A
JLabel
is the interface to the Java Swing JLabel Component.
Yoix programs normally interact with a
JLabel
using event handlers and by reading or writing the following fields:
| alignment |
An
int
that controls the horizontal positioning of the text in the label.
The value should be
LEFT,
CENTER,
RIGHT,
LEADING,
or
TRAILING,
which are all defined in
yoix.swing.
Reading returns the current alignment.
Writing immediately repaints the text using the new alignment.
| | altalignment |
An
int
that controls the vertical positioning of the text in the label.
The value should be
CENTER
(the default),
TOP,
or
BOTTOM,
which are all defined in
yoix.swing.
Reading returns the current altalignment.
Writing immediately repaints the text using the new altalignment.
| | autotrim |
An
int
that is
1
when white space is automatically trimmed from both ends of every string
read from or written to the
text
field, and
0
otherwise.
| | background |
The
Color
that is used to paint the background of the label.
Reading returns a snapshot of the current color.
Writing immediately changes the background to the new color.
Storing
NULL
in
background
is special and means use the background of the nearest component
that contains the label and was assigned a background color other than
NULL;
if no component qualifies the label uses
VM.screen.background.
| | border |
An
Object
that should be a
Border,
Insets,
Number,
or
String
that describes the border that is drawn around this label.
A
NULL
value, which is the default, means no border.
A
border
that is an
Insets
or
Number
is an easy way to describe margins
(i.e., an
EmptyBorder),
in units of 72 dots per inch, that are left around the sides of this label.
A
border
that is a
String
is a quick way to surround this label with a border that uses the
String
as its title.
Reading returns a snapshot of the current border.
Writing immediately sets the label's border to the new value.
| | cursor |
An
Object
that should be an
int,
Image,
or
String
that selects the cursor shown when the pointer is over the label.
A
cursor
that is an
int
should be one of the cursors defined in the
yoix.awt.Cursor
dictionary.
A
cursor
that is an
Image
can describe the cursor using its
size
and
hotspot
fields and often draws it using its
paint
function.
A
cursor
that is a
String
should be the name of a cursor that is already defined in
yoix.awt.Cursor
or the name a local a file or URL that contains a GIF or JPEG image
that will be used as the cursor.
Reading returns the current cursor.
Writing immediately changes the label's cursor to the new value.
Storing
STANDARD_CURSOR
(the default) or
NULL
in
cursor
is special and means use the cursor assigned to the nearest component
that contains the label and was assigned a cursor other than
STANDARD_CURSOR;
if no component qualifies the label uses
DEFAULT_CURSOR.
| | doublebuffered |
An
int
that is
1
when the label uses double-buffering to draw itself,
0
when it does not, and starts with a default value that is
selected by Java for the label.
Reading returns the current double-buffering behavior.
Writing immediately sets the label's double-buffering behavior to the new value.
Note that double-buffering may be required when transparent components are used.
| | dragenabled |
An
int
that should be set to
1
when this label wants to use the automatic drag handling that Swing provides
for some components, and
0
(the default)
when it does not.
Components that do not provide automatic drag handling always return
0
when their
dragenabled
field is read, so storing
1
in
dragenabled
should only be viewed as a request for a service that may not be available.
Swing components can always take complete control of their drag and drop
handling using their
transferhandler
field or special drag and drop event handlers.
| | enabled |
An
Object
that is
1
when the label can respond to user input,
0
when it can not respond, and
NULL
(the default)
when the label inherits the value from the nearest lightweight container,
like a
JPanel,
that contains the label and has its
enabled
field set to something other than
NULL.
The top-level application window that contains the label always gets the
final say, so disabling that window always disables the label.
Reading returns the current state.
Writing immediately sets the label's state to the new value.
| | focusable |
An
int
that is non-zero (the default)
when the label can accept the keyboard focus and zero
when it can not.
Reading returns the label's current focusable state.
Writing immediately changes the label's focusable state to the new value,
which means the focus is automatically transferred if the new value is zero
and the label is the current focus owner.
| | focusowner |
A read-only
int
that is non-zero when the label has the focus.
| | font |
The
Font,
or font name if it is a
String,
used to paint the characters stored in the
text
field.
Reading returns a snapshot of the current font.
