當滿足某些條件時無法顯示另一個tkinter幀

Question

我正在嘗試製作一個即時消息程序，該程序在網絡驅動器上工作，並使用@Bryan Oakley的某些代碼在tkinter幀之間進行切換。第一幀應該是保存在txt文件中的用戶名的條目。如果我的程序檢測到用戶名已經保存一次，我想跳過這個框架。但是，當我嘗試這樣做時出現以下錯誤。

Traceback (most recent call last): 
    File "C:\Users\Douglas Rouse\Google Drive\Python\New structure.py", line 260, in <module> 
    app = ChatApp() 
    File "C:\Users\Douglas Rouse\Google Drive\Python\New structure.py", line 73, in __init__ 
    frame = StartPage(self.container, self) 
    File "C:\Users\Douglas Rouse\Google Drive\Python\New structure.py", line 129, in __init__ 
    self.check_user() 
    File "C:\Users\Douglas Rouse\Google Drive\Python\New structure.py", line 144, in check_user 
    ChatApp.show_frame(ChatApp,[PageOne]) 
    File "C:\Users\Douglas Rouse\Google Drive\Python\New structure.py", line 106, in show_frame 
    self.frame = self.frames[cont] 
AttributeError: type object 'ChatApp' has no attribute 'frames' 

我是相當新的Python那麼，究竟我錯在哪裏，將不勝感激的解釋！

class ChatApp(tk.Tk): 

    def __init__(self, *args, **kwargs): 
     tk.Tk.__init__(self, *args, **kwargs) 
     tk.Tk.wm_title(self,"Messenger") 

     self.container = tk.Frame(self) 
     self.container.grid() 
     self.container.grid_rowconfigure(0, weight=1) 
     self.container.grid_columnconfigure(0, weight=1) 


     self.frames = {} 
     frame = StartPage(self.container, self) 
     self.frame_ = PageOne(self.container, self) 
     frame1 = BanPage(self.container, self) 

     self.frames[StartPage] = frame 
     self.frames[PageOne] = self.frame_ 
     self.frames[BanPage] = frame1 

     frame.grid(row=0, column=0, sticky="nsew") 
     self.frame_.grid(row=0, column=0, sticky="nsew") 

     self.show_frame(StartPage) 
     #ban() 




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


class StartPage(tk.Frame): 

    def __init__(self, parent, controller,*args): 
     tk.Frame.__init__(self, parent) 
     usrlabel = ttk.Label(self, text="Input Username", font=LARGE_FONT) 
     usrlabel.grid(pady=10,padx=10) 
     self.usrentry = ttk.Entry(self) 
     self.usrentry.grid() 
     StartPage.uu = self.usrentry.get() 

     #command within button cant throw args to funcs. Use lambda to throw those args to the func instead 
     button1 = ttk.Button(self, text="Visit Page 1",command= 
          lambda: controller.show_frame(PageOne)) 
     button1.grid() 
     Button2 = ttk.Button(self, text = "test",command = self.save_user) 
     Button2.grid() 
     self.check_user() 

    def save_user(self,*args): 
     usr = open("user.txt","a") 
     self.public_usr = open("publicusr.txt","a") 
     self.public_usr.write(self.usrentry.get()) 
     usr.write(self.usrentry.get()) 
     self.usrentry.delete(0, 'end') 

    def check_user(self): 
     usrcount=0 
     with open ("user.txt","rb") as usr: 
      for line in usr: 
       usrcount+=1 
      if usrcount == 1: 
       ChatApp.show_frame(ChatApp,[PageOne]) 
       print(usrcount) 

Answer 1

這行代碼導致了問題：

ChatApp.show_frame(ChatApp,[PageOne]) 

你叫show_frame不是一個實例ChatApp，但類對象本身。類沒有屬性，這就是爲什麼你得到錯誤「‘ChatApp’有沒有屬性‘框架’」

你不能在類叫show_frame，你必須調用它的類的實例。在你的情況下，實例將以controller的形式傳入，你需要保存這個以便稍後使用它。

class StartPage(tk.Frame): 

    def __init__(self, parent, controller,*args): 
     self.controller = controller 
     ... 

    def check_user(self): 
     ... 
      if usrcount == 1: 
       self.controller.show_frame(PageOne) 
       ... 

我想你也會有問題show_frame被調用之前，它是以外的任何其他一個空的字典。這是因爲您在創建StartPage時立即致電check_user，這發生在將任何內容插入到self.frames之前。