Triggers and RangeTriggers

Checking gamepad1.a yourself means tracking last loop’s value to catch the press, then deciding when to schedule and when to cancel. Triggers do that bookkeeping. Bind a command once, and NextFTC polls the condition and schedules or cancels for you every loop.

The examples use a driver of type CommandGamepad, which wraps an FTC Gamepad and exposes every button as a Trigger and every stick and analog trigger as a RangeTrigger. Build one in your OpMode’s start():

Kotlin

val driver = CommandGamepad(gamepad1)

Java

CommandGamepad driver = new CommandGamepad(gamepad1);

Trigger

A Trigger is a boolean condition plus the methods that bind a command to how that condition changes:

Method	Schedules the command when…	Cancels it when…
onTrue	condition goes false to true	never
onFalse	condition goes true to false	never
onChange	condition changes in either direction	never
whileTrue	condition goes false to true	it goes back to false
whileFalse	condition goes true to false	it goes back to true
toggleOnTrue	condition goes false to true and the command isn’t running	the same edge, if it is
toggleOnFalse	condition goes true to false and the command isn’t running	the same edge, if it is

Kotlin

driver.a.onTrue(claw.close())
driver.b.whileTrue(intake.run())

Java

driver.a().onTrue(claw.close());
driver.b().whileTrue(intake.run());

Every one of these returns the trigger, so you can bind more than one command to the same button.

Combine triggers with and, or, and negate. debounce(seconds) requires the condition to hold that long before it counts, which filters out a flaky switch or a bumped button. multiPress(requiredPresses, windowTime) waits for that many presses inside the window, so multiPress(2, 0.5) is a double-press.

Kotlin

driver.a.and(driver.rightBumper).onTrue(climb.start())

Java

driver.a().and(driver.rightBumper()).onTrue(climb.start());

RangeTrigger

A RangeTrigger holds an analog value, either a stick axis or an analog trigger. Read value for the raw number, or turn a threshold into a Trigger:

Method	Active when…
isOver(threshold)	value is greater than threshold
isUnder(threshold)	value is less than threshold
isBetween(lower, upper)	value is within [lower, upper]

Kotlin

driver.rightTrigger.isOver(0.5).onTrue(intake.run())

val rawValue = driver.leftStickY.value

Java

driver.rightTrigger().isOver(0.5).onTrue(intake.run());

double rawValue = driver.leftStickY().getValue();

isOver, isUnder, and isBetween all return an ordinary Trigger, so every binding method in the table above works on the result, along with and, or, debounce, and the rest.