Volume 7A: XView Programming Manual

D

Version 3.2 and the File Chooser

The XView File Chooser is an implementation of the OPENLOOK Application File Choosing

Specification. The Application File Choosing Specification supercedes the traditional

OPEN LOOK Style Guide on the subject of opening and saving files from an application,

without the use of the File Manager. The file chooser also lets the user easily navigate

through the file system. Note that the file chooser is not intended to replace the File Man-

ager; any application supporting the file chooser is also required by the File Choosing Speci-

fication to support drag and drop with the File Manager, in accordance with the OPEN LOOK

Drag and Drop Specification.

File choosers provide a simple and consistent interface for opening and saving files to the

UNIX File System. File choosers also provide a Go To Menu for going to different direc-

tories which allows the user to easily select a directory from a predefined list, an application

defined list or a dynamicly created history list. Normally a file chooser will be presented

from an application’s File Menu. The user will then have selections for opening a document,

saving a document, or saving a document to a new name. Once one of these selections is

made, a file chooser object is presented.

D.1 Creating File Choosers

To use the FILE_CHOOSER package, include the header file <xview/file_chsr.h>. The object

type is File_chooser. The class hierarchy for the FILE_CHOOSER package is:

[Generic] -> [(Drawable)] -> [Window] -> [Frame_cmd] -> [File Chooser]

File choosers come in three types:

• FILE_CHOOSER_OPEN

• FILE_CHOOSER_SAVE

• FILE_CHOOSER_SAVEAS

Figure D-1 shows an example of an OPEN file chooser.

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Figure D-1. File chooser Save dialog

678 Version 3.2 and the File Chooser

Figure D-2 shows an example of a SAVE file chooser which is similar to a SAVE AS file

chooser.

Figure D-2. File chooser Open dialog

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These dialogs are presented from an application’s file pop-up menu. The user may select one

of the predefined package choices: “Open”, "Save”, “Save As”, or an application defined

choice such as “Import” or “Include”. Once the file chooser is open, the user is presented

with a frame containing several elements for navigating the folder hierarchy. These elements

include the Go To menu, the Current Folder field, the scrolling list, and the Open, Save or

Save As button area, which also includes a Cancel button. The Save and Save As file chooser

also include a type in field below the scrolling list where the saved file is named. Refer to the

figures for the relative layouts of these file chooser elements. Note: the packages that make

up these elements are public and include: FILE_LIST, PATH_NAME, HISTORY_LIST and HIS-

TORY_MENU

. You can uses these packages for applications that require functionality similar

to that provided by any of these file chooser components. Refer to Section A.13, “File

Chooser Components” for information on using these packages. File chooser types are speci-

fied at create time using the FILE_CHOOSER_TYPE attribute. Alternatively, convenience

macros allow you to create each of the specified file chooser types as shown below:

File_chooser open_chsr;

File_chooser save_chsr;

File_chooser saveas_chsr;

open_chsr = (File_chooser) xv_create(owner,

FILE_CHOOSER_OPEN_DIALOG, NULL);

save_chsr = (File_chooser) xv_create(owner,

FILE_CHOOSER_SAVE_DIALOG, NULL);

saveas_chsr = (File_chooser) xv_create(owner,

FILE_CHOOSER_SAVEAS_DIALOG, NULL);

The owner of a File_chooser should be a base frame, but it can also be the root window,

NULL, just as with a command frame.

D.2 Using a File Chooser

Given the information provided so far, we can demonstrate to how to install a file chooser for

a menu item. Example D-1 shows a portion of a program which installs a File chooser on a

menu item. The complete program is found in Appendix F, Example Programs.

Example D-1. Portion of file_chooser.c program

/*

* Demonstrate the XView File Chooser

*/

#include <stdio.h>

#include <xview/xview.h>

#include <xview/panel.h>

#include <xview/textsw.h>

#include <xview/scrollbar.h>

#include <xview/file_chsr.h>

static Attr_attribute MY_KEY;

typedef struct {

Frame frame;

680 Version 3.2 and the File Chooser

Example D-1. Portion of file_chooser.c program (continued)

Panel panel;

Panel_button_item file_button;

Menu file_menu;

Textsw textsw;

File_chooser open;

File_chooser save;

File_chooser saveas;

File_chooser import;

char * doc_name;

} My_ui;

static void my_open_notify();

static void my_save_notify();

static void my_saveas_notify();

static void my_import_notify();

static int my_open_callback();

static int my_save_callback();

void

main( argc, argv )

int argc;

char **argv;

{

My_ui ui = {0};

(void) xv_init ( XV_INIT_ARGC_PTR_ARGV,

&argc, argv, NULL );

MY_KEY = xv_unique_key();

ui.file_menu

= xv_create(XV_NULL, MENU,

MENU_ITEM,

MENU_STRING, "Open...",

MENU_NOTIFY_PROC, my_open_notify,

NULL,

MENU_ITEM,

MENU_STRING, "Import...",

MENU_NOTIFY_PROC, my_import_notify,

NULL,

MENU_ITEM,

MENU_STRING, "Save...",

MENU_NOTIFY_PROC, my_save_notify,

NULL,

MENU_ITEM,

MENU_STRING, "Save As...",

MENU_NOTIFY_PROC, my_saveas_notify,

NULL,

XV_KEY_DATA, MY_KEY, &ui,

NULL);

ui.frame = xv_create(XV_NULL, FRAME,

XV_LABEL, "Demo Text Editor",

FRAME_SHOW_FOOTER, TRUE,

NULL );

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