How could I get a Frame with a scrollbar in Tkinte

问题:

I'd like to have a Frame, where the user could add as many textfields as needed by the application.

The application starts with a textfield, and a button below that textfield. When the user presses the button, a new text entry will be added below the first one ( this may be repeated countless times ). In the middle of the window, there will be a Text widget, used to display text :)

However, I noticed this in the documentation:

This widget is used to implement scrolled listboxes, canvases, and text fields.

Is there a way to use the Scrollbar with a Frame?

回答1:

If you can use Tix, there is the ScrolledWindow widget which has a window Frame and one or two Scrollbar widgets:

import Tix as tk

r= tk.Tk()
r.title("test scrolled window")
sw= tk.ScrolledWindow(r, scrollbar=tk.Y) # just the vertical scrollbar
sw.pack(fill=tk.BOTH, expand=1)
for i in xrange(10):
    e= tk.Entry(sw.window)
    e.pack()
r.mainloop()

Change the size of the root window. You will want to add code to the focus_get event of the Entry widgets to scroll the ScrolledWindow when tabbing through the keyboard.

Otherwise, you will have to use a Canvas widget (you can add Label, Entry and Text subwidgets) and write a lot more code yourself to implement your required functionality.

回答2:

The following is an example of auto hiding scrollbars that only works if you just use the grid geometry manager, taken from the effbot.org documentation:

from tkinter import *


class AutoScrollbar(Scrollbar):
    # A scrollbar that hides itself if it's not needed.
    # Only works if you use the grid geometry manager!
    def set(self, lo, hi):
        if float(lo) <= 0.0 and float(hi) >= 1.0:
            # grid_remove is currently missing from Tkinter!
            self.tk.call("grid", "remove", self)
        else:
            self.grid()
        Scrollbar.set(self, lo, hi)
    def pack(self, **kw):
        raise TclError("cannot use pack with this widget")
    def place(self, **kw):
        raise TclError("cannot use place with this widget")


# create scrolled canvas

root = Tk()

vscrollbar = AutoScrollbar(root)
vscrollbar.grid(row=0, column=1, sticky=N+S)
hscrollbar = AutoScrollbar(root, orient=HORIZONTAL)
hscrollbar.grid(row=1, column=0, sticky=E+W)

canvas = Canvas(root, yscrollcommand=vscrollbar.set, xscrollcommand=hscrollbar.set)
canvas.grid(row=0, column=0, sticky=N+S+E+W)

vscrollbar.config(command=canvas.yview)
hscrollbar.config(command=canvas.xview)

# make the canvas expandable
root.grid_rowconfigure(0, weight=1)
root.grid_columnconfigure(0, weight=1)

# create canvas contents
frame = Frame(canvas)
frame.rowconfigure(1, weight=1)
frame.columnconfigure(1, weight=1)

rows = 5
for i in range(1, rows):
    for j in range(1, 10):
        button = Button(frame, text="%d, %d" % (i,j))
        button.grid(row=i, column=j, sticky='news')

canvas.create_window(0, 0, anchor=NW, window=frame)
frame.update_idletasks()
canvas.config(scrollregion=canvas.bbox("all"))

root.mainloop()