data contained in the Entry; you will have to work that out for yourself.
Comments
Based on @Bryan Oakley answer, I do have some modification. I know it's out of topic somehow. This is how to return a value from the widget and it only allows integer up to some number of digits that the user must entered.
#create a global value
global tbVal
tbVal = 0
class CustomWidget(tk.Frame):
def __init__(self, parent, nDigits):
tk.Frame.__init__(self, parent)
self.entry = tk.Entry(self)
self.entry.pack(side="bottom", fill="x", padx=4)
self.entry.configure(validate='all',validatecommand=windows.register(self.sbValidate),'%P','%W',nDigits))
def get(self):
return self.entry.get()
def sbValidate(self, userInput, widget, nDigits):
global tbVal
tbVal = userInput
if userInput == '':
return True
if '.' in userInput or ' ' in userInput:
return False
n = len(userInput)
if n > int(nDigits):
return False
try:
val = int(float(userInput))
except ValueError:
return False
return val
class Example(tk.Frame):
def __init__(self, parent, nDigitsLimit):
tk.Frame.__init__(self, parent)
self.e1 = CustomWidget(self, nDigitsLimit)
self.e1.grid(row=0, column=0, sticky="ew")
self.grid_columnconfigure(0, weight=1)
self.grid_rowconfigure(2, weight=1)
def btnStartClick():
print(tbVal)
nDigitsLimit = 8
tbTest = ttk.Entry(Example(windows, nDigitsLimit).place(x=20, y=20, relwidth=0.25, relheight=0.05))
btnStart = tk.Button(frame, text='Start', command=btnStartClick)
btnStart.place(relx=0.50, rely=0.50)
