lejos.nxt
Class Button

java.lang.Object
  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 int	ID_ENTER
static int	ID_ESCAPE
static int	ID_LEFT
static int	ID_RIGHT
static Button	LEFT The Left button.
static Button	RIGHT The Right button.
static String	VOL_SETTING

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.
static int	getKeyClickLength() Return the current key click length.
static int	getKeyClickTone(int key) Return the click freq for a particular key.
static int	getKeyClickVolume() Return the current key click volume.
boolean	isPressed() Check if the button is pressed.
static void	loadSettings() Load the current system settings associated with this class.
static int	readButtons() Low-level API that reads status of buttons.
static void	setKeyClickLength(int len) Set the len used for key clicks
static void	setKeyClickTone(int key, int freq) Set the frequency used for a particular key.
static void	setKeyClickVolume(int vol) Set the volume used for key clicks
static int	waitForPress() wait for some button to be pressed (and released).
void	waitForPressAndRelease() Wait until the button is released.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ID_ENTER

public static final int ID_ENTER

See Also:

Constant Field Values

ID_LEFT

public static final int ID_LEFT

See Also:

Constant Field Values

ID_RIGHT

public static final int ID_RIGHT

See Also:

Constant Field Values

ID_ESCAPE

public static final int ID_ESCAPE

See Also:

Constant Field Values

VOL_SETTING

public static final String VOL_SETTING

See Also:

Constant Field Values

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

waitForPress

public static int waitForPress()

wait for some button to be pressed (and released).

Returns:

the ID of that button, the same as readButtons();

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

setKeyClickVolume

public static void setKeyClickVolume(int vol)

Set the volume used for key clicks

Parameters:

vol -

getKeyClickVolume

public static int getKeyClickVolume()

Return the current key click volume.

Returns:

current click volume

setKeyClickLength

public static void setKeyClickLength(int len)

Set the len used for key clicks

Parameters:

len - the click duration

getKeyClickLength

public static int getKeyClickLength()

Return the current key click length.

Returns:

key click duration

setKeyClickTone

public static void setKeyClickTone(int key,
                                   int freq)

Set the frequency used for a particular key. Setting this to 0 disables the click. Note that key may also be a corded set of keys.

Parameters:

key - the NXT key

freq - the frequency

getKeyClickTone

public static int getKeyClickTone(int key)

Return the click freq for a particular key.

Returns:

key click duration

loadSettings

public static void loadSettings()

Load the current system settings associated with this class. Called automatically to initialize the class. May be called if it is required to reload any settings.