A
JPopupMenu
is the interface to the Java Swing JPopupMenu MenuComponent.
Yoix programs normally interact with them by adding event handlers
to the component that owns the popupmenu, and by reading or writing
the following
JPopupMenu
fields:
| 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 popupmenu.
It is also the default background color assigned to components in the
items
array that do not pick their own.
The default value is
NULL,
which means use the background color of the component owns the popupmenu.
Reading returns a snapshot of the current color.
Writing immediately sets the popupmenu's background,
and the background of components contained in the popupmenu
that do not pick their own, to the new color.
| | border |
An
Object
that should be a
Border,
Insets,
Number,
or
String
that describes the border that is drawn around this popupmenu.
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 popupmenu.
A
border
that is a
String
is a quick way to surround this popupmenu with a border that uses the
String
as its title.
Reading returns a snapshot of the current border.
Writing immediately sets the popupmenu's border to the new value.
| | components |
A
Dictionary
maintained by the interpreter that maps
tag
fields to actual menu components;
every menu component contained in the popupmenu has an entry in the dictionary.
| | cursor |
An
Object
that should be an
int,
Image,
or
String
that selects the cursor shown when the pointer is over the popupmenu.
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 sets the popupmenu's cursor to the new value.
A popupmenu that does not set its own cursor uses
DEFAULT_CURSOR.
| | doublebuffered |
An
int
that is
1
when the popupmenu uses double-buffering to draw itself,
0
when it does not, and starts with a default value that is
selected by Java for the popupmenu.
Reading returns the current double-buffering behavior.
Writing immediately sets the popupmenu'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 popupmenu 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
int
that is
1
when the popupmenu can respond to user input, and
0
when it can not.
The top-level application window that contains the popupmenu always gets the
final say, so disabling that window always disables the popupmenu.
Reading returns the current state.
Writing immediately sets the popupmenu's state to the new value.
| | font |
The
Font,
or font name if it is a
String,
that is used as the default font assigned to popupmenu and the components in the
items
array that do not pick their own.
The default value is
NULL,
which means use the font selected by the component that owns the popupmenu.
Reading returns a snapshot of the current font.
Writing immediately changes the popupmenu's font,
and the font used by all components contained in the popupmenu
that do not pick their own, to the new font.
| | foreground |
The
Color
that is used as the default foreground color assigned to
the popupmenu and components in the
items
array that do not pick their own.
The default value is
NULL,
which means use the foreground color of the component that owns the popupmenu.
Reading returns a snapshot of the current color.
Writing immediately sets the popupmenu's foreground,
and the foreground of components contained in the popupmenu
that do not pick their own, to the new color.
| | getEnabled(Object pattern) |
A
Builtin
that finds the first menu item with a command that matches
pattern,
which can be a
String
or
Regexp,
and returns
1
if it is currently enabled (i.e., it will respond when selected by a user),
0
if not, and
-1
if there is no match.
| | getState(Object pattern) |
A
Builtin
that finds the first checkbox or radiobutton menu item with a command that matches
pattern,
which can be a
String
or
Regexp,
and returns
1
if it is currently selected,
0
if not, and
-1
if there is no match.
| | items |
A
Menu
that describes the popupmenu configuration or an
Array
of the
JMenu
or
JMenuItem
objects that are actually in the popupmenu.
Writing causes the new
Array
or
Menu
to be parsed and if there are no errors immediately resets the menu's contents.
| | location |
A
Point
that determines where popupmenu is shown.
Coordinates describe a location in the component that currently owns
the popupmenu in a coordinate system that has its origin at that component's
upper left corner, positive x to the right, positive y down,
and a resolution of 72 dots per inch.
In practice
location
is often set using the
location
that is available in a
MouseEvent.
| | preferredsize |
A
Dimension
that is used by layout managers when they need to know the popupmenu's
preferred size in units of 72 dots per inch.
A
NULL
value means the popupmenu has no preference.
A non-positive height or width is allowed and simply means the popupmenu
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.
| | root |
An
Object
that is automatically updated by the interpreter so it always references
the component that currently owns the popupmenu.
A
NULL
value means the popupmenu is not currently attached to a component.
| | setEnabled(Object pattern, int state) |
A
Builtin
that finds menu items with commands that match
pattern,
which can be a
String
or
Regexp,
and enables them (i.e., they respond when selected by a user) when
state
is non-zero and disables them when
state
is zero.
A return value of
-1
means there were no matches.
| | setState(Object pattern, int state) |
A
Builtin
that finds checkbox or radiobutton menu items with commands that match
pattern,
which can be a
String
or
Regexp,
and selects them when
state
is non-zero and deselects them when
state
is zero.
A return value of
-1
means there were no matches.
| | showing |
A read-only
int
that is non-zero when the popupmenu is showing on the screen.
| | size |
A
Dimension
that determines the size of the popupmenu
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.
| | text |
A
String
of characters that labels the popupmenu.
Reading returns the current text.
Writing immediately paints the new text.
| | 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 popupmenu.
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 popupmenu 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 popupmenu.
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 popupmenu is visible, and
0
otherwise.
Reading returns the current visibility.
Writing immediately sets the popupmenu's visibility to the new state.
Setting this field to
0
effectively pops down the popupmenu.
|
Several permanent fields have not been documented and should not be
used in Yoix applications.
In addition, even though the
layer,
opaque,
nextfocus,
requestfocus,
and
requestfocusenabled
fields are defined, in most situations they have no effect and as a result
they have not been documented.
A popupmenu can be shown over any component, except other menus and menu
items, by assigning it to that component's
popup
field.
Only one component can show a popupmenu, so assigning it to a different
component automatically hides the popupmenu if it was being shown over
a different component.
Selecting a regular menu item delivers an
ActionEvent
to the
actionPerformed
event handler defined in the component that currently owns the popupmenu or
the
actionPerformed
event handler in the menu item itself.
Selecting a checkbox menu item delivers an
ItemEvent
to the
itemStateChanged
event handler defined either in the popupmenu owner or the menu item
itself.
Popup menus are usually shown in response to a
MouseEvent
that has its
popuptrigger
field set to
1.
Unfortunately, the mouse event that serves as a popup trigger
is platform dependent
(e.g., press a button on UNIX and release a button on Windows),
so applications that use popupmenus should check
popuptrigger
in
mousePressed
and
mouseReleased
event handlers.
| |
| Event Handlers: |
actionPerformed,
invocationRun,
itemStateChanged
| | |
| Example: |
The program,
import yoix.*.*;
JPopupMenu popupmenu = {
String text = "Test Popup Menu";
Menu items = {
"Line 1", "1",
"Line 2", "2",
"More...", new Menu {
"Line 3", "3",
"Line 4", "4", TRUE,
},
"-", NULL,
"Exit", "exit",
};
};
mouseEventHandler(e) {
if (e.popuptrigger) {
global.popupmenu.location = e.location;
this.popup = global.popupmenu;
}
}
JFrame f = {
GridLayout layoutmanager;
Array layout = {
new JLabel {
String text = "Label 1";
Color background = Color.red;
int alignment = CENTER;
Function mousePressed = mouseEventHandler;
Function mouseReleased = mouseEventHandler;
actionPerformed(e) {
printf("Received: %O\n", e);
if (strcmp(e.command, "exit") == 0)
exit(0);
}
},
new JLabel {
String text = "Label 2";
Color background = Color.green;
int alignment = CENTER;
Function mousePressed = mouseEventHandler;
Function mouseReleased = mouseEventHandler;
itemStateChanged(e) {
printf("Received: %O\n", e);
}
},
};
};
f.visible = TRUE;
shows how different components can show the same popupmenu,
and how menu selections get back to the
actionPerformed
and
itemStateChanged
event handlers defined in the component that is showing the popupmenu.
| | |
| See Also: |
appendText,
BevelBorder,
Border,
EmptyBorder,
EtchedBorder,
invokeLater,
JButton,
JCanvas,
JCheckBox,
JCheckBoxMenuItem,
JChoice,
JColorChooser,
JComboBox,
JDesktopPane,
JDialog,
JFileChooser,
JFileDialog,
JFrame,
JInternalFrame,
JLabel,
JLayeredPane,
JList,
JMenu,
JMenuBar,
JMenuItem,
JPanel,
JPasswordField,
JProgressBar,
JRadioButton,
JRadioButtonMenuItem,
JScrollBar,
JScrollPane,
JSeparator,
JSlider,
JSplitPane,
JTabbedPane,
JTable,
JTextArea,
JTextCanvas,
JTextField,
JTextPane,
JTextTerm,
JToggleButton,
JToolBar,
JTree,
JWindow,
LineBorder,
MatteBorder,
Menu,
postEvent,
SoftBevelBorder,
TransferHandler
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