python tkinter canvas没有调整大小

Question

我正在尝试将一些tkinter控件子类化，以便在我的程序中使用自动滚动框架，我只希望它在垂直方向上滚动，并且当添加需要它来水平滚动而不是调整父级以适合的小部件时。进入此框架的窗口小部件并非全部在运行时定义，而是动态创建的，因此它必须对事件做出反应。我有一些部分工作的代码，因为我运行它，我可以使用底部的按钮来动态添加和删除标签，如果我这样做而不先手动调整窗口大小然后它按预期工作。但是，如果我手动调整窗口大小，水平调整大小将停止工作：

from tkinter import *

__all__ = ["VerticalScrolledFrame"]

class VerticalScrolledFrame(Frame):
    def __init__(self, parent, *args, **kw):
        Frame.__init__(self, parent, *args, **kw)            
        self.grid_columnconfigure(1, weight=1)
        self.grid_rowconfigure(1, weight=1)
        # create a canvas object and a vertical scrollbar for scrolling it
        self.vscrollbar = Scrollbar(self, orient=VERTICAL)
        self.vscrollbar.grid(column=2, row=1, sticky="nesw")
        self.canvas = Canvas(self, bd=0, highlightthickness=0, yscrollcommand=self.vscrollbar.set, height=10, width=10)
        self.canvas.grid(column=1, row=1, sticky="nesw")
        self.vscrollbar.config(command=self.canvas.yview)

        # reset the view
        self.canvas.xview_moveto(0)
        self.canvas.yview_moveto(0)

        # create a frame inside the canvas which will be scrolled with it
        self.interior = Frame(self.canvas)
        self.interior_id = self.canvas.create_window(0, 0, window=self.interior, anchor=NW)

        self.interior.bind('<Configure>', self._configure_interior)

        # track changes to the canvas and frame width and sync them,
        # also updating the scrollbar
    def _configure_interior(self, event=None):
        print("config interior")
        # update the scrollbars to match the size of the inner frame
        size = (self.interior.winfo_width(), self.interior.winfo_height())
        self.canvas.config(scrollregion="0 0 %s %s" % size)
        if self.interior.winfo_reqwidth() > self.canvas.winfo_width():
            # update the canvas's width to fit the inner frame
            self.canvas.config(width=self.interior.winfo_reqwidth())

if __name__ == "__main__":
    labels = []
    labels2 = []
    def add1():
        l = Label(f.interior, text=str(len(labels)+1))
        l.grid(column=len(labels)+1, row=1)
        labels.append(l)

    def remove1():
        l = labels.pop()
        l.grid_forget()
        l.destroy()

    def add2():
        l = Label(f.interior, text=str(len(labels2)+1))
        l.grid(column=1, row=len(labels2)+1)
        labels2.append(l)

    def remove2():
        l = labels2.pop()
        l.grid_forget()
        l.destroy()

    app = Tk()
    app.grid_columnconfigure(1, weight=1)
    app.grid_columnconfigure(2, weight=1)
    app.grid_rowconfigure(1, weight=1)
    f = VerticalScrolledFrame(app)
    f.grid(column=1, row=1, columnspan=2, sticky="nesw")
    Button(app, text="Add-H", command=add1).grid(column=1, row=2, sticky="nesw")
    Button(app, text="Remove-H", command=remove1).grid(column=2, row=2, sticky="nesw")
    Button(app, text="Add-V", command=add2).grid(column=1, row=3, sticky="nesw")
    Button(app, text="Remove-V", command=remove2).grid(column=2, row=3, sticky="nesw")
    app.mainloop()

我只在Windows上工作并使用python 3.3，我也试过3.4但没有改变。

为什么调整窗口大小会停止调用：

self.canvas.config(width=self.interior.winfo_reqwidth())

从工作？

编辑： Brian Oakley的回答是有道理的，所以我可以理解这种行为，但是我现在已经改变了我的代码，以便在调整窗口大小时处理画布大小的更改：

from tkinter import *

__all__ = ["VerticalScrolledFrame"]

class VerticalScrolledFrame(Frame):
    def __init__(self, parent, *args, **kw):
        Frame.__init__(self, parent, *args, **kw)
        p = parent
        while True:
            if p.winfo_class() in ['Tk', 'Toplevel']:
                break
            else:
                p = self._nametowidget(p.winfo_parent())
        self.root_window = p
        self.grid_columnconfigure(1, weight=1)
        self.grid_rowconfigure(1, weight=1)
        # create a canvas object and a vertical scrollbar for scrolling it
        self.vscrollbar = Scrollbar(self, orient=VERTICAL)
        self.vscrollbar.grid(column=2, row=1, sticky="nesw")
        self.canvas = Canvas(self, bd=0, highlightthickness=0, yscrollcommand=self.vscrollbar.set, height=10, width=10)
        self.canvas.grid(column=1, row=1, sticky="nesw")
        self.vscrollbar.config(command=self.canvas.yview)

