Gist which shows how to handle button events with callback method and peripheral manager (Kotlin, Android Things)

Button events with peripheral manager.kt

package <package_name>

import android.app.Activity
import android.os.Bundle
import android.util.Log
import com.google.android.things.pio.Gpio
import com.google.android.things.pio.GpioCallback
import com.google.android.things.pio.PeripheralManager
import java.io.IOException

class ButtonEvents : Activity() {

    //Variables
    val TAG = "Button Events Activity"
    val BUTTON_PIN_NAME = <pin_name>
    val manager = PeripheralManager.getInstance()
    lateinit var mButtonGpio: Gpio

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        try {
            // Create GPIO connection.
            mButtonGpio = manager.openGpio(BUTTON_PIN_NAME)
            // Configure as an input.
            mButtonGpio.setDirection(Gpio.DIRECTION_IN)
            // Enable edge trigger events.
            mButtonGpio.setEdgeTriggerType(Gpio.EDGE_FALLING)
            // Register an event callback.
            mButtonGpio.registerGpioCallback(mCallBack)
        } catch (e: IOException) {
            Log.e(TAG, "Error on PeripheralIO API", e)
        }
    }

    override fun onDestroy() {
        super.onDestroy()
        mButtonGpio.unregisterGpioCallback(mCallBack)
        // Close the resource
        try {
            mButtonGpio.close()
        } catch (e: IOException) {
            Log.e(TAG, "Error on Peripheral IO API", e)
        }

    }

    // Register an event callback.
    private val mCallBack = GpioCallback {
        Log.i(TAG, "GPIO state changed, button pressed")
        // Return true to keep callback active.
        true
    }
}