Fl_Native_File_Chooser Class