        # reset the view
        self.canvas.xview_moveto(0)
        self.canvas.yview_moveto(0)

        # create a frame inside the canvas which will be scrolled with it
        self.interior = Frame(self.canvas)
        self.interior_id = self.canvas.create_window(0, 0, window=self.interior, anchor=NW)

        self.interior.bind('<Configure>', self._configure_interior)

        self.canvas.bind('<Configure>', self._configure_canvas)

        # track changes to the canvas and frame width and sync them,
        # also updating the scrollbar
    def _configure_interior(self, event=None):
        print("config interior")
        # update the scrollbars to match the size of the inner frame
        size = (self.interior.winfo_width(), self.interior.winfo_height())
        self.canvas.config(scrollregion="0 0 %s %s" % size)
        if self.interior.winfo_reqwidth() >= self.canvas.winfo_width():
            # update the canvas's width to fit the inner frame
            # only works before mainloop
            self.canvas.config(width=self.interior.winfo_reqwidth())
        screen_h = self.winfo_screenheight()
        if ((self.root_window.winfo_rooty() + self.root_window.winfo_height() - self.canvas.winfo_height() + self.interior.winfo_reqheight()) < screen_h):
            self.canvas.configure(height=self.interior.winfo_reqheight())

    def _configure_canvas(self, event=None):
        print("config canvas")
        if self.interior.winfo_reqwidth() < self.canvas.winfo_width():
            self.canvas.itemconfigure(self.interior_id, width=self.canvas.winfo_width())
        elif self.interior.winfo_reqwidth() > self.canvas.winfo_width():
            self.canvas.config(width=self.interior.winfo_reqwidth())

        if (self.interior.winfo_reqheight() < self.canvas.winfo_height()) or (self.interior.winfo_height() < self.canvas.winfo_height()):
            self.canvas.itemconfigure(self.interior_id, height=self.canvas.winfo_height())

if __name__ == "__main__":
    labels = []
    labels2 = []
    def add1():
##        app.geometry("")
        l = Label(f.interior, text=str(len(labels)+1))
        l.grid(column=len(labels)+1, row=1)
        f.interior.grid_columnconfigure(len(labels)+1, weight=1, minsize=l.winfo_reqwidth())
        labels.append(l)

    def remove1():
##        app.geometry("")
        l = labels.pop()
        l.grid_forget()
        f.interior.grid_columnconfigure(len(labels)+2, weight=0, minsize=0)
        l.destroy()

    def add2():
        l = Label(f.interior, text=str(len(labels2)+1))
        l.grid(column=1, row=len(labels2)+1)
        f.interior.grid_rowconfigure(len(labels2)+1, weight=1, minsize=l.winfo_reqheight())
        labels2.append(l)

    def remove2():
        l = labels2.pop()
        l.grid_forget()
        f.interior.grid_rowconfigure(len(labels2)+2, weight=0, minsize=0)
        l.destroy()

    app = Tk()
    app.grid_columnconfigure(1, weight=1)
    app.grid_columnconfigure(2, weight=1)
    app.grid_rowconfigure(1, weight=1)
    f = VerticalScrolledFrame(app)
    f.grid(column=1, row=1, columnspan=2, sticky="nesw")
    Button(app, text="Add-H", command=add1).grid(column=1, row=2, sticky="nesw")
    Button(app, text="Remove-H", command=remove1).grid(column=2, row=2, sticky="nesw")
    Button(app, text="Add-V", command=add2).grid(column=1, row=3, sticky="nesw")
    Button(app, text="Remove-V", command=remove2).grid(column=2, row=3, sticky="nesw")
    for i in range(0,10):
        add1()
        add2()
    app.mainloop()

我现在看到的问题是，如果我在调整窗口大小之前垂直添加项目，则会为添加的每个窗口小部件调用_configure_interior函数，并且窗口要么垂直调整大小以适合（如果在窗口大小调整之前）如果没有，它应该更新滚动区域（和滚动条），但是在调整窗口大小后，_configure_interior在添加每个小部件时停止调用，如果我手动调用它，滚动条仍然没有更新？< / p>

Answer 1

  

为什么调整窗口大小会停止调用：

     

self.canvas.config（宽度= self.interior.winfo_reqwidth（））

这是因为您的代码绑定到 frame 更改。当用户调整窗口大小时，您需要调整窗口的大小，而不是框架。如果希望在调整窗口大小时调用该函数，除了自动调整内部框架大小外，还必须将其绑定或类似于调整窗口或画布大小的功能。

您还需要注意，如果用户调整窗口大小，则在画布中向框架添加对象不会使窗口变大。用户对窗口大小的选择将覆盖正在调整大小的内部窗口小部件的计算大小。您必须将几何图形重置为空字符串才能使其自动增长。