tkinter中的可滚动帧类

Question

我在tkinter中实现了自己的可滚动框架类：

class scrolledFrame(tk.Frame):
    def __init__(self, parent):
        tk.Frame.__init__(self, parent)
        self.canvas = tk.Canvas(self)
        self.canvas.pack(fill = "both", expand = True, side = "left")
        self.scroll = tk.Scrollbar(self, command = self.canvas.yview)
        self.scroll.pack(side = "right", fill = "y")
        self.canvas.config(yscrollcommand = self.scroll.set)
        self.content = tk.Frame(self.canvas)
        self.content.bind("<Configure>", self.resizeCanvas)
        self.contentWindow = self.canvas.create_window((0,0), window = self.content, anchor = "nw")
        self.content.bind("<Enter>", self.enableScrollCanvas)
        self.content.bind("<Leave>", self.disableScrollCanvas)
    def scrollCanvas(self, event):
        self.canvas.yview_scroll(int(-1*(event.delta/120)), "units")
    def enableScrollCanvas(self, event):
        self.canvas.bind_all("<MouseWheel>", self.scrollCanvas)
    def disableScrollCanvas(self, event):
        self.canvas.unbind_all("<MouseWheel>")
    def resizeCanvas(self, event):
        self.update_idletasks()
        self.canvas.config(scrollregion = self.canvas.bbox("all"))
        self.canvas.itemconfig(self.contentWindow, width = self.canvas.winfo_width())

root = tk.Tk()
exampleFrame = scrolledFrame(root)
exampleFrame.pack()
exampleLabel = tk.Label(exampleFrame.content, text = "I'm in the scrolled frame!")
exampleLabel.pack()
root.mainloop()

这很好，但问题是要将小部件添加到滚动框中，父对象必须是exampleFrame.content。我看过其他几个例子，它们都有相同的局限性。是否可以将类配置为exampleFrame可以作为小部件的父级而不是exampleFrame.content？提前谢谢

Answer 1

感谢@Novel帮助回答这个问题。
通过向类中添加__getattr__方法，可以实现所需的行为。如果类从tk.Frame继承，因此该类已被删除，那么这将不起作用。代码如下：

class scrolledFrame():
    def __init__(self, parent):
        self.wrapper = tk.Frame(parent)
        self.canvas = tk.Canvas(self.wrapper)
        self.canvas.pack(fill = "both", expand = True, side = "left")
        self.scroll = tk.Scrollbar(self.wrapper, command = self.canvas.yview)
        self.scroll.pack(side = "right", fill = "y")
        self.canvas.config(yscrollcommand = self.scroll.set)
        self.content = tk.Frame(self.canvas)
        self.content.bind("<Configure>", self.resizeCanvas)
        self.contentWindow = self.canvas.create_window((0,0), window = self.content, anchor = "nw")
        self.content.bind("<Enter>", self.enableScrollCanvas)
        self.content.bind("<Leave>", self.disableScrollCanvas)
        self.attrib = set(dir(tk.Widget))
    def __getattr__(self, item):
        if item in self.attrib:
            return getattr(self.wrapper, item)
        else:
            return getattr(self.content, item)
    def __str__(self):
        return str(self.wrapper)
    def scrollCanvas(self, event):
        self.canvas.yview_scroll(int(-1*(event.delta/120)), "units")
    def enableScrollCanvas(self, event):
        self.canvas.bind_all("<MouseWheel>", self.scrollCanvas)
    def disableScrollCanvas(self, event):
        self.canvas.unbind_all("<MouseWheel>")
    def resizeCanvas(self, event):
        self.update_idletasks()
        self.canvas.config(scrollregion = self.canvas.bbox("all"))
        self.canvas.itemconfig(self.contentWindow, width = self.canvas.winfo_width())
root = tk.Tk()
exampleFrame = scrolledFrame(root)
exampleFrame.pack()
exampleLabel = tk.Label(exampleFrame, text = "I'm in the scrolled frame!")
exampleLabel.pack()
root.mainloop()

Answer 2

如果你不介意一些小把戏，你可以模拟你想要的。不过这有点像黑客

诀窍在于，当您调用tk.Frame.__init__时，需要将画布作为父对象，使self成为内容框架。当然，要做到这一点，您必须首先创建画布，要创建画布，您必须创建外部框架

它看起来像这样：

class scrolledFrame(tk.Frame):
    def __init__(self, parent):
        self.outer = tk.Frame(parent)
        self.canvas = tk.Canvas(self.outer)
        self.scroll = tk.Scrollbar(self.outer, command = self.canvas.yview)
        tk.Frame.__init__(self, self.canvas)
        self.contentWindow = self.canvas.create_window((0,0), window = self, anchor = "nw")

但是，当您执行上述操作并尝试在scrolledFrame的实例上调用pack、place或grid时，它将执行错误的操作，因为该实例指向内部框架而不是外部框架

这里有一个技巧：解决方案是将调用重定向到pack、place和grid到外部框架

class scrolledFrame(tk.Frame):
    def __init__(self, parent):
        ...
        self.pack = self.outer.pack
        self.place = self.outer.place
        self.grid = self.outer.grid

有了它，您可以随意使用scrolledFrame，只要在将它添加到布局时使用pack、place或grid

exampleFrame = scrolledFrame(root)
exampleFrame.pack(fill="both", expand=True)
for i in range(100):
    exampleLabel = tk.Label(exampleFrame, text = f"I'm in the scrolled frame! ({i})")
    exampleLabel.pack()

---

这是一个完整的工作示例，不过为了简洁起见，我删除了mouseweel代码

import tkinter as tk

class scrolledFrame(tk.Frame):
    def __init__(self, parent):
        self.outer = tk.Frame(parent)
        self.canvas = tk.Canvas(self.outer)
        self.scroll = tk.Scrollbar(self.outer, command = self.canvas.yview)
        tk.Frame.__init__(self, self.canvas)
        self.contentWindow = self.canvas.create_window((0,0), window = self, anchor = "nw")

        self.canvas.pack(fill = "both", expand = True, side = "left")
        self.scroll.pack(side = "right", fill = "y")
        self.canvas.config(yscrollcommand = self.scroll.set)
        self.bind("<Configure>", self.resizeCanvas)

        self.pack = self.outer.pack
        self.place = self.outer.place
        self.grid = self.outer.grid

    def resizeCanvas(self, event):
        self.canvas.config(scrollregion = self.canvas.bbox("all"))
        self.canvas.itemconfig(self.contentWindow, width = self.canvas.winfo_width())

root = tk.Tk()
exampleFrame = scrolledFrame(root)
exampleFrame.pack(fill="both", expand=True)
for i in range(100):
    exampleLabel = tk.Label(exampleFrame, text = f"I'm in the scrolled frame! ({i})")
    exampleLabel.pack(fill="x")
root.mainloop()