python中的冲突错误[pygame]

Question

import pygame, sys
from pygame.locals import *



#Game mechanics that dosent fit into a class


global collide
collide = False
def checkCollision(players, blocks):
    for player in players:
        ox = player.x
        oy = player.y
        for block in blocks:
            if player.rect.colliderect(block.rect):
                print "collide"
                player.movePlayer(ox, oy)
                collide = True
# The class that controls the game      
class Game:
    def __init__(self):
        self.earth = World("Earth", 0.3)
        self.PlayerEntities = [Player(10,10)]


    #Method that starts the game    
    def init_game(self):
        jumpc = 0
        global screen
        pygame.init()
        screen = pygame.display.set_mode((800,500))
        pygame.display.set_caption(self.earth.returnName())
        moveDown = False
        moveUp = False
        moveLeft = False
        moveRight = False
        tickCounter = 0
        while True:
            screen.fill((200,200,255))
            self.earth.drawWorld()
            #print tickCounter
            #print self.PlayerEntities[0].x, self.PlayerEntities[0].y
            checkCollision(self.PlayerEntities, self.earth.returnBlocks())
            for player in self.PlayerEntities:
                player.drawPlayer()

            #Game mechanic checkers go here:
            for players in self.PlayerEntities:
                self.earth.gravityMove(players, moveUp)
            #Movement has to go here for it to be smooth, sadly.

            #Keypress
            for event in pygame.event.get():
                #Pushing the key
                if event.type == QUIT:
                    pygame.quit()
                    sys.exit()
                if event.type == pygame.KEYDOWN:
                    if event.key == K_DOWN:
                        moveDown = True
                    if event.key == K_UP:
                        moveUp = True
                        jumpc = tickCounter
                    if event.key == K_LEFT:
                        moveLeft = True
                    if event.key == K_RIGHT:
                        moveRight = True

                #Releasing the key
                if event.type == pygame.KEYUP:
                    if event.key == K_DOWN:
                        moveDown = False
                    if event.key == K_UP:
                        moveUp = False
                    if event.key == K_LEFT:
                        moveLeft = False
                    if event.key == K_RIGHT:
                        moveRight = False                       
            #Moving
            if moveDown == True:
                self.PlayerEntities[0].movePlayer(0,0.5)
            if moveUp == True:
                self.PlayerEntities[0].movePlayer(0,-0.5)
            if tickCounter == jumpc + 100:
                    moveUp = False
            if moveLeft == True:
                self.PlayerEntities[0].movePlayer(-0.3, 0)
            if moveRight == True:
                self.PlayerEntities[0].movePlayer(0.3, 0)


            pygame.display.flip()
            tickCounter += 1
    def returnScreen(self):
        return screen

# The player class
class Player:
    # Initializing the position and the looks of the player class.
    def __init__(self, x, y):
        self.x = x
        self.y = y
        self.rect = pygame.Rect((self.x, self.y), (self.x+10, self.y+20))

    def drawPlayer(self):

        pygame.draw.rect(screen, (255,0,0), (self.x,self.y,10,20),1)
    def movePlayer(self, nx, ny):

        self.x = self.x + nx
        self.y = self.y + ny
        self.rect.move_ip(self.x, self.y)

# For diffrent textures
class Textures:
    def __init__(self):
        self.BlockTextures = {"DIRT":(0,255,0)}

    def returnTexture(self, type):
        return self.BlockTextures["DIRT"]



#World class
class World(Game):
    def __init__(self, name, gravity):
        self.blocks = [Block("DIRT",10, 50),Block("DIRT",20, 50),Block("DIRT",50, 50)]
        self.name = name
        self.maxGravity = gravity
        self.gravmodify = gravity

    def returnName(self):
        return self.name

    def drawWorld(self):
        for block in self.blocks:
            block.drawBlock()

    def returnBlocks(self):
        return self.blocks

    def gravityMove(self, player, moveUp):
        if collide == False:
            if moveUp == False:
                if player.y < 500:
                    player.movePlayer(0, self.maxGravity-self.gravmodify)
                    self.gravmodify = self.gravmodify - 0.004
            if moveUp == True:
                self.gravmodify = self.maxGravity

# block class
class Block(World):
    def __init__(self, type, x, y):
        self.x = x
        self.type = type
        self.y = y
        self.rect = pygame.Rect((self.x, self.y), (self.x+10, self.y+10))
    def drawBlock(self):
        pygame.draw.rect(screen, Texture.returnTexture(self.type),(self.x,self.y,10,10), 1)



# Debugging and testing for the API
Texture = Textures()
mainGame = Game()
mainGame.init_game()

我已经尝试了3种不同的方法来制作这个游戏的碰撞。他们两个都不行。这一次，它只是不断地从积木中跌落，即使打印出“碰撞”，它也没有像应该的那样停止

我很乐意帮忙，谢谢