Hello World：應用程序實例沒有屬性'say_hi'

Question

我只是在學習python（有五天的時間來這樣做），而且我遇到了hello world程序的一些基本問題。任何想法，我缺少什麼？

#!/user/bin/python3 

from Tkinter import * 

class App: 
    def __init__(self, master): 
     frame = Frame(master) 
     frame.pack() 

     def say_hi(self): 
      print "Hello word!" 

     self.button = Button (frame, text="QUIT", 
      fg="red", command=frame.quit) 
     self.button.pack(side=LEFT) 

     self.hi = Button (frame, text="Hello", 
      command=self.say_hi) 
     self.button.pack(side=RIGHT) 

root = Tk() 
app = App (root) 
root.mainloop() 

我得到的錯誤是：

File "HelloWorld.py", line 22, in <module> 

app = App (root) 

File "HelloWorld.py", 

line 18, in __init__ 

command=self.say_hi) 

AttributeError: App instance has no attribute 'say_hi' 

不該def say_hi(self)：創建實例？提前致謝。

Answer 1

你的問題是你在__init__()裏面定義了say_hi()。只要將下來，並取消縮進它：

#!/user/bin/python3 

from Tkinter import * 

class App: 
    def __init__(self, master): 
     frame = Frame(master) 
     frame.pack() 

     self.button = Button (frame, text="QUIT", 
      fg="red", command=frame.quit) 
     self.button.pack(side=LEFT) 

     self.hi = Button (frame, text="Hello", 
      command=self.say_hi) 
     self.button.pack(side=RIGHT) 

    def say_hi(self): 
     print "Hello word!" 

root = Tk() 
app = App (root) 
root.mainloop() 

因爲它是，say_hi()只是在__init__()一個局部變量。如果你在__init__()以外定義它，這是一種方法。

Answer 2

您在__init__的範圍內創建say_hi。因此，它應該是：

self.hi = Button (frame, text="Hello", 
    command=say_hi) 

但你可能是指：

class App: 
    def __init__(self, master): 
     frame = Frame(master) 
     frame.pack() 

     self.button = Button (frame, text="QUIT", 
      fg="red", command=frame.quit) 
     self.button.pack(side=LEFT) 

     self.hi = Button (frame, text="Hello", 
      command=self.say_hi) 
     self.button.pack(side=RIGHT) 

    def say_hi(self): 
     print "Hello word!" 

希望這有助於！