Drag multiple sprites with different “update ()” methods from the same Sprite class in Pygame

Question

I recommend to create a class DragOperator which can drag an pygame.Rect object:

class DragOperator:
    def __init__(self, sprite):
        self.sprite = sprite
        self.dragging = False
        self.rel_pos = (0, 0)
    def update(self, event_list):
        for event in event_list:
            if event.type == pygame.MOUSEBUTTONDOWN:
                self.dragging = self.sprite.rect.collidepoint(event.pos)
                self.rel_pos = event.pos[0] - self.sprite.rect.x, event.pos[1] - self.sprite.rect.y
            if event.type == pygame.MOUSEBUTTONUP:
                self.dragging = False
            if event.type == pygame.MOUSEMOTION and self.dragging:
                self.sprite.rect.topleft = event.pos[0] - self.rel_pos[0], event.pos[1] - self.rel_pos[1]

The dragging of the rectangle is implemented in the update method. Use this class in a pygame.sprite.Sprite object. Pass the list of events to the update method of the Sprite and delegate it to the drag operator:

class animatedSprites(pygame.sprite.Sprite):
    def __init__(self, spriteName):
        # [...]

        self.drag = DragOperator(self)

    def update(self, event_list):
        self.drag.update(event_list)

Pass the list of event form the main application loop to the pygame.sprite.Group:

all_sprites = pygame.sprite.Group()
all_sprites.add(animatedSprites("my_sprite"))

run = True
while run:
    event_list = pygame.event.get()
    for event in event_list:
        if event.type == pygame.QUIT:
            run = False

    all_sprites.update(event_list)

    # [...]

Minmal example: repl.it/@Rabbid76/PyGame-MouseDrag

import pygame

class DragOperator:
    def __init__(self, sprite):
        self.sprite = sprite
        self.dragging = False
        self.rel_pos = (0, 0)
    def update(self, event_list):
        for event in event_list:
            if event.type == pygame.MOUSEBUTTONDOWN:
                self.dragging = self.sprite.rect.collidepoint(event.pos)
                self.rel_pos = event.pos[0] - self.sprite.rect.x, event.pos[1] - self.sprite.rect.y
            if event.type == pygame.MOUSEBUTTONUP:
                self.dragging = False
            if event.type == pygame.MOUSEMOTION and self.dragging:
                self.sprite.rect.topleft = event.pos[0] - self.rel_pos[0], event.pos[1] - self.rel_pos[1]

class SpriteObject(pygame.sprite.Sprite):
    def __init__(self, x, y, color):
        super().__init__() 
        self.original_image = pygame.Surface((50, 50), pygame.SRCALPHA)
        pygame.draw.circle(self.original_image, color, (25, 25), 25)
        self.drag_image = pygame.Surface((50, 50), pygame.SRCALPHA)
        pygame.draw.circle(self.drag_image, color, (25, 25), 25)
        pygame.draw.circle(self.drag_image, (255, 255, 255), (25, 25), 25, 4)
        self.image = self.original_image 
        self.rect = self.image.get_rect(center = (x, y))
        self.drag = DragOperator(self)
    def update(self, event_list):
        self.drag.update(event_list) 
        self.image = self.drag_image if self.drag.dragging else self.original_image

pygame.init()
window = pygame.display.set_mode((300, 300))
clock = pygame.time.Clock()

sprite_object = SpriteObject(*window.get_rect().center, (255, 255, 0))
group = pygame.sprite.Group([
    SpriteObject(window.get_width() // 3, window.get_height() // 3, (255, 0, 0)),
    SpriteObject(window.get_width() * 2 // 3, window.get_height() // 3, (0, 255, 0)),
    SpriteObject(window.get_width() // 3, window.get_height() * 2 // 3, (0, 0, 255)),
    SpriteObject(window.get_width() * 2// 3, window.get_height() * 2 // 3, (255, 255, 0)),
])

run = True
while run:
    clock.tick(60)
    event_list = pygame.event.get()
    for event in event_list:
        if event.type == pygame.QUIT:
            run = False

    group.update(event_list)

    window.fill(0)
    group.draw(window)
    pygame.display.flip()

pygame.quit()
exit()

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