Writing immediately repaints the text in the new font.
| | foreground |
The
Color
that is used to paint the characters stored in the
text
field.
Reading returns a snapshot of the current color.
Writing immediately repaints the label in the new color.
Storing
NULL
in
foreground
is special and means use the foreground of the nearest component
that contains the label and was assigned a foreground color other than
NULL;
if no component qualifies the label uses
VM.screen.foreground.
| | icon |
A read-write
Image
displayed as an icon along with the text, if any, in this label.
| | layer |
An
int,
often a small number between 0 and 99,
that identifies the depth of this label when it is added to a
JLayeredPane
or
JDesktopPane.
Components assigned to lower numbered layers are drawn before
the components in higher numbered layers.
Writing immediately changes the label's layer, which usually means the
JLayeredPane
or
JDesktopPane
that contains the label will be repainted.
| | location |
A
Point
that determines the location of the label
in a coordinate system that has its origin at the upper left corner
of the container closest to the label (in the component hierarchy)
that actually contains it, positive x to the right, positive y down,
and a resolution of 72 dots per inch.
Reading returns a snapshot of the current location.
Writing is allowed, but layout managers usually get the final say, so setting
location
should be viewed as a request that may not be honored.
| | nextfocus |
An
Object
that identifies the component that receives the focus after this label
when the focus traverses from one component to the next
(usually by means of the keyboard
TAB
character).
When
nextfocus
is a
String
it is assumed to be the tag associated with the target component,
which must belong to the same top-level container (e.g., the same
JFrame)
as this label.
A
NULL
value means the component that gets the focus after this label will be
selected by Java's default focus traversal policy.
Reading returns the value last stored or
NULL
if the value was a
String
that did not reference a component.
Writing immediately changes the component that gets the focus after this label.
| | opaque |
An
Object
that is
1
when the label is opaque,
0
when it is transparent, and
NULL
(the default)
when the label inherits the value from the nearest component that
contains the label and has its
opaque
field set to something other than
NULL.
| | popup |
A
JPopupMenu
that is associated with the label.
Reading returns the current popup menu.
Writing immediately shows the popup menu at the point in the label's coordinate
system specified by the popup menu's
location
field, assuming of course that the label is showing on the screen.
Storing
TRUE
in the popup menu's
visible
field, which was added in release 1.2.0, is an easy way to show the
popup menu that currently belongs to the label.
| | preferredsize |
A
Dimension
that is used by layout managers when they need to know the label's
preferred size in units of 72 dots per inch.
A
NULL
value means the label has no preference.
A non-positive height or width is allowed and simply means the label
has no preference for that dimension.
Reading returns the current preferred size.
Writing changes the preferred size and immediately notifies
root.layoutmanager,
which means the components contained in
root
may be repositioned and resized.
| | requestfocus |
An
int
that can be used to request or transfer the keyboard focus.
Storing a non-zero value in
requestfocus
tries to get the focus.
Storing
0
tries to transfer the focus.
Reading
requestfocus
does not currently return any useful information.
| | requestfocusenabled |
An
int
that is
1
(the default)
when actions, like mouse clicks or changes to the
requestfocus
field, can steal the keyboard focus and
0
when they can not.
Note that this field does not affect acceptance of the keyboard focus
during normal focus traversal.
Reading returns the current state.
Writing immediately sets the label's state to the new value.
| | root |
An
Object
that is automatically updated by the interpreter's layout machinery
so it is always the top-level object that contains the label.
For example, put a label in a panel and
root
will be set to that panel;
add the panel to a frame and the label's
root
field will be set to that frame.
A label's event handlers can use
root
when they need to interact with the other components in the container.
| | showing |
A read-only
int
that is non-zero when the label is showing on the screen.
| | size |
A
Dimension
that determines the size of the label
in units of 72 dots per inch.
Reading returns a snapshot of the current size.
Writing is allowed, but layout managers usually get the final say, so setting
size
should be viewed as a request that may not be honored.
| | tag |
A
String
used to identify the label that is either supplied when
the label is declared, or automatically generated otherwise.
Add a label to a container, like a
Frame
or
Panel,
and the interpreter's layout machinery updates the
root
field so it points at the top-level container and then adds the label, as
tag,
to the
root.components
dictionary.
| | text |
A
String
of characters that is displayed in the label.
