为什么模块在引擎代码中看不到类？

Question

我在这里写一个小游戏。我已经在 .py 文件中描述了游戏场景，以将它们作为模块导入，以使代码更清晰。 我还尝试将场景定义放入单独的 .py 文件中，并将其作为模块导入这些模块中，甚至将其与引擎代码中的模块一起导入。错误是一样的：

Traceback (most recent call last):
  File "engine_chapter_1.py", line 4, i
    import module_intro
  File "C:\Users\r.hrytskiv\Documents\P
    class Intro(Scene):
NameError: name 'Scene' is not defined

这是引擎代码本身：

from sys import exit
from random import randint

import module_intro
import module_house_one
import module_package_zoom
import module_house_two
import module_unboxing
import module_key_letter
import module_letter_key
import module_house_three

class Scene(object):

    def enter(self):
        print "Subclass and implement"
        exit(1)

class EndGame(Scene):

    cast = [
            "Roman Hrytskiv"
            "Dmytro Litvyn"
    ]

    def enter(self):
        print EndGame.cast
        exit(1)

class Engine(object):

    def __init__(self, scene_map):
        self.scene_map = scene_map

    def play(self):
        current_scene = self.scene_map.opening_scene()
        last_scene = self.scene_map.next_scene('finished')

        while current_scene != last_scene:
            next_scene_name = current_scene.enter()
            current_scene = self.scene_map.next_scene(next_scene_name)

        current_scene.enter()

class Map(object):

    scenes = {
    'intro': Intro(),
    'house_one': HouseOne(),
    'package_zoom': PackageZoom(),
    'house_two': HouseTwo(),
    'unboxing': Unboxing(),
    'key_letter': KeyLetter(),
    'letter_key': LetterKey(),
    'house_three': HouseThree(),
    'end_game': EndGame()
    }

    def __init__(self, start_scene):
        self.start_scene = start_scene

    def next_scene(self, scene_name):
        val = Map.scenes.get(scene_name)
        return val

    def opening_scene(self):
        return self.next_scene(self.start_scene)

    a_map = Map('intro')
    a_game = Engine(a_map)
    a_game.play()

其中一个模块：

class Intro(Scene):

def enter(self):
    print "City of Bend, OR. Morning. Nowadays."
    print "City panorama, people on the streets, around noon."
    print "Roland is the hero of this story. He is 27 years old guy."
    print "He has recently left University. He's always looking for"
    print "something interesting and fun. Doesn't like to sit in one place."
    print "For now he's unemployed and struggling to pay for rent so"
    print "he decided to sell some stuff from his house. He went to the"
    print "attic to check if there is something he might sell."
    print "He found some antique stuff and went to pawn shop..."
    return 'house_one'

更新 1

新引擎代码：

from sys import exit

从随机导入randint

导入模块介绍 导入模块_house_one 导入 module_package_zoom 导入模块_house_two 导入模块_拆箱 导入 module_key_letter 导入模块字母键 导入 module_house_three 导入模块_end_game

类引擎（对象）：

def __init__(self, scene_map):
    self.scene_map = scene_map

def play(self):
    current_scene = self.scene_map.opening_scene()
    last_scene = self.scene_map.next_scene('finished')

    while current_scene != last_scene:
        next_scene_name = current_scene.enter()
        current_scene = self.scene_map.next_scene(next_scene_name)

    current_scene.enter()

类映射（对象）：

scenes = {
'intro': Intro(),
'house_one': HouseOne(),
'package_zoom': PackageZoom(),
'house_two': HouseTwo(),
'unboxing': Unboxing(),
'key_letter': KeyLetter(),
'letter_key': LetterKey(),
'house_three': HouseThree(),
'end_game': EndGame()
}

def __init__(self, start_scene):
    self.start_scene = start_scene

def next_scene(self, scene_name):
    val = Map.scenes.get(scene_name)
    return val

def opening_scene(self):
    return self.next_scene(self.start_scene)

a_map = Map('intro')
a_game = Engine(a_map)
a_game.play()

新模块代码：

import module_scene

类介绍（module_scene.Scene）：

def enter(self):
    print "City of Bend, OR. Morning. Nowadays."
    print "City panorama, people on the streets, around noon."
    print "Roland is the hero of this story. He is 27 years old guy."
    print "He has recently left University. He's always looking for"
    print "something interesting and fun. Doesn't like to sit in one place."
    print "For now he's unemployed and struggling to pay for rent so"
    print "he decided to sell some stuff from his house. He went to the"
    print "attic to check if there is something he might sell."
    print "He found some antique stuff and went to pawn shop..."
    return 'house_one'

灵魂： 只需通过 package_name 引用它们。

scenes = {
'intro': module_intro.Intro(),
'house_one': module_house_one.HouseOne(),
'package_zoom': module_package_zoom.PackageZoom(),
'house_two': module_house_two.HouseTwo(),
'unboxing': module_unboxing.Unboxing(),
'key_letter': module_key_letter.KeyLetter(),
'letter_key': module_letter_key.LetterKey(),
'house_three': module_house_three.HouseThree(),
'end_game': module_end_game.EndGame()
}

Answer 1

首先，您应该将Scene 类移动到其他文件/包中。

要在您的 module_intro 中使用它，您必须通过以下方式将其导入：

 from package_name import Scene

或：

import package_name

（但随后将场景用作package_name.Scene）

在主项目文件中保留Scene 实现将导致创建循环引用（两个模块相互导入）