lejos.nxt
Class Button

java.lang.Object
  extended by lejos.nxt.Button
All Implemented Interfaces:
ListenerCaller

public class Button
extends Object
implements ListenerCaller

Abstraction for an NXT button. Example:

    Button.ENTER.waitForPressAndRelease();
    Sound.playTone (1000, 1);
 


Field Summary
static Button[] BUTTONS
          Array containing ENTER, LEFT, RIGHT, ESCAPE, in that order.
static Button ENTER
          The Enter button.
static Button ESCAPE
          The Escape button.
static Button LEFT
          The Left button.
static Button RIGHT
          The Right button.
 
Method Summary
 void addButtonListener(ButtonListener aListener)
          Adds a listener of button events.
 void callListeners()
          Call Button Listeners.
 int getId()
          Return the ID of the button.
 boolean isPressed()
          Check if the button is pressed.
static int readButtons()
          Low-level API that reads status of buttons.
 void waitForPressAndRelease()
          Wait until the button is released.
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait
 

Field Detail

ENTER

public static final Button ENTER
The Enter button.


LEFT

public static final Button LEFT
The Left button.


RIGHT

public static final Button RIGHT
The Right button.


ESCAPE

public static final Button ESCAPE
The Escape button.


BUTTONS

public static final Button[] BUTTONS
Array containing ENTER, LEFT, RIGHT, ESCAPE, in that order.

Method Detail

getId

public final int getId()
Return the ID of the button. One of 1, 2, 4 or 8.


isPressed

public final boolean isPressed()
Check if the button is pressed.

Returns:
true if button is pressed, false otherwise.

waitForPressAndRelease

public final void waitForPressAndRelease()
                                  throws InterruptedException
Wait until the button is released.

Throws:
InterruptedException

addButtonListener

public void addButtonListener(ButtonListener aListener)
Adds a listener of button events. Each button can serve at most 4 listeners.


readButtons

public static int readButtons()
Low-level API that reads status of buttons.

Returns:
An integer with possibly some bits set: 0x01 (ENTER button pressed) 0x02 (LEFT button pressed), 0x04 (RIGHT button pressed), 0x08 (ESCAPE button pressed). If all buttons are released, this method returns 0.

callListeners

public void callListeners()
Call Button Listeners. Used by ListenerThread.

Specified by:
callListeners in interface ListenerCaller