Reading returns the current text.
Writing immediately paints the new text.
| | textposition |
An
int
that controls the horizontal positioning of the text in the label relative to its icon.
The value should be
LEFT,
CENTER,
RIGHT,
LEADING,
or
TRAILING,
which are all defined in
yoix.swing.
Reading returns the current alignment.
Writing immediately repaints the text using the new alignment.
The default value is
TRAILING.
| | tooltiptext |
A
String
of characters that is displayed in a tightly sized pop-up window that
appears near the cursor whenever the cursor lingers over the label.
Setting this value to
NULL
(the default)
disables the tooltip mechanism.
Reading returns the current tooltip text.
Writing immediately sets the new tooltip text.
| | transferhandler |
An
Object
that should be a
TransferHandler
or
String
that determines how the label handles data transfer operations
like drag and drop.
A value that is a
String
but not
""
means the field named by the
String
should be used as the source and sink of the data that is transferred by
the label.
The result is the same as assigning the
String
to the
property
field in a
TransferHandler
and then assigning that
TransferHandler
to
transferhandler.
The empty
String
""
is special and refers to the
TransferHandler
that Swing uses for automatic drag handling, if there is one.
Swing components that provide automatic drag handling start out with a
transferhandler
field that is not
NULL,
but the automatic drag handling is not enabled until
1
is stored in
dragenabled.
Swing components that provide their own drag and drop event handlers
currently must store
NULL
in
transferhandler
before those event handlers will start working.
| | visible |
An
int
that is
1
when the label is visible, and
0
otherwise.
Reading returns the current visibility.
Writing immediately sets the label's visibility to the new state.
|
Several permanent fields have not been documented and should not be
used in Yoix applications.
Event handlers are functions that must be added to a label when it is
declared.
The handlers that work with labels are listed below;
the names should be familiar if you have done some Java programming.
The
actionPerformed
and
itemStateChanged
event handlers are only for menus.
| |
| Event Handlers: |
actionPerformed,
componentHidden,
componentMoved,
componentResized,
componentShown,
dragDropEnd,
dragEnter,
dragExit,
dragGestureRecognized,
dragMouseMoved,
dragOver,
drop,
dropActionChanged,
focusGained,
focusLost,
invocationRun,
itemStateChanged,
keyPressed,
keyReleased,
keyTyped,
mouseClicked,
mouseDragged,
mouseEntered,
mouseExited,
mouseMoved,
mousePressed,
mouseReleased,
mouseWheelMoved
| | |
| Example: |
The program,
import yoix.*.*;
JFrame f = {
Array layout = {
new JLabel {
String text = "Here's some text";
String tag = "label";
Color foreground = Color.red;
int alignment = LEFT;
},
};
};
f.visible = TRUE;
sleep(3);
f.components.label.alignment = RIGHT;
sleep(3);
f.components.label.alignment = CENTER;
sleep(3);
f.components.label.text = "";
f.components.label.font = "Helvetica-bold-14";
f.components.label.text = "ALL DONE...";
sleep(3);
exit(0);
adds a label to to a frame, lets you watch as some of the fields
are changed, and then quits.
| | |
| See Also: |
appendText,
BevelBorder,
Border,
EmptyBorder,
EtchedBorder,
invokeLater,
JButton,
JCanvas,
JCheckBox,
JCheckBoxMenuItem,
JChoice,
JColorChooser,
JComboBox,
JDesktopPane,
JDialog,
JFileChooser,
JFileDialog,
JFrame,
JInternalFrame,
JLayeredPane,
JList,
JMenu,
JMenuBar,
JMenuItem,
JPanel,
JPasswordField,
JPopupMenu,
JProgressBar,
JRadioButton,
JRadioButtonMenuItem,
JScrollBar,
JScrollPane,
JSeparator,
JSlider,
JSplitPane,
JTabbedPane,
JTable,
JTextArea,
JTextCanvas,
JTextField,
JTextPane,
JTextTerm,
JToggleButton,
JToolBar,
JTree,
JWindow,
LineBorder,
MatteBorder,
postEvent,
SoftBevelBorder,
TransferHandler
|
|
