Just some ideas for the custom button & joystick event listener

src/control/Button.java

@@ -0,0 +1,16 @@
+package control;
+
+import com.pi4j.io.gpio.GpioFactory;
+import com.pi4j.io.gpio.GpioPinDigitalInput;
+import com.pi4j.io.gpio.Pin;
+
+public class Button {
+	private GpioPinDigitalInput input;
+	
+	public Button(int buttonId, Pin pin){
+		input = GpioFactory.getInstance().provisionDigitalInputPin(pin , "Button:"+buttonId);
+	}
+	public boolean getState(){
+		return input.getState().isLow();
+	}
+}