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java.lang.Object
|
+--net.rim.device.api.ui.Field
|
+--net.rim.device.api.ui.component.ButtonField
Contains a button control.
When the user presses a ButtonField the FieldChangeListener that
was set by invoking setChangeListener() is notified by its
fieldChanged() method being invoked.
The code below demonstrates how to use this technique to respond to button presses.
FieldChangeListener listener = new FieldChangeListener() {
public void fieldChanged(Field field, int context) {
ButtonField buttonField = (ButtonField) field;
System.out.println("Button pressed: " + buttonField.getLabel());
}
};
ButtonField buttonField = new ButtonField("Test Button");
buttonField.setChangeListener(listener);
After buttonField is added to a screen, the text
"Button pressed: Test Button" will be printed to System.out each time
the button is pressed.
The default alignment of a button will be DrawStyle.VCENTER
and DrawStyle.HCENTER. The label will be centered vertically
and horizontally.
Behaviour
Displays a button.
| Field Summary | ||
static int |
BARE
Deprecated. Used only for non-color devices. |
|
static long |
CONSUME_CLICK
Indicates to the button consume the click event. |
|
static long |
NEVER_DIRTY
Indicates to the button not become dirty or muddy on the click event. |
|
| Fields inherited from interface net.rim.device.api.ui.DrawStyle |
BASELINE, BOTTOM, ELLIPSIS, HALIGN_MASK, HCENTER, HDEFAULT, HFULL, LEADING, LEFT, RIGHT, TOP, TRAILING, TRUNCATE_BEGINNING, VALIGN_MASK, VCENTER, VDEFAULT, VFULL |
| Constructor Summary | ||
ButtonField()
Constructs a new ButtonField instance. |
||
ButtonField(long style)
Constructs a new ButtonField instance with provided style. |
||
ButtonField(String label)
Constructs a new ButtonField instance with provided label. |
||
ButtonField(String label,
long style)
Constructs a new ButtonField instance with provided label and style. |
||
| Method Summary | ||
protected void |
drawFocus(Graphics graphics,
boolean on)
Draws the focus indicator for this field. |
|
AccessibleContext |
getAccessibleContext()
Returns accessible representation of the field for a screen reader |
|
String |
getLabel()
Retrieves this field's label. |
|
int |
getPreferredHeight()
Retrieves this field's preferred height. |
|
int |
getPreferredWidth()
Retrieves this field's preferred width. |
|
|
protected boolean |
invokeAction(int action)
Invokes an action on this field. |
protected boolean |
keyChar(char key,
int status,
int time)
Traps ENTER key generation events. |
|
protected boolean |
keyDown(int keycode,
int time)
Handles key down events. |
|
protected boolean |
keyUp(int keycode,
int time)
Handles key up events. |
|
protected void |
layout(int width,
int height)
Lays out this field's contents. |
|
|
protected void |
onUnfocus()
Invoked when a field loses the focus. |
protected void |
paint(Graphics graphics)
Redraws this field. |
|
void |
setDirty(boolean dirty)
Sets the dirty state of the field. |
|
void |
setLabel(String label)
Sets label string for this field. |
|
void |
setMuddy(boolean muddy)
Sets the muddy state for this field. |
|
protected boolean |
trackwheelClick(int status,
int time)
Handles trackwheel click events. |
|
protected boolean |
trackwheelUnclick(int status,
int time)
Indicates a trackwheel release event. |
|
| Methods inherited from class java.lang.Object |
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Field Detail |
public static final long CONSUME_CLICK
public static final long NEVER_DIRTY
| Constructor Detail |
public ButtonField(long style)
style - Field style for the button: can be a combation of any
generic field style, BARE, DrawStyle.ELLIPSIS,
Field.FOCUSABLE, Field.NON_FOCUSABLE,
any of Field's horizontal or vertical alignment styles. The
default horizontal alignment will be DrawStyle.HCENTER, and
the default vertical alignment will be DrawStyle.VCENTER.public ButtonField(String label)
Provided a label string to show, this method builds a button field in the default style.
label - Label string for the button.public ButtonField(String label, long style)
Provided a label string to show, and a style, this method builds a button field using your style.
label - Label string for the button.style - Field style for the button: can be a combation of any
generic field style, BARE, DrawStyle.ELLIPSIS,
Field.FOCUSABLE, Field.NON_FOCUSABLE and
any of Field's horizontal or vertical alignment styles. The
default horizontal alignment will be DrawStyle.HCENTER, and
the default vertical alignment will be DrawStyle.VCENTER.| Method Detail |
protected void drawFocus(Graphics graphics, boolean on)
This field's manager invokes this method after applyThemeOnStateChangeing this field. The manager initializes the graphics object passed in for drawing with field-local coordinates.
This method inverts the focus rect obtained from
Field.getFocusRect(net.rim.device.api.ui.XYRect).
graphics - Graphics context used for drawing the focus.on - True if the focus should be set; otherwise, false.public AccessibleContext getAccessibleContext()
getAccessibleContext in class Fieldpublic String getLabel()
public int getPreferredHeight()
Field.getPreferredHeight() for more information.
This field's manager invokes this method to assist in its layout.
getPreferredHeight in class Fieldpublic int getPreferredWidth()
Field.getPreferredWidth() for more information.
This field's manager invokes this method to assist in its layout.
getPreferredWidth in class Fieldprotected boolean invokeAction(int action)
Field.ACTION_INVOKE, which simulates this button being pressed.
If action is not a recognized action then this method does nothing and
returns false, indicating that the action was not consumed.
invokeAction in class Fieldaction - the action to be performed on this field.true if the action was consumed; false
if the action was not consumed.
protected boolean keyChar(char key,
int status,
int time)
This method handles and consumes a key generation event, if it's the ENTER key that's generated; otherwise, this method does nothing and does not consume the event.
key - Character generated by the event.status - Modifier key status (this parameter is ignored).time - Number of milliseconds since the device was turned on.
protected boolean keyDown(int keycode,
int time)
By default, this method returns false; custom fields that specially handle key down events must override this method.
keycode - Code of key pressed.time - Number of milliseconds since the device was turned on.
protected boolean keyUp(int keycode,
int time)
By default, this method returns false; custom fields that specially handle key up events must override this method.
keycode - Code of key released.time - Number of milliseconds since the device was turned on.
protected void layout(int width,
int height)
This field's manager invokes this method during the layout process to instruct this field to arrange its contents, given an amount of available space.
width - Amount of available horizontal space.height - Amount of available vertical space.protected void onUnfocus()
The method will not be invoked if this field does not already have the focus.
public void setDirty(boolean dirty)
Invoke this method to indicate either that a field's contents have changed (passing true), or that a field's changes have been dealt with and is no longer dirty (passing false).
dirty - Specify true if this field is dirty; otherwise, specify
false to set the field to clean.public void setLabel(String label)
label - Label string for this field.
protected boolean trackwheelClick(int status,
int time)
The system invokes this method when passing on a trackwheel click event. This method is transparent, and the event is not consumed.
trackwheelClick in class Fieldstatus - State of the modifier keys.time - Number of milliseconds since the device was turned on.
protected boolean trackwheelUnclick(int status,
int time)
The system invokes this method when passing on a trackwheel release event.
trackwheelUnclick in class Fieldstatus - Bitfield of values defined by Keypad.time - Number of milliseconds since the device was turned on.
|
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