Package edu.wpi.first.wpilibj2.command.button

Class Trigger

java.lang.Object
edu.wpi.first.wpilibj2.command.button.Trigger
All Implemented Interfaces:
BooleanSupplier
Direct Known Subclasses:
InternalButton, JoystickButton, NetworkButton, POVButton
public class Trigger
extends Object
implements BooleanSupplier
This class provides an easy way to link commands to conditions.

It is very easy to link a button to a command. For instance, you could link the trigger button of a joystick to a "score" command.

Triggers can easily be composed for advanced functionality using the and(BooleanSupplier), or(BooleanSupplier), negate() operators.

This class is provided by the NewCommands VendorDep

  • Constructor Details

    • Trigger

      public Trigger​(EventLoop loop, BooleanSupplier condition)
      Creates a new trigger based on the given condition.
      Parameters:
      loop - The loop instance that polls this trigger.
      condition - the condition represented by this trigger

    • Trigger

      public Trigger​(BooleanSupplier condition)
      Creates a new trigger based on the given condition.

      Polled by the default scheduler button loop.

      Parameters:
      condition - the condition represented by this trigger

  • Method Details

    • onTrue

      public Trigger onTrue​(Command command)
      Starts the given command whenever the condition changes from `false` to `true`.
      Parameters:
      command - the command to start
      Returns:
      this trigger, so calls can be chained

    • onFalse

      public Trigger onFalse​(Command command)
      Starts the given command whenever the condition changes from `true` to `false`.
      Parameters:
      command - the command to start
      Returns:
      this trigger, so calls can be chained

    • whileTrue

      public Trigger whileTrue​(Command command)
      Starts the given command when the condition changes to `true` and cancels it when the condition changes to `false`.

      Doesn't re-start the command if it ends while the condition is still `true`. If the command should restart, see RepeatCommand.

      Parameters:
      command - the command to start
      Returns:
      this trigger, so calls can be chained

    • whileFalse

      public Trigger whileFalse​(Command command)
      Starts the given command when the condition changes to `false` and cancels it when the condition changes to `true`.

      Doesn't re-start the command if it ends while the condition is still `false`. If the command should restart, see RepeatCommand.

      Parameters:
      command - the command to start
      Returns:
      this trigger, so calls can be chained

    • toggleOnTrue

      public Trigger toggleOnTrue​(Command command)
      Toggles a command when the condition changes from `false` to `true`.
      Parameters:
      command - the command to toggle
      Returns:
      this trigger, so calls can be chained

    • toggleOnFalse

      public Trigger toggleOnFalse​(Command command)
      Toggles a command when the condition changes from `true` to `false`.
      Parameters:
      command - the command to toggle
      Returns:
      this trigger, so calls can be chained

    • getAsBoolean

      public boolean getAsBoolean()
      Specified by:
      getAsBoolean in interface BooleanSupplier

    • and

      public Trigger and​(BooleanSupplier trigger)
      Composes two triggers with logical AND.
      Parameters:
      trigger - the condition to compose with
      Returns:
      A trigger which is active when both component triggers are active.

    • or

      public Trigger or​(BooleanSupplier trigger)
      Composes two triggers with logical OR.
      Parameters:
      trigger - the condition to compose with
      Returns:
      A trigger which is active when either component trigger is active.

    • negate

      public Trigger negate()
      Creates a new trigger that is active when this trigger is inactive, i.e. that acts as the negation of this trigger.
      Returns:
      the negated trigger

    • debounce

      public Trigger debounce​(double seconds)
      Creates a new debounced trigger from this trigger - it will become active when this trigger has been active for longer than the specified period.
      Parameters:
      seconds - The debounce period.
      Returns:
      The debounced trigger (rising edges debounced only)

    • debounce

      public Trigger debounce​(double seconds, Debouncer.DebounceType type)
      Creates a new debounced trigger from this trigger - it will become active when this trigger has been active for longer than the specified period.
      Parameters:
      seconds - The debounce period.
      type - The debounce type.
      Returns:
      The debounced trigger.