Tkinter多幀事件

Question

我嘗試通過Tkinter GUI。該代碼如下， 目標是每1秒顯示消息「本頁xxx」。當我打開每個幀相同

1. 當我打開一個頁面將顯示消息「這是一個網頁」每隔1秒
2. 當我打開兩個頁面將顯示消息「這是兩頁的」每1第二（不顯示消息頁面之一）

（對不起我的所有解釋英語不太好）

import Tkinter as tk 
LARGE_FONT= ("Verdana", 12) 

class Application(tk.Tk): 

    def __init__(self, *args, **kwargs): 

     tk.Tk.__init__(self, *args, **kwargs) 
     container = tk.Frame(self, bg='red') 
     container.pack(side="top", fill="both", expand = True) 

     self.val1 = "chain" 

     container.grid_rowconfigure(0, weight=1) 
     container.grid_columnconfigure(0, weight=1) 

     self.frames = {} 
     self.collection = (StartPage, PageOne, PageTwo) 

     for F in self.collection: 
      frame = F(container, self) 
      self.frames[F] = frame 
      frame.grid(row=0, column=0, sticky="nsew") 
     self.show_frame(StartPage) 

    def show_frame(self, cont): 
     frame = self.frames[cont] 
     frame.tkraise() 

    def printdata(self, data): 
     print data 


class StartPage(tk.Frame): 

    def __init__(self, parent, controller): 
     tk.Frame.__init__(self,parent) 
     self.master = controller 
     self.configure(background='green') 
     label = tk.Label(self, text="Start Page", font=LARGE_FONT) 
     label.pack(pady=10,padx=10) 

     button = tk.Button(self, text="Visit Page 1", command=lambda: controller.show_frame(PageOne)) 
     button.pack() 

     button2 = tk.Button(self, text="Visit Page 2", command=lambda: self.gopagetwo()) 
     button2.pack() 

    def gopagetwo(self): 
     PageTwo.mymessage() 
     self.master.show_frame(PageTwo) 

    def mymessage(self): 
     print 'This is page initial.' 
     self.after(1000, self.mymessage) 


class PageOne(tk.Frame): 

    def __init__(self, parent, controller): 
     tk.Frame.__init__(self, parent, bg='yellow') 
     self.master = controller 
     self.label = tk.Label(self, text="Page One!!!", font=LARGE_FONT) 
     self.label.pack(pady=5,padx=10) 
     self.lblCounter = tk.Label(self, text="Counter", font=LARGE_FONT) 
     self.lblCounter.pack(pady=5,padx=10) 
     self.lblStartTime = tk.Label(self, text="time start", font=LARGE_FONT) 
     self.lblStartTime.pack(pady=5,padx=10) 
     self.lblStartNow = tk.Label(self, text="time now", font=LARGE_FONT) 
     self.lblStartNow.pack(pady=5,padx=10) 

     button1 = tk.Button(self, text="Back to Home", 
          command=lambda: controller.show_frame(StartPage)) 
     button1.pack() 

    def mymessage(self): 
     print 'This is page one.' 
     self.after(1000, self.mymessage) 


class PageTwo(tk.Frame): 

    def __init__(self, parent, controller): 
     tk.Frame.__init__(self, parent, bg='pink') 
     self.master = controller 
     label = tk.Label(self, text="Page Two!!!", font=LARGE_FONT) 
     label.pack(pady=5,padx=10) 
     self.lblCounter = tk.Label(self, text="Counter", font=LARGE_FONT) 
     self.lblCounter.pack(pady=5,padx=10) 
     self.lblStartTime = tk.Label(self, text="time start", font=LARGE_FONT) 
     self.lblStartTime.pack(pady=5,padx=10) 
     self.lblStartNow = tk.Label(self, text="time now", font=LARGE_FONT) 
     self.lblStartNow.pack(pady=5,padx=10) 

     button1 = tk.Button(self, text="Back to Home", 
          command=lambda: controller.show_frame(StartPage)) 
     button1.pack() 

    def mymessage(self): 
     print 'This is page two.' 
     self.after(1000, self.myssage) 


app = Application() 
app.mainloop() 

Answer 1

有代碼中的幾個問題。

首先，在StartPage.gopagetwo中，調用PageTwo.mymessage()無法工作，因爲mymessage是一個實例方法，它需要一個PageTwo實例才能正常工作。

您可以嘗試通過在Application.show_frame中添加對frame.mymessage()的調用來達到您想要的行爲。但是，您會發現它不會爲當前幀打印消息，而是會爲每個訪問幀（並通過訪問）打印一條消息。如果你遵循這個軌道，你將不得不在某個地方存儲以後的綁定，並提供一箇中止它的選項。

class StartPage(tk.Frame): 
    #... 
    def mymessage(self): 
     print 'This is page initial.' 
     self.after_id = self.after(1000, self.mymessage) 

    def end_mymessageloop(self): 
     self.after_cancel(self.after_id) 

和適應show_frame：

class Application(tk.Tk): 
    #... 
    def show_frame(self, cont): 
     if hasattr(self,"current_frame"): 
      self.current_frame.end_mymessageloop() 
     frame = self.frames[cont] 
     frame.tkraise() 
     frame.mymessage() 
     self.current_frame = frame 

---

然而，你可能會發現簡單的只具有循環結束後的這一個實例委託print語句的幀（並刪除在後循環每個mymessage）。

class Application(tk.Tk): 
    def __init__(self, *args, **kwargs): 
     #... 
     self.show_frame(StartPage) 
     self.status_message() 

    def show_frame(self, cont): 
     frame = self.frames[cont] 
     frame.tkraise() 
     self.current_frame = frame 

    def status_message(self): 
     self.current_frame.mymessage() 
     self.after(1000, self.status_message)