同时滚动多个Tkinter列表框

Question

我有多个Tkinter的列表框，它们通过一个滚动条一起滚动，但我还希望它们在用鼠标滚轮滚动时也能一起滚动。

该怎么做呢？

我现在的代码是基于这里讨论的最后一个模式：http://effbot.org/tkinterbook/listbox.htm。当只使用滚动条时，它工作得很好，但当用鼠标滚轮时，列表框却是独立滚动的。

Answer 1

这是我目前的解决方案，写成了一个独立的函数（是的，它应该是一个对象）。

功能/要求：

• 可以处理任意数量的列表（至少需要一个）。
• 所有列表现在必须具有相同的长度。
• 每个列表框的宽度会根据内容自动调整。
• 列表框可以一起滚动，可以用鼠标滚轮或者滚动条。
• 应该可以在Windows、OSX和Linux上运行，但只在Linux上进行了测试。

代码：

def showLists(l, *lists):
    """
    Present passed equal-length lists in adjacent scrollboxes.
    """
    # This exists mainly for me to start learning about Tkinter.
    # This widget reqires at least one list be passed, and as many additional
    # lists as desired.  Each list is displayed in its own listbox, with
    # additional listboxes added to the right as needed to display all lists.
    # The width of each listbox is set to match the max width of its contents.
    # Caveat: Too wide or too many lists, and the widget can be wider than the screen!
    # The listboxes scroll together, using either the scrollbar or mousewheel.

    # :TODO: Refactor as an object with methods.
    # :TODO: Move to a separate file when other widgets are built.

    # Check arguments
    if (l is None) or (len(l) < 1):
        return
    listOfLists = [l]     # Form a list of lists for subsequent processing
    listBoxes = []  # List of listboxes
    if len(lists) > 0:
        for list in lists:
            # All lists must match length of first list
            # :TODO: Add tail filling for short lists, with error for long lists
            if len(list) != len(l):
                return
            listOfLists.append(list)

    import Tkinter

    def onVsb(*args):
        """
        When the scrollbar moves, scroll the listboxes.
        """
        for lb in listBoxes:
            lb.yview(*args)

    def onMouseWheel(event):
        """
        Convert mousewheel motion to scrollbar motion.
        """
        if (event.num == 4):    # Linux encodes wheel as 'buttons' 4 and 5
            delta = -1
        elif (event.num == 5):
            delta = 1
        else:                   # Windows & OSX
            delta = event.delta
        for lb in listBoxes:
            lb.yview("scroll", delta, "units")
        # Return 'break' to prevent the default bindings from
        # firing, which would end up scrolling the widget twice.
        return "break"

    # Create root window and scrollbar
    root = Tkinter.Tk()
    root.title('Samples w/ time step < 0')
    vsb = Tkinter.Scrollbar(root, orient=Tkinter.VERTICAL, command=onVsb)
    vsb.pack(side=Tkinter.RIGHT, fill=Tkinter.Y)

    # Create listboxes
    for i in xrange(0,len(listOfLists)):
        lb = Tkinter.Listbox(root, yscrollcommand=vsb.set)
        lb.pack(side=Tkinter.LEFT, fill=Tkinter.BOTH)
        # Bind wheel events on both Windows/OSX & Linux;
        lb.bind("<MouseWheel>", onMouseWheel)
        lb.bind("<Button-4>", onMouseWheel)
        lb.bind("<Button-5>", onMouseWheel)
        # Fill the listbox
        maxWidth = 0
        for item in listOfLists[i]:
            s = str(item)
            if len(s) > maxWidth:
                maxWidth = len(s)
            lb.insert(Tkinter.END, s)
        lb.config(width=maxWidth+1)
        listBoxes.append(lb)        # Add listbox to list of listboxes

    # Show the widget
    Tkinter.mainloop()
# End of showLists()

欢迎提出改进建议！

Answer 2

我知道这个问题已经有点老了，但我觉得解决办法其实比这里提到的要简单一些。假设你总是希望两个列表框的内容保持一致，那么上面两个答案其实并不完整——用箭头键改变选择时，只会滚动一个列表框，而另一个不会动。

所以，看了这些答案后，我就在想——为什么他们不直接连接到yscrollcommand这个回调，而只是把它直接发送给滚动条呢？于是，我就这样做了：

try:
    from Tkinter import *
except ImportError:
    from tkinter import *


class MultipleScrollingListbox(Tk):

    def __init__(self):
        Tk.__init__(self)
        self.title('Scrolling Multiple Listboxes')

        #the shared scrollbar
        self.scrollbar = Scrollbar(self, orient='vertical')

        #note that yscrollcommand is set to a custom method for each listbox
        self.list1 = Listbox(self, yscrollcommand=self.yscroll1)
        self.list1.pack(fill='y', side='left')

        self.list2 = Listbox(self, yscrollcommand=self.yscroll2)
        self.list2.pack(expand=1, fill='both', side='left')

        self.scrollbar.config(command=self.yview)
        self.scrollbar.pack(side='right', fill='y')

        #fill the listboxes with stuff
        for x in xrange(30):
            self.list1.insert('end', x)
            self.list2.insert('end', x)

    #I'm sure there's probably a slightly cleaner way to do it than this
    #Nevertheless - whenever one listbox updates its vertical position,
    #the method checks to make sure that the other one gets updated as well.
    #Without the check, I *think* it might recurse infinitely.
    #Never tested, though.
    def yscroll1(self, *args):
        if self.list2.yview() != self.list1.yview():
            self.list2.yview_moveto(args[0])
        self.scrollbar.set(*args)

    def yscroll2(self, *args):
        if self.list1.yview() != self.list2.yview():
            self.list1.yview_moveto(args[0])
        self.scrollbar.set(*args)

    def yview(self, *args):
        self.list1.yview(*args)
        self.list2.yview(*args)


if __name__ == "__main__":
    root = MultipleScrollingListbox()
    root.mainloop()

Answer 3

解决这个问题的方法和你之前把两个小部件连接到一个滚动条的方法差不多：为鼠标滚轮创建自定义绑定，让这些绑定同时影响两个列表框，而不仅仅是一个。

唯一需要注意的地方是，不同的平台会给鼠标滚轮发送不同的事件：在Windows和Mac上会收到<MouseWheel>事件，而在Linux上则会收到<Button-4>和<Button-5>事件。

下面是一个例子，我在我的Mac上用python 2.5测试过：

import Tkinter as tk

class App:
    def __init__(self):
        self.root=tk.Tk()
        self.vsb = tk.Scrollbar(orient="vertical", command=self.OnVsb)
        self.lb1 = tk.Listbox(self.root, yscrollcommand=self.vsb.set)
        self.lb2 = tk.Listbox(self.root, yscrollcommand=self.vsb.set)
        self.vsb.pack(side="right",fill="y")
        self.lb1.pack(side="left",fill="x", expand=True)
        self.lb2.pack(side="left",fill="x", expand=True)
        self.lb1.bind("<MouseWheel>", self.OnMouseWheel)
        self.lb2.bind("<MouseWheel>", self.OnMouseWheel)
        for i in range(100):
            self.lb1.insert("end","item %s" % i)
            self.lb2.insert("end","item %s" % i)
        self.root.mainloop()

    def OnVsb(self, *args):
        self.lb1.yview(*args)
        self.lb2.yview(*args)

    def OnMouseWheel(self, event):
        self.lb1.yview("scroll", event.delta,"units")
        self.lb2.yview("scroll",event.delta,"units")
        # this prevents default bindings from firing, which
        # would end up scrolling the widget twice
        return "break"

app=App()