A
FileDialog
represents a top-level application window that is implemented using Java's
AWT FileDialog class.
A filedialog consumes system resources that are currently only returned after
the filedialog is explicitly disposed, which happens when your program stores
a non-zero value in the filedialog's
dispose
field.
Filedialogs are a platform dependent tool that lets users browse
though a file system and select at most one file that is supposed to
be read or written.
Yoix programs normally interact with a
FileDialog
using event handlers and by reading or writing the following fields:
| autodispose |
An
int
that arranges to dispose the filedialog,
exactly as if a non-zero value had been stored in the
dispose
field, whenever a visible filedialog is hidden while
autodispose
is non-zero.
Failure to dispose of unused filedialogs means system resources are lost,
and that can eventually affect the performance of your program.
| | background |
The
Color
that is used to paint the background of the filedialog.
Reading returns a snapshot of the current color.
Writing is not allowed and will result in an
invalidaccess
error.
| | directory |
A
String
that names the directory where the filedialog looks for files.
When the filedialog is made visible it always starts looking for files
in the directory that was last stored in the
directory
field.
Reading returns the directory where the last file was found,
or the current starting directory if no file was selected.
Writing changes the starting directory that is used the next time the
filedialog is made visible.
| | dispose |
An
int
that is
1
when the filedialog has been properly disposed and
0
otherwise.
Reading returns the current dispose state.
Writing a non-zero value
immediately disposes the filedialog;
writing
0
has no effect, which means you cannot
resurrect a disposed filedialog.
Failure to dispose of unused filedialogs means system resources are lost,
and that can eventually affect the performance of your program.
| | enabled |
An
int
that is
1
when the filedialog can respond to user input, and
0
when it can not.
Reading returns the current state.
Writing immediately sets the filedialog's state to the new value.
| | file |
A
String
that names the file selected by the filedialog.
When the filedialog is made visible the starting value is the last name
that was stored in the
file
field.
Reading returns the last selected file, or
NULL
if no file was selected,
usually because the Cancel button was pushed.
Writing changes the starting file that is used the next time the
filedialog is made visible.
| | font |
The
Font
that is used by the filedialog.
Reading returns a snapshot of the current font.
Writing is not allowed and will result in an
invalidaccess
error.
| | foreground |
The
Color
that is used to paint the foreground of the filedialog.
Reading returns a snapshot of the current color.
Writing is not allowed and will result in an
invalidaccess
error.
| | layoutmanager |
A
LayoutManager
that is permanently set to
NULL,
because filedialogs take complete responsibility for their own layout.
Writing is not allowed and will result in an
invalidaccess
error.
| | location |
A
Point
that is permanently set to
NULL,
because Java's FileDialog class does not seem to respond to requests
that should move the filedialog.
Writing is not allowed and will result in an
invalidaccess
error.
| | mode |
An
int
that should be
OPEN
(the default) or
LOAD
when the selected file will be read and
SAVE
when it will be written.
All three constants are defined in
yoix.awt.
Reading returns the current mode.
Writing changes the filedialog's mode, which may also change its
appearance the next time it is made visible.
| | parent |
A window, which usually should be a
Frame,
Dialog,
FileDialog,
or
Window,
Hiding, disposing, iconifying or deiconifying the parent does the same
thing to its children, so using a parent is a convenient way to manage
a group of windows.
Reading returns the current parent.
Writing immediately sets the filedialog's parent to the new value.
| | root |
A read-only field that for convenience always points to the filedialog itself.
A filedialog is top-level container with a fixed
layoutmanager
that that is completely responsible fot its own layout, so the
root
field is not particularly useful.
| | showing |
A read-only
int
that is non-zero when the filedialog is showing on the screen.
Reading
showing
or
visible
produce identical results for a top-level container like a filedialog.
| | size |
A
Dimension
that is permanently set to
NULL,
because Java's FileDialog class does not seem to respond to requests
that should resize the filedialog.
Writing is not allowed and will result in an
invalidaccess
error.
| | tag |
A
String
used to identify the filedialog that is either supplied when
the filedialog is declared, or automatically generated otherwise.
Filedialogs are top-level containers, so the
tag
field is not particularly useful and may be deleted in future releases.
| | toyoixpath |
An
int
that controls what happens to platform dependent file separators when the
file
and
directory
fields are read.
When
toyoixpath
is non-zero all file separators are replaced by the slash character
/,
otherwise no changes are made.
| | visible |
An
int
that is
1
when the filedialog is visible, and
0
otherwise.
Reading returns the current visibility.
Writing immediately sets the filedialog'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 filedialog when it is
declared.
The handlers that work with filedialogs are listed below;
the names should be familiar if you have done some Java programming.
We have not listed any
DragGestureEvent,
DragSourceEvent,
DropTargetEvent,
FocusEvent,
KeyEvent,
or
MouseEvent
handlers because the experiments that we ran were either unsuccessful
or inconsistent.
A filedialog completely blocks the rest of your application while it is
visible.
After its dismissed, the full pathname of the selected file is obtained
by concatenating the
directory
and
file
fields;
the style of that pathname is controlled by the
toyoixpath
field.
| |
| Event Handlers: |
componentHidden,
componentMoved,
componentResized,
componentShown,
invocationRun,
windowActivated,
windowClosed,
windowClosing,
windowDeactivated,
windowDeiconified,
windowIconified,
windowOpened
| | |
| Example: |
The program,
import yoix.*.*;
FileDialog fd = {
String directory = VM.tmpdir;
int mode = SAVE;
};
fd.visible = TRUE;
if (fd.file != NULL)
printf("You selected: %s%s\n", fd.directory, fd.file);
else printf("You made no selection\n");
shows a filedialog that starts in your system's temp directory.
Pick a file and the full pathname should print on standard output;
hit the Cancel button and you should see
You made no selection
on standard output.
| | |
| See Also: |
Button,
Canvas,
Checkbox,
Choice,
Dialog,
Frame,
Label,
List,
Panel,
postEvent,
ScrollPane,
Scrollbar,
TableColumn,
TableManager,
TextArea,
TextCanvas,
TextField,
TextTerm,
Window,
yoixPath
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