Eventos

Introducción

Events allow you to run functions in parallel by using event objects. Instead of calling functions or threads one after another, events let you register functions and then trigger them all at once. Each registered function runs in its own thread, so your robot can do multiple things—like blinking lights and driving—at the same time.

In order to create and then use an Event, follow these steps in order:

1. Create the event with Event.

2. Register a function to trigger when the Event is broadcast using event.

3. Broadcast an Event:

   • broadcast — Triggers all registered functions in an event object to run concurrently.

   • broadcast_and_wait — Triggers all registered functions in an event object and waits for them to finish before continuing.

Create an Event

Event creates an event object that manages function execution in separate threads.

Usage:
Event()

Parámetro	Descripción
	Este constructor no tiene parámetros.

# Blink the screen while moving forward
# Create move_event as an Event object
move_event = Event()

def blink_screen():
    while True:
        brain.screen.clear_screen(Color.RED)
        wait(0.5, SECONDS)
        brain.screen.clear_screen()
        wait(0.5, SECONDS)

move_event(blink_screen)
move_event.broadcast()
drivetrain.drive(FORWARD)

Registrar funciones en un evento

Cuando se registra una función en un evento, se ejecutará en un hilo separado cuando se transmita el evento.

Usage:
event(callback, args)

Parámetro	Descripción
event	El nombre del objeto de evento creado previamente.
callback	A function that is previously defined to execute when the event is broadcasted.
args	Opcional. Una tupla que contiene los argumentos que se pasarán a la función de devolución de llamada. Consulte Uso de funciones con parámetros para obtener más información.

# Blink the screen while turning
move_event = Event()

def blink_screen():
    while True:
        brain.screen.clear_screen(Color.RED)
        wait(0.5, SECONDS)
        brain.screen.clear_screen()
        wait(0.5, SECONDS)

def turning():
    drivetrain.turn(RIGHT)

# Register multiple functions to the Event object
move_event(blink_screen)
move_event(turning)

move_event.broadcast()

# Move in a specified direction
move_event = Event()

def move_distance(movement_angle):
    drivetrain.turn_for(RIGHT, movement_angle, DEGREES)
    drivetrain.drive_for(FORWARD, 100, MM)

# Change the parameter to modify how the robot moves
move_event(move_distance, (180,))
move_event.broadcast()

Broadcast an Event

broadcast

broadcast triggers an event, starting all registered functions in separate threads. This method does not pause execution of any subsequent functions.

Usage:
event.broadcast()

Parámetro	Descripción
event	El nombre del objeto de evento creado previamente.

# Blink the screen while moving forward
# Create move_event as an Event object
move_event = Event()

def blink_screen():
    while True:
        brain.screen.clear_screen(Color.RED)
        wait(0.5, SECONDS)
        brain.screen.clear_screen()
        wait(0.5, SECONDS)

move_event(blink_screen)
move_event.broadcast()
drivetrain.drive(FORWARD)

broadcast_and_wait

broadcast_and_wait starts an event but waits for all registered functions to finish before continuing with subsequent functions.

Usage:
event.broadcast_and_wait()

Parámetro	Descripción
event	El nombre del objeto de evento creado previamente.

# Move after the screen is pressed
move_event = Event()

def move_and_turn():
    drivetrain.drive_for(FORWARD, 150, MM)
    drivetrain.turn_for(RIGHT, 90)

move_event(move_and_turn)

while True:
    if brain.buttonCheck.pressing():
        move_event.broadcast_and_wait()
        break
brain.screen.print("Movement done.")