tkinter multi-Toplevel windows 当只有一个窗口释放抓取状态时释放所有窗口grab_set

Question

我正在尝试使用具有多个级别窗口的 tkinter 构建 GUI。当我打开一个新的顶级窗口时，我需要抓住他的括号。为此，我在 Toplevel 类的开头使用了grab_set()。

新的顶层子窗口还将具有一些其他功能，允许打开新的顶层孙子窗口。问题是，当任何顶层孙窗口关闭时，处于抓取状态的窗口的层次结构会被释放，然后它们都可以再次被操作。

当一个grab_settled 孙子窗口被释放时，我如何维护grab_set() 函数对所有窗口都有效？

这是一个重现此行为的简单代码示例

from tkinter import *


class GUI(Frame):
    def __init__(self, master, *args, **kwargs):
        Frame.__init__(self, master, *args, **kwargs)

        self.master = master
        self.my_frame = Frame(self.master)
        self.my_frame.pack()

        self.button1 = Button(self.master, text="Open New Window", command=OpenFirstToplevelWindow)
        self.button1.pack()

        self.text = Text(self.master, width=30, height=3)
        self.text.pack()
        self.text.insert(END, "Some text")


class OpenFirstToplevelWindow(Toplevel):
    def __init__(self, *args, **kwargs):
        Toplevel.__init__(self, *args, **kwargs)
        self.grab_set()
        top_button = Button(self, text="Open a second window", command=OpenSecondToplevelWindow)
        top_button.pack()
        app.text.delete(1.0, END)
        app.text.insert(END, "Text edition should be inhibited")
        # Toplevel.wait_window(self)


class OpenSecondToplevelWindow(Toplevel):
    def __init__(self, *args, **kwargs):
        Toplevel.__init__(self, *args, **kwargs)
        self.grab_set()
        top_button = Button(self, text="close second window", command=self.close_window)
        top_button.pack()
        app.text.delete(1.0, END)
        app.text.insert(END, "Text edition still inhibited")

    def close_window(self):
        app.text.delete(1.0, END)
        app.text.insert(END, "Text edition should keep inhibited but it IS NOT")
        self.destroy()


if __name__ == "__main__":
    root = Tk()
    app = GUI(root)
    root.mainloop()

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--- 编辑扩展@acw1668 答案---

---

我一直在研究您的答案，看起来效果很好。问题是我已经意识到，如果我尝试将self 放在最后一个窗口中的关闭按钮的名称以供进一步使用，那么该方法不起作用：

class OpenSecondToplevelWindow(MyToplevel):
    def __init__(self, *args, **kwargs):
        MyToplevel.__init__(self, *args, **kwargs)
        enable_button = Button(self, text="Enable close button", command=self.enable_click)
        enable_button.pack()
        self.low_button = Button(self, text="Close second window", command=self.close_window, state=DISABLED)
        self.low_button.pack()
        app.text.delete(1.0, END)
        app.text.insert(END, "Text edition still inhibited")

    def enable_click(self):
        self.low_button["state"] = NORMAL

    def close_window(self):
        app.text.delete(1.0, END)
        app.text.insert(END, "Text edition should keep inhibited but it IS NOT")
        self.destroy()

Answer 1

其中一种方法是在调用grab_set() 之前保存已设置抓取的窗口的引用（如果有）。然后在当前窗口关闭后将抓取集恢复到保存的窗口。

以下自定义类（继承自Toplevel）将具有上述功能：

class MyToplevel(Toplevel):
    def __init__(self, master=None, **kw):
        super().__init__(master, **kw)
        # save the reference of current window having the grab set
        self._last_grab_set_win = self.grab_current()
        self.grab_set()

    def __del__(self):
        if self._last_grab_set_win:
            # restore the grab set to saved window
            self._last_grab_set_win.grab_set()

然后在你的代码中使用上面自定义的MyToplevel，而不是Toplevel：

class OpenFirstToplevelWindow(MyToplevel):
    def __init__(self, *args, **kwargs):
        MyToplevel.__init__(self, *args, **kwargs)
        top_button = Button(self, text="Open a second window", command=OpenSecondToplevelWindow)
        top_button.pack()
        app.text.delete(1.0, END)
        app.text.insert(END, "Text edition should be inhibited")
        # Toplevel.wait_window(self)


class OpenSecondToplevelWindow(MyToplevel):
    def __init__(self, *args, **kwargs):
        MyToplevel.__init__(self, *args, **kwargs)
        top_button = Button(self, text="close second window", command=self.close_window)
        top_button.pack()
        app.text.delete(1.0, END)
        app.text.insert(END, "Text edition still inhibited")

    ...

更新：如果使用实例小部件而不是本地小部件，我不知道为什么不执行 __del__()。但是，覆盖 destroy() 似乎可以解决问题：

class MyToplevel(Toplevel):
    def __init__(self, master=None, **kw):
        super().__init__(master, **kw)
        # save the reference of current window having the grab set
        self._last_grab_set_win = self.grab_current()
        self.grab_set()

    # override destroy()
    def destroy(self):
        if self._last_grab_set_win:
            # restore the grab set to saved window
            self._last_grab_set_win.grab_set()
        # call Toplevel.destroy()
        super().destroy()