pygame移动用户控制的对象直到释放键？

Question

我玩 pygame 已经有一段时间了，stackoverflow 的老手给了我一些帮助，帮助我更好地改进代码以在屏幕上移动角色。每次按键时角色都会移动，减速然后停止，只有再次按键时才会继续移动。任何人都可以帮助角色在释放钥匙时减速并停止吗？

谢谢你

import sys
import pygame
import os
from pygame.locals import *

character = "toon.png"
bg = "bg.jpg"

delta = {
    pygame.K_LEFT: (-10, 0),
    pygame.K_RIGHT: (+10, 0),
    pygame.K_UP: (0, -10),
    pygame.K_DOWN: (0, +10),
    }

class Toon(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.image.load(character)
        self.bg = pygame.image.load(bg)
        self.rect = self.image.get_rect()
        self.speed = [2, 2]
        self.area = pygame.display.get_surface().get_rect()
    def update(self):
        self.rect = self.rect.move(self.speed)
        if self.rect.left < 0 or self.rect.right > self.area.width:
            self.speed[0] = -self.speed[0]
        if self.rect.top < 0 or self.rect.bottom > self.area.height:
            self.speed[1] = -self.speed[1]

class Main(object):
    def __init__(self):
        self.setup()
    def setup(self):
        pygame.init()
        size = (self.width, self.height) = (640,360)
        self.black = (0, 0, 0)
        self.bg = pygame.image.load(bg)
        self.screen = pygame.display.set_mode(size, 0, 32)
        self.toon = Toon()
        self.setup_background()
    def setup_background(self):
        self.background = pygame.Surface(self.screen.get_size())
        self.background = self.background.convert()
        self.screen.blit(self.bg, (0, 0))
        pygame.display.flip()
    def draw(self):
        self.screen.blit(self.bg, (0, 0))
        self.screen.blit(self.toon.image, self.toon.rect)
        pygame.display.flip()
    def event_loop(self):
        toon = self.toon
        while True:
            for event in pygame.event.get():
                if event.type == QUIT:
                    pygame.quit()
                    sys.exit()
                elif event.type == pygame.KEYDOWN:
                    deltax, deltay = delta.get(event.key, (0, 0))
                    toon.speed[0] += deltax
                    toon.speed[1] += deltay
            toon.speed[0] *= 0.95
            toon.speed[1] *= 0.95
            toon.update()
            self.draw()
            pygame.time.delay(10)

if __name__ == '__main__':
    app = Main()
    app.event_loop()

Answer 1

我只想更改您的 Main.event_loop() 并将另一个函数添加到您的主类，它使用 pygame.key.get_pressed：

def event_loop(self):
    toon = self.toon
    while True:
        self.event_handle()
        toon.speed[0] *= 0.95
        toon.speed[1] *= 0.95
        toon.update()
        self.draw()
        pygame.time.delay(10)

def event_handle(self):
    for event in pygame.event.get():
        if event.type == QUIT:
            pygame.quit()
            sys.exit()
    # This will allow diagonal movements.. 
    key = pygame.key.get_pressed()
    if key[pygame.K_LEFT]:
        self.toon.speed[0] = -10
    if key[pygame.K_RIGHT]:
        self.toon.speed[0] = +10
    if key[pygame.K_UP]:
        self.toon.speed[1] = -10
    if key[pygame.K_DOWN]:
        self.toon.speed[1] = +10

变化：

1. 我添加了一个新函数，即event_handle，它将处理事件和键。
2. 您会注意到 for 事件循环不进行任何键处理。那是因为我们使用的是更适合当前工作的pygame.key.get_pressed。
   
   • 它返回当前按下的键的布尔值列表。我们通过索引key 来检查我们想要的键（这里的箭头）。

效果：
你的问题解决了。

Answer 2

在KEYDOWN 时创建friction = 1，在KEYUP 时创建friction < 1：

            elif event.type == pygame.KEYDOWN:
                deltax, deltay = delta.get(event.key, (0, 0))
                toon.speed[0] += deltax
                toon.speed[1] += deltay
                friction = 1
            elif event.type == pygame.KEYUP:
                friction = 0.95
        toon.speed = [x*friction for x in toon.speed]

---

import sys
import pygame
import os
from pygame.locals import *

character = "toon.png"
bg = "bg.jpg"

delta = {
    pygame.K_LEFT: (-10, 0),
    pygame.K_RIGHT: (+10, 0),
    pygame.K_UP: (0, -10),
    pygame.K_DOWN: (0, +10),
    }

class Toon(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.image.load(character)
        self.bg = pygame.image.load(bg)
        self.rect = self.image.get_rect()
        self.speed = [0, 0]
        self.area = pygame.display.get_surface().get_rect()
    def update(self):
        self.rect = self.rect.move(self.speed)
        if self.rect.left < 0 or self.rect.right > self.area.width:
            self.speed[0] = -self.speed[0]
        if self.rect.top < 0 or self.rect.bottom > self.area.height:
            self.speed[1] = -self.speed[1]

class Main(object):
    def __init__(self):
        self.setup()
    def setup(self):
        pygame.init()
        size = (self.width, self.height) = (640,360)
        self.black = (0, 0, 0)
        self.bg = pygame.image.load(bg)
        self.screen = pygame.display.set_mode(size, 0, 32)
        self.toon = Toon()
        self.setup_background()
    def setup_background(self):
        self.background = pygame.Surface(self.screen.get_size())
        self.background = self.background.convert()
        self.screen.blit(self.bg, (0, 0))
        pygame.display.flip()
    def draw(self):
        self.screen.blit(self.bg, (0, 0))
        self.screen.blit(self.toon.image, self.toon.rect)
        pygame.display.flip()
    def event_loop(self):
        toon = self.toon
        friction = 1        
        while True:
            for event in pygame.event.get():
                if event.type == QUIT:
                    pygame.quit()
                    sys.exit()
                elif event.type == pygame.KEYDOWN:
                    deltax, deltay = delta.get(event.key, (0, 0))
                    toon.speed[0] += deltax
                    toon.speed[1] += deltay
                    friction = 1
                elif event.type == pygame.KEYUP:
                    friction = 0.95
            toon.speed = [x*friction for x in toon.speed]
            toon.update()
            self.draw()
            pygame.time.delay(10)

if __name__ == '__main__':
    app = Main()
    app.event_loop()