因此，我有一个继承自 frame 并包含 Canvas 和滚动条的自定义小部件，以及一个也继承自 frame 的自定义小部件，我想将其动态添加到 Canvas ，并根据需要调整 scrollregion 的大小。这是我的代码:
class MessageItem(Frame):
"""A message to be contained inside a scrollableContainer"""
def __init__(self, message, **kwds):
Frame.__init__(self, **kwds)
self.text = Label(self, text = message)
self.text.grid(column = 0, row = 0, sticky = N+S+E+W)
class scrollableContainer(Frame):
"""A scrollable container that can contain a number of messages"""
def initContents(self):
"""Initializes a scrollbar, and a canvas that will contain all the items"""
#the canvas that will contain all our items
self.canv = Canvas(self)
self.canv.grid(column = 0, row = 0, sticky = N+S+W)
#force Tkinter to draw the canvas
self.canv.update_idletasks()
#use the values from the canvas being drawn to determine the size of the scroll region
#note that currently, since the canvas contains nothing, the scroll region will be the same as
#the size of the canvas
geometry = self.canv.winfo_geometry()
xsize, ysize, xpos, ypos = parse_geometry_string(geometry)
self.canv['scrollregion'] = (0, 0, xsize, ysize)
#the scrollbar for that canvas
self.vscroll = Scrollbar(self, orient = VERTICAL, command = self.canv.yview )
self.vscroll.grid(column = 1, row = 0, sticky = N+S+E)
self.canv["yscrollcommand"] = self.vscroll.set
def __init__(self, **kwds):
Frame.__init__(self, **kwds)
#initialize the widget's contents
self.grid(sticky = N+S+E+W)
self.pack()
self.initContents()
#initialize the list of contents so we can append to it
self.contents = []
def addMessage(self, message):
#Add the message to the list of contents
self.contents.append(MessageItem(message))
#Add the message to the grid
self.contents[(len(self.contents) - 1)].grid(column = 0, row = (len(self.contents) - 1))
#set the new scrollable region for the canvas
scrollregionlist = self.canv['scrollregion'].split()
oldRegion = int(scrollregionlist[3])
newRegion = oldRegion + parse_geometry_string(self.contents[
(len(self.contents) - 1)].winfo_geometry())[3]
self.canv['scrollregion'] = (int(scrollregionlist[0]), int(scrollregionlist[1]),
int(scrollregionlist[2]), newRegion)
我遇到的问题是 self.canv['scrollregion'] 似乎在 init 之外消失了。在 addMessage 方法中，在行中:
scrollregionlist = self.canv['scrollregion'].split()
self.canv 上的 scrollregion 属性返回一个空字符串，我可以通过放置一个来验证
print self.canv['scrollregion']
在那行之前
请您参考如下方法:
您确定文本小部件在这里不够用吗？
无论如何，
from Tkinter import *
class MessageItem(Frame):
"""A message to be contained inside a scrollableContainer"""
def __init__(self, master, message, **kwds):
Frame.__init__(self, master, **kwds)
self.grid_rowconfigure(0, weight=1)
self.grid_columnconfigure(0, weight=1)
self.text = Label(self, text=message, anchor='w', bg='gold')
self.text.grid(row=0, column=0, sticky='nsew')
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
self.grid_rowconfigure(0, weight=1)
self.grid_columnconfigure(0, weight=1)
self.canv = Canvas(self, bd=0, highlightthickness=0)
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')
self.canv.grid(row=0, column=0, sticky='nsew')
self.canv.configure(xscrollcommand=self.hScroll.set,
yscrollcommand=self.vScroll.set)
self.frm = Frame(self.canv, bd=2, bg='green') #holds messages
self.frm.grid_columnconfigure(0, weight=1)
self.canv.create_window(0, 0, window=self.frm, anchor='nw', tags='inner')
self.messages = []
for i in range(20):
m = MessageItem(self.frm, 'Something Profound', bd=2, bg='black')
m.grid(row=i, column=0, sticky='nsew', padx=2, pady=2)
self.messages.append(m)
self.update_layout()
self.canv.bind('<Configure>', self.on_configure)
def update_layout(self):
self.frm.update_idletasks()
self.canv.configure(scrollregion=self.canv.bbox('all'))
self.canv.yview('moveto','1.0')
self.size = self.frm.grid_size()
def on_configure(self, event):
w,h = event.width, event.height
natural = self.frm.winfo_reqwidth()
self.canv.itemconfigure('inner', width= w if w>natural else natural)
self.canv.configure(scrollregion=self.canv.bbox('all'))
def add_message(self, message):
m = MessageItem(self.frm, message, bd=2, bg='red')
m.grid(row=self.size[1], column=0, padx=2, pady=2, sticky='we')
self.messages.append(m)
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)
b = Button(root, text='New Message', command=new_message)
b.grid(row=1, column=0, sticky='we')
root.mainloop()
