AttributeError：類實例沒有__call__方法

Question

我對python有點新，但熟悉OOP。 我正在嘗試使用PyGame編寫游戲。 基本上，我的目標是每隔幾秒鍾渲染一次樹木，並將樹木移動到整個屏幕上。

所以這是我的代碼：

from collections import deque
import pygame,random,sys

pygame.init()
size = 800,600
screen = pygame.display.set_mode(size)

class tree:
    def __init__(self):
            self.img = pygame.image.load("tree.png")
            self.rect = self.img.get_rect()
    def render(self):
            screen.blit(self.img,self.rect)
    def move(self,x,y):
            self.rect = self.rect.move(x,y)

#creating a queue of trees
trees = deque()

#appending the first tree on to the queue 
trees.append(tree())


while 1:


    for event in pygame.event.get():
            if event.type == pygame.QUIT: sys.exit()

    #appending tree() to trees queue every 300 ms
    if pygame.time.get_ticks() % 300 == 0:
            trees.append(tree())

    #rendering and moving all the tree rects of trees in the queue
    for tree in trees:
            tree.render()
            tree.move(20,2)
    pygame.display.flip()

但是當我執行它時，前幾個樹成功生成，但PyGame窗口關閉，我收到此錯誤：

Traceback (most recent call last):
File "error.py", line 25, in <module>
trees.append(tree())
AttributeError: tree instance has no __call__ method

Answer 1

我想這是因為你有一個變量名tree （在tree.render() ），它與你的類名沖突。 稱之為Tree會更好（而且更加pythonic ^^）。

Answer 2

您可能希望在for循環中調用tree變量而不是tree 。 它正在影響班級名稱。

Answer 3

你的背景受到污染

while 1:
    for event in pygame.event.get():
        if event.type == pygame.QUIT: sys.exit()

    #appending tree() to trees queue every 300 ms
    if pygame.time.get_ticks() % 300 == 0:
        trees.append(tree()) <----------------------- second time, this tree is not your class, but the last instance of tree

    #rendering and moving all the tree rects of trees in the queue
    for tree in trees: <-------------------- here, the last tree will get name with tree
        tree.render()
        tree.move(20,2) 
    pygame.display.flip()

編譯器可能認為您不是初始化類，而是調用其調用函數。