// START SNIPPET: listen-multi-gpio-snippet
/*
* #%L
* **********************************************************************
* ORGANIZATION : Pi4J
* PROJECT : Pi4J :: Java Examples
* FILENAME : ListenMultipleGpioExample.java
*
* This file is part of the Pi4J project. More information about
* this project can be found here: http://www.pi4j.com/
* **********************************************************************
* %%
* Copyright (C) 2012 - 2013 Pi4J
* %%
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* #L%
*/
import com.pi4j.io.gpio.GpioController;
import com.pi4j.io.gpio.GpioFactory;
import com.pi4j.io.gpio.GpioPinDigitalInput;
import com.pi4j.io.gpio.PinPullResistance;
import com.pi4j.io.gpio.RaspiPin;
import com.pi4j.io.gpio.event.GpioPinDigitalStateChangeEvent;
import com.pi4j.io.gpio.event.GpioPinListenerDigital;
/**
* This example code demonstrates how to setup a listener
* for GPIO pin state changes on the Raspberry Pi.
*
* @author Robert Savage
*/
public class ListenMultipleGpioExample {
public static void main(String args[]) throws InterruptedException {
System.out.println("<--Pi4J--> GPIO Listen Example ... started.");
// create GPIO controller
final GpioController gpio = GpioFactory.getInstance();
// create GPIO listener
GpioPinListenerDigital listener = new GpioPinListenerDigital() {
@Override
public void handleGpioPinDigitalStateChangeEvent(GpioPinDigitalStateChangeEvent event) {
// display pin state on console
System.out.println(" --> GPIO PIN STATE CHANGE: " + event.getPin() + " = " + event.getState());
}
};
// provision gpio input pins with its internal pull down resistor enabled
GpioPinDigitalInput[] pins = {
gpio.provisionDigitalInputPin(RaspiPin.GPIO_00, PinPullResistance.PULL_DOWN),
gpio.provisionDigitalInputPin(RaspiPin.GPIO_01, PinPullResistance.PULL_DOWN),
gpio.provisionDigitalInputPin(RaspiPin.GPIO_02, PinPullResistance.PULL_DOWN),
gpio.provisionDigitalInputPin(RaspiPin.GPIO_03, PinPullResistance.PULL_DOWN),
gpio.provisionDigitalInputPin(RaspiPin.GPIO_04, PinPullResistance.PULL_DOWN),
gpio.provisionDigitalInputPin(RaspiPin.GPIO_05, PinPullResistance.PULL_DOWN),
gpio.provisionDigitalInputPin(RaspiPin.GPIO_06, PinPullResistance.PULL_DOWN),
gpio.provisionDigitalInputPin(RaspiPin.GPIO_07, PinPullResistance.PULL_DOWN)
};
// create and register gpio pin listener
gpio.addListener(listener, pins);
System.out.println(" ... complete the GPIO #02 circuit and see the listener feedback here in the console.");
// keep program running until user aborts (CTRL-C)
for (;;) {
Thread.sleep(500);
}
// stop all GPIO activity/threads by shutting down the GPIO controller
// (this method will forcefully shutdown all GPIO monitoring threads and scheduled tasks)
// gpio.shutdown(); <--- implement this method call if you wish to terminate the Pi4J GPIO controller
}
}
// END SNIPPET: listen-multi-gpio-snippet