A
MenuBar
is the interface to Java's AWT MenuBar MenuComponent.
Yoix programs normally interact with them by adding event handlers
to the frame that owns the menubar, and by reading or writing the following
MenuBar
fields:
| font |
The
Font,
or font name if it is a
String,
used to draw the text strings in the menubar and its submenus.
Unfortunately Windows seems to ignore all font requests,
and on other platforms menubars may have to be removed and reattached
before font changes take effect.
| | 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 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
array, organized in pairs, that completely describes the menubar.
The first element in each pair must be a string that is used as a label
on the menubar.
The second element in each pair must be another
Menu
array that describes the submenu that is placed under its
label on the menubar.
| | 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 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.
| | visible |
An
int
that is
1
when the menubar is visible, and
0
otherwise.
Writing immediately sets the menubar's visibility to the new state.
Unfortunately, reading this field does not always return an accurate
representation of the menubar's state.
|
Several permanent fields have not been documented and should not be
used in Yoix applications.
A menubar can be attached to a frame by assigning it to the frame's
menubar
field.
Only one frame can own a menubar, so attaching it to a frame
automatically removes the menubar from the current owner,
if there is one.
Storing
NULL
in a frame's
menubar
field removes the current menubar.
Selecting a regular menu item delivers an
ActionEvent
to the
actionPerformed
event handler defined in the frame that currently owns the menubar.
Selecting a checkbox menu item delivers an
ItemEvent
to the
itemStateChanged
event handler defined in that same frame.
| |
| Example: |
The program,
import yoix.*.*;
MenuBar menubar = {
Menu items = {
"File", new Menu {
"Open", new Dictionary {
String command = "open";
String accelerator = "ctrl O";
int enabled = FALSE;
},
"Close", new Dictionary {
String command = "close";
String accelerator = "ESCAPE";
},
"-", NULL,
"Exit", "exit",
},
"Edit", new Menu {
"Save", "save1", 1,
"Save As", "save2",
},
};
};
Frame f = {
MenuBar menubar = menubar;
GridLayout layoutmanager = {
int rows = 1;
};
Array layout = {
new Button {
String text = "Toggle MenuBar";
actionPerformed(e) {
if (root.menubar == NULL)
root.menubar = global.menubar;
else root.menubar = NULL;
}
},
new Button {
String text = "Show MenuBar";
actionPerformed(e) {
root.menubar = global.menubar;
}
},
new Button {
String text = "Hide MenuBar";
actionPerformed(e) {
root.menubar = NULL;
}
},
};
actionPerformed(e) {
printf("Received: %O\n", e);
if (strcmp(e.command, "exit") == 0)
exit(0);
}
itemStateChanged(e) {
printf("Received: %O\n", e);
}
};
f.visible = TRUE;
adds and removes a menubar from a frame and shows how menu selections
get back to the frame's
actionPerformed
and
itemStateChanged
event handlers.
| | |
| See Also: |
Frame,
Menu,
PopupMenu
|
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