Eventos

Introducción

Los eventos permiten ejecutar funciones en paralelo mediante objetos de evento. En lugar de llamar a las funciones secuencialmente, los eventos permiten registrarlas y activarlas todas a la vez. Cada función registrada se ejecuta en su propio hilo, lo que permite que el robot realice varias acciones simultáneamente, como hacer parpadear los LED y conducir.

A continuación se muestra una lista de métodos y constructores disponibles:

• event – Creates a new event object.

• Register Functions to an Event – Registers a function to the event object.

• broadcast – Triggers all registered functions in an event object to run in parallel.

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

Create an Event Object

The event constructor is used to create an event object that manages function execution in separate threads.

Usage:
event(callback);

Parámetro	Descripción
callback	Opcional. Una función que se define previamente para ejecutarse cuando se transmite el evento.

// Blink the screen while moving forward
// Create moveEvent as an event object
event moveEvent = event();

void blinkScreen() {
  while (true) {
    Brain.Screen.clearScreen(red);
    wait(0.5, seconds);
    Brain.Screen.clearScreen();
    wait(0.5, seconds);
  }
}

int main() {
  // Initializing Robot Configuration. DO NOT REMOVE!
  vexcodeInit();
  // Begin project code
  moveEvent(blinkScreen);
  moveEvent.broadcast();
  Drivetrain.drive(forward);
}

// Blink the screen while moving forward
// Create moveEvent as an event object
void blinkScreen() {
  while (true) {
    Brain.Screen.clearScreen(red);
    wait(0.5, seconds);
    Brain.Screen.clearScreen();
    wait(0.5, seconds);
  }
}

int main() {
  // Initializing Robot Configuration. DO NOT REMOVE!
  vexcodeInit();
  // Begin project code
  event moveEvent = event(blinkScreen);
  moveEvent.broadcast();
  Drivetrain.drive(forward);
}

Register Functions to an Event

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

Usage:
eventName(callback);

Parámetro	Descripción
eventName	El nombre del objeto de evento creado previamente.
callback	Una función que se define previamente para ejecutarse cuando se transmite el evento.

// Blink the screen while turning
event moveEvent = event();

void blinkScreen() {
  while (true) {
    Brain.Screen.clearScreen(red);
    wait(0.5, seconds);
    Brain.Screen.clearScreen();
    wait(0.5, seconds);
  }
}

void turning() {
  Drivetrain.turn(right);
}
int main() {
  // Initializing Robot Configuration. DO NOT REMOVE!
  vexcodeInit();
  // Register multiple functions to the event object
  moveEvent(blinkScreen);
  moveEvent(turning);

  moveEvent.broadcast();
}

broadcast

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

Usage:
myEvent.broadcast();

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

// Blink the screen while moving forward
// Create moveEvent as an event object
event moveEvent = event();

void blinkScreen() {
  while (true) {
    Brain.Screen.clearScreen(red);
    wait(0.5, seconds);
    Brain.Screen.clearScreen();
    wait(0.5, seconds);
  }
}

int main() {
  // Initializing Robot Configuration. DO NOT REMOVE!
  vexcodeInit();
  // Begin project code
  moveEvent(blinkScreen);
  moveEvent.broadcast();
  Drivetrain.drive(forward);
}

broadcastAndWait

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

Usage:
myEvent.broadcastAndWait();

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

// Move after the left button is pressed
event moveEvent = event();

void moveAndTurn() {
  Drivetrain.driveFor(forward, 150, mm);
  Drivetrain.turnFor(right, 90, degrees);
}

int main() {
  // Initializing Robot Configuration. DO NOT REMOVE!
  vexcodeInit();
  // Begin project code
  moveEvent(moveAndTurn);
  while (true) {
    if (Brain.buttonLeft.pressing()) {
      moveEvent.broadcastAndWait();
      break;
    }
    wait(20, msec);
  }
  Brain.Screen.print("Movement done.");
}