继承中的 nameError答案

【问题标题】：nameError within Inheritance继承中的 nameError
【发布时间】：2020-02-02 21:26:21
【问题描述】：

程序运行时出现此错误：

Traceback (most recent call last):
  File "G:/assets/gametest1.py", line 141, in <module>
    cam = camera(318,0,220)
  File "G:/gametest1.py", line 85, in __init__
    super(camera,self).__init__(playerposX,characterPosX,y)
NameError: name 'characterPosX' is not defined

播放器类

class player:
    def __init__(self, playerposX,characterPosX,y):
        self.playerposX = playerposX
        self.y = y
        self.width = 88
        self.height = 135
        self.standing = True
        self.left = False
        self.right = True
        self.vel = 15
        self.jumping = False
        self.jumpCount = 10
        self.attacking = False
        self.characterPosX = characterPosX

上面是玩家类的构造函数代码，代码的目的是让屏幕随着玩家的移动而滚动，最终在达到地图限制时停止


    def move(self, playerposX, y):
        self.k = pygame.key.get_pressed()
        if self.k[pygame.K_LEFT] and self.playerposX > 0 - 45:
            self.left = True
            self.right = False
            self.playerposX -= self.vel
            self.standing = False
        elif self.k[pygame.K_RIGHT] and self.playerposX < 1500 - 90:
            self.right = True
            self.left = False
            self.standing = False
            self.playerposX += self.vel
        else:
            self.standing = True

    def jump(self, y):
        if not (self.jumping):  # checks if user's jumping intiating jump
            if self.k[pygame.K_SPACE]:
                self.jumping = True
        else:
            if self.jumpCount >= -10:
                neg = 1
                if self.jumpCount < 0:
                    neg = -1
                self.y -= (self.jumpCount ** 2) * 0.5 * neg
                self.jumpCount -= 1
            else:
                self.jumping = False
                self.jumpCount = 10

    def draw(self, win):
        wLeft = pygame.image.load('runningleft.png')
        wRight = pygame.image.load('running.png')
        char = [pygame.image.load('idleright.png'), pygame.image.load('idleleft.png')]
        attack = [pygame.image.load('attackleft.png'), pygame.image.load('attackright.png')]
        if not (self.standing):
            if self.left:
                win.blit(wLeft, (self.playerposX, self.y))
            elif self.right:
                win.blit(wRight, (self.playerposX, self.y))
        else:
            if self.right:
                win.blit(char[0], (self.playerposX, self.y))
            if self.left:
                win.blit(char[1], (self.playerposX, self.y))
        if self.attacking == True:
            if self.left:
                win.blit(attack[0], (self.playerposX, self.y))
            if self.right:
                win.blit(attack[1], (self.playerposX, self.y))

我的目标是从父类（播放器）继承属性的子类相机。这是我将用来在玩家向前或向后移动时移动背景的代码

class camera(player):
    def __init__(self, stagePosX,playerposX,y):
        super(camera,self).__init__(playerposX,characterPosX,y)
        self.playerposX = playerposX
        self.startscrolling = bgWidth / 2
        self.stagePosX = stagePosX
        self.rel_x = 0


    def scroll(self,stagePosX):
        if self.k[pygame.K_LEFT]:
            self.vel = (self.vel*-1)
        elif self.k[pygame.K_RIGHT]:
            self.vel = (self.vel*1)
        else:
            self.vel = 0



        self.rel_x = self.stagePosX % bgWidth
        if self.playerPosX > stageWidth - self.width:
            self.playerPosX = self.stageWidth - self.width  # If the player position exceeds the stage
        if self.playerposX < 0 - self.width:
            self.playerposX = self.width  # If the player position is far left
        if self.playerposX < self.startscrolling:
            self.characterPosX = self.playerposX
        elif self.playerposXplayerposX > stageWidth - self.startscrolling:
            self.characterPosX = self.playerPosX - stageWidth + self.width
        else:
            self.characterPosX = self.startscrolling
            self.stagePosX +=  -self.vel






    def draw(self, win):
        win.blit(bg, (self.rel_x - bgWidth, 0))
        if self.rel_x < bgWidth:
            win.blit(bg, (self.rel_x, 0))

【问题讨论】：

如果你想调用player的__init__方法，你需要弄清楚你打算为characterPosX参数传递什么值。目前你只是在那个地方写characterPosX，一个在你试图使用它的上下文中不存在的变量。
是的，解释器是正确的（毫不奇怪），在表达式super(camera,self).__init__(playerposX,characterPosX,y) 中，变量characterPosX 没有在范围内的任何地方定义。你为什么期望它被定义？
我不明白我已经定义了不是吗？

标签： python python-3.x oop pygame

【解决方案1】：

我在这里冒险猜测，但对__init__() 的第二次调用正在传递尚不存在的参数。

def __init__(self, stagePosX,playerposX,y):
    super(camera,self).__init__(playerposX,characterPosX,y)

应该是这样的：

def __init__( self, stagePosX, playerposX, y):
    super( camera, self ).__init__( playerposX, stagePosX, y ) # NOT characterPosX

也许您需要为此发送不同或额外的参数？从问题的代码中很难知道。

【讨论】：