将函数作为参数传递

Question

我知道这里非常基本的东西是错误的，我只是看不到。如果有人在Python方面有经验，可以指出我在这里误解了什么地方，我真的很感激。我在下面发布我的代码的简化版本。追溯问题开始的地方，对下列的眼睛：

的MainProgram，实例化作为Main = MainProgram()，有一个菜单（self.menu = Startmenu()），这是Menu类的一个实例。这个Menu类有一个按钮列表（self.buttons = [...]） - 在这种情况下只有一个。它们是Button类的一个实例。我现在需要传递该按钮被点击时触发的函数给类的实例，所以我可以真正使用它。

我真的很感谢任何有经验的用户快速浏览它。我相信我没有看到非常基本的东西。我敢打赌，我太累了，看到它... ...只有约2个小时的睡眠，因为有一个在家里一个宝宝现在：d

我的代码：

class MainProgram: 
    #Much much more code 
    def __init__(self): 
     #And so much more code here 
     self.menu = StartMenu() 

class StartMenu: 
    def __init__(self): 
     #Much code which is not important to us here 
     self.buttons = [Button("d_bt_start", (100, 60) 
             , testfunc, "TEST-TEXT")] 

class Button: 
    def __init__(self, image, pos = (0, 0), path = Paths.path_img 
       , alpha = False, func = None, args = None): 
     self.img_normal = helper.loadImage(path, image + "_normal.jpg", alpha) 
     self.img_hover = helper.loadImage(path, image + "_hover.jpg", alpha) 

     self.image = self.img_normal 

     self.pos = pos 

     self.x = pos[0] 
     self.y = pos[1] 
     self.width = self.x + self.image.get_width() 
     self.height = self.y + self.image.get_height() 

     self.mouseover = 0 

     self.func = func 
     self.args = args 

    def update(self, (mx, my)): 
     if (mx >= self.x and mx <= self.width and 
      my >= self.y and my <= self.height): 
      if self.mouseover == 0: 
       self.image = self.img_hover 
       self.mouseover = 1 
     else: 
      if self.mouseover == 1: 
       self.image = self.img_normal 
       self.mouseover = 0 

    def clicked(self, button): 
     if (mx >= self.x and mx <= self.width and 
      my >= self.y and my <= self.height): 
      if button == 1: 
       self.func(self.args) 

应该发生的事情：主文件创建一个StartMenu类的实例。在StartMenu类中，我们将一个按钮定义为Button类的实例。点击该按钮应该触发功能testfunc(args)。这个测试函数到目前为止只是“TEST-TEXT”参数的打印。

如果我通过功能

testfunc 

然后我收到以下错误回溯：

Traceback (most recent call last): 
    File "D:\Python27\_RPG DEMO\DEMO\main.py", line 41, in <module> 
    Main = MainProgram() 
    File "D:\Python27\_RPG DEMO\DEMO\main.py", line 21, in __init__ 
    self.menu = menus.StartMenu() 
    File "D:\Python27\_RPG DEMO\DEMO\menus.py", line 11, in __init__ 
    , zztestfile.testfunc, "TESTEST") 
    File "D:\Python27\_RPG DEMO\DEMO\buttons.py", line 7, in __init__ 
    self.img_normal = helper.loadImage(path, image + "_normal.jpg", alpha) 
    File "D:\Python27\_RPG DEMO\DEMO\helper.py", line 13, in loadImage 
    return pygame.image.load(os.path.join(folder, name)).convert_alpha() 
    File "D:\Python27\lib\ntpath.py", line 96, in join 
    assert len(path) > 0 
TypeError: object of type 'function' has no len() 

如果我把它作为：

testfunc("TEST-TEXT") 

它触发但随后的原因以下Traceback：

TEST-TEXT 

Traceback (most recent call last): 
    File "D:\Python27\_RPG DEMO\DEMO\main.py", line 41, in <module> 
    Main = MainProgram() 
    File "D:\Python27\_RPG DEMO\DEMO\main.py", line 21, in __init__ 
    self.menu = menus.StartMenu() 
    File "D:\Python27\_RPG DEMO\DEMO\menus.py", line 11, in __init__ 
    , testfunc("TEST-TEXT")) 
    File "D:\Python27\_RPG DEMO\DEMO\buttons.py", line 7, in __init__ 
    self.img_normal = helper.loadImage(path, image + "_normal.jpg", alpha) 
    File "D:\Python27\_RPG DEMO\DEMO\helper.py", line 15, in loadImage 
    return pygame.image.load(os.path.join(folder, name)).convert() 
    File "D:\Python27\lib\ntpath.py", line 96, in join 
    assert len(path) > 0 
TypeError: object of type 'NoneType' has no len() 

到目前为止我已经经历了一些教程，但我真的无法弄清楚我误解他们的地方。我非常感谢这方面的帮助！

Answer 1

你是通过你的测试功能，您Button类的path说法：

self.buttons = [Button("d_bt_start", (100, 60) 
           , testfunc, "TEST-TEXT")] 

这是第三位置参数有：

def __init__(self, image, pos = (0, 0), path = Paths.path_img 
      , alpha = False, func = None, args = None): 

与path匹配起来。改为使用关键字参数：

self.buttons = [Button("d_bt_start", (100, 60) 
           , func=testfunc, args="TEST-TEXT")]