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使用函数[duplicate]在tkinter中的帧之间切换

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  • ogeretal  · 技术社区  · 8 年前

    从Bryan Oakley给出的答案到tkinter中两个框架之间的问题切换,我试图改变第二页中按钮的工作方式。

    command=lambda: controller.show_frame(“StartPage”) ,它可以正常工作。

    为什么我的回调没有被调用?

    import tkinter as tk                # python 3
    from tkinter import font  as tkfont # python 3
    
    class SampleApp(tk.Tk):
    
        def __init__(self, *args, **kwargs):
            tk.Tk.__init__(self, *args, **kwargs)
    
            self.title_font = tkfont.Font(family='Helvetica', size=18, weight="bold", slant="italic")
    
            # the container is where we'll stack a bunch of frames
            # on top of each other, then the one we want visible
            # will be raised above the others
            container = tk.Frame(self)
            container.pack(side="top", fill="both", expand=True)
            container.grid_rowconfigure(0, weight=1)
            container.grid_columnconfigure(0, weight=1)
    
            self.frames = {}
            for F in (StartPage, PageOne, PageTwo):
                page_name = F.__name__
                frame = F(parent=container, controller=self)
                self.frames[page_name] = frame
    
                # put all of the pages in the same location;
                # the one on the top of the stacking order
                # will be the one that is visible.
                frame.grid(row=0, column=0, sticky="nsew")
    
            self.show_frame("StartPage")
    
        def show_frame(self, page_name):
            '''Show a frame for the given page name'''
            frame = self.frames[page_name]
            frame.tkraise()
    
    
    class StartPage(tk.Frame):
    
        def __init__(self, parent, controller):
            tk.Frame.__init__(self, parent)
            self.controller = controller
            label = tk.Label(self, text="This is the start page", font=controller.title_font)
            label.pack(side="top", fill="x", pady=10)
    
            button1 = tk.Button(self, text="Go to Page One",
                                command=lambda: controller.show_frame("PageOne"))
            button2 = tk.Button(self, text="Go to Page Two",
                                command=lambda: controller.show_frame("PageTwo"))
            button1.pack()
            button2.pack()
    
    
    class PageOne(tk.Frame):
    
        def __init__(self, parent, controller):
            tk.Frame.__init__(self, parent)
            self.controller = controller
            label = tk.Label(self, text="This is page 1", font=controller.title_font)
            label.pack(side="top", fill="x", pady=10)
            button = tk.Button(self, text="Go to the start page",
                               command=lambda: controller.show_frame("StartPage"))
            button.pack()
    
    
    class PageTwo(tk.Frame):
    
        def __init__(self, parent, controller):
            tk.Frame.__init__(self, parent)
            self.controller = controller
            label = tk.Label(self, text="This is page 2", font=controller.title_font)
            label.pack(side="top", fill="x", pady=10)
            button = tk.Button(self, text="Go to the start page",
                               command=self.go_to())
            button.pack()
        def go_to(self):
            # Add something to do            
            self.controller.show_frame("StartPage")
    
    
    if __name__ == "__main__":
        app = SampleApp()
        app.mainloop()
    
    1 回复  |  直到 8 年前
        1
  •  0
  •   Right leg A.s. Bhullar    8 年前

    问题是 command 的关键字参数 Button 需要一个函数。 创建按钮时使用 tk.Button(self, ..., command=self.go_to()) self.go_to() ,其计算结果为 None

    为什么会这样? go_to 定义如下:

    def go_to(self):
        # Add something to do 
        self.controller.show_frame("StartPage")
    

    command=self.go_to() ,它调用 转到 命令 选项 该值为 (由缺少 return 没有一个

    tk.Button(self, ..., command=self.go_to) .