问题
Based on the example from Dynamically changing scrollregion of a canvas in Tkinter, I am trying to implement a Frame where you can add and delete entries in a scrollable Frame using tkinter. My Problem is that the Frame holding items does not resize after deleting entries. When adding entries, it resizes correctly. I call update_layout() in both cases:
from tkinter import *
class ScrollableContainer(Frame):
"""A scrollable container that can contain a number of messages"""
def __init__(self, master, **kwargs):
Frame.__init__(self, master, **kwargs) #holds canvas & scrollbars
# configure row and col to take additional space if there is some
self.grid_rowconfigure(0, weight=1)
self.grid_columnconfigure(0, weight=1)
# create canvas
self.canv = Canvas(self, bd=0, highlightthickness=0)
# create scrollbars
self.hScroll = Scrollbar(self, orient='horizontal',
command=self.canv.xview)
self.hScroll.grid(row=1, column=0, sticky='we')
self.vScroll = Scrollbar(self, orient='vertical',
command=self.canv.yview)
self.vScroll.grid(row=0, column=1, sticky='ns')
# set postiotion of canvas in (self-)Frame
self.canv.grid(row=0, column=0, sticky='nsew')
self.canv.configure(xscrollcommand=self.hScroll.set,
yscrollcommand=self.vScroll.set)
# create frame to hold messages in canvas
self.frm = Frame(self.canv, bd=2, bg='gray') #holds messages
self.frm.grid_columnconfigure(0, weight=1)
# create empty tkinter widget (self.frm) on the canvas
self.canv.create_window(0, 0, window=self.frm, anchor='nw', tags='inner')
# update layout
self.update_layout()
# on change of size or location this event is fired. The event provides new width an height to callback function on_configure
self.canv.bind('<Configure>', self.on_configure)
self.widget_list = []
# update and resize layout
def update_layout(self):
print('update')
self.frm.update_idletasks()
self.canv.configure(scrollregion=self.canv.bbox('all'))
self.size = self.frm.grid_size()
# resize canvas and scroll region depending on content
def on_configure(self, event):
print('on_configure')
# get new size of canvas
w,h = event.width, event.height
# get size of frm required to display all content
natural = self.frm.winfo_reqwidth()
self.canv.itemconfigure('inner', width= w if w>natural else natural)
self.canv.configure(scrollregion=self.canv.bbox('all'))
# add new entry and update layout
def add_message(self, text):
print('add message')
# create var to represent states
int_var = IntVar()
cb = Checkbutton(self.frm, text=text, variable=int_var)
cb.grid(row=self.size[1], column=0, padx=1, pady=1, sticky='we')
self.widget_list.append(cb)
self.update_layout()
# delete all messages
def del_message(self):
print('del message')
for it in self.widget_list:
it.destroy()
self.update_layout()
root = Tk()
root.grid_rowconfigure(0, weight=1)
root.grid_columnconfigure(0, weight=1)
sc = ScrollableContainer(root, bd=2, bg='black')
sc.grid(row=0, column=0, sticky='nsew')
def new_message():
test = 'Something Profane'
sc.add_message(test)
def del_message():
sc.del_message()
b = Button(root, text='New Message', command=new_message)
b.grid(row=1, column=0, sticky='we')
del_b = Button(root, text='Del Message', command=del_message)
del_b.grid(row=2, column=0, sticky='we')
root.mainloop()
回答1:
I was working on something similar so I took my code and merged it with yours for the answer.
Here is a scrollingFrame class that will add scrollbars and remove them whenever the box is resized. Then there is a second class for your message list that will tell the scrollingFrame to readjust itself as necessary whenever items are added/deleted.
class scrollingFrame(Frame):
def __init__(self, parentObject, background):
Frame.__init__(self, parentObject, background = background)
self.canvas = Canvas(self, borderwidth=0, background = background, highlightthickness=0)
self.frame = Frame(self.canvas, background = background)
self.vsb = Scrollbar(self, orient="vertical", command=self.canvas.yview, background=background)
self.canvas.configure(yscrollcommand=self.vsb.set)
self.vsb.grid(row=0, column=1, sticky=N+S)
self.hsb = Scrollbar(self, orient="horizontal", command=self.canvas.xview, background=background)
self.canvas.configure(xscrollcommand=self.hsb.set)
self.hsb.grid(row=1, column=0, sticky=E+W)
self.canvas.grid(row=0, column=0, sticky=N+S+E+W)
self.window = self.canvas.create_window(0,0, window=self.frame, anchor="nw", tags="self.frame")
self.grid_columnconfigure(0, weight=1)
self.grid_rowconfigure(0, weight=1)
self.frame.bind("<Configure>", self.onFrameConfigure)
self.canvas.bind("<Configure>", self.onCanvasConfigure)
def onFrameConfigure(self, event):
#Reset the scroll region to encompass the inner frame
self.canvas.configure(scrollregion=self.canvas.bbox("all"))
def onCanvasConfigure(self, event):
#Resize the inner frame to match the canvas
minWidth = self.frame.winfo_reqwidth()
minHeight = self.frame.winfo_reqheight()
if self.winfo_width() >= minWidth:
newWidth = self.winfo_width()
#Hide the scrollbar when not needed
self.hsb.grid_remove()
else:
newWidth = minWidth
#Show the scrollbar when needed
self.hsb.grid()
if self.winfo_height() >= minHeight:
newHeight = self.winfo_height()
#Hide the scrollbar when not needed
self.vsb.grid_remove()
else:
newHeight = minHeight
#Show the scrollbar when needed
self.vsb.grid()
self.canvas.itemconfig(self.window, width=newWidth, height=newHeight)
class messageList(object):
def __init__(self, scrollFrame, innerFrame):
self.widget_list = []
self.innerFrame = innerFrame
self.scrollFrame = scrollFrame
# Keep a dummy empty row if the list is empty
self.placeholder = Label(self.innerFrame, text=" ")
self.placeholder.grid(row=0, column=0)
# add new entry and update layout
def add_message(self, text):
print('add message')
self.placeholder.grid_remove()
# create var to represent states
int_var = IntVar()
cb = Checkbutton(self.innerFrame, text=text, variable=int_var)
cb.grid(row=self.innerFrame.grid_size()[1], column=0, padx=1, pady=1, sticky='we')
self.widget_list.append(cb)
self.innerFrame.update_idletasks()
self.scrollFrame.onCanvasConfigure(None)
# delete all messages
def del_message(self):
print('del message')
for it in self.widget_list:
it.destroy()
self.placeholder.grid()
self.innerFrame.update_idletasks()
self.scrollFrame.onCanvasConfigure(None)
deviceBkgColor = "#FFFFFF"
root = Tk() # Makes the window
root.grid_rowconfigure(0, weight=1)
root.grid_columnconfigure(0, weight=1)
root.wm_title("Title") # Makes the title that will appear in the top left
root.config(background = deviceBkgColor)
myFrame = scrollingFrame(root, background = deviceBkgColor)
myFrame.grid(row=0, column=0, sticky=N+S+E+W)
msgList = messageList(myFrame, myFrame.frame)
def new_message():
test = 'Something Profane'
msgList.add_message(test)
def del_message():
msgList.del_message()
b = Button(root, text='New Message', command=new_message)
b.grid(row=1, column=0, sticky='we')
del_b = Button(root, text='Del Message', command=del_message)
del_b.grid(row=2, column=0, sticky='we')
root.mainloop() #start monitoring and updating the GUI
来源：https://stackoverflow.com/questions/32063868/scrollable-frame-does-not-resize-properly-using-tkinter-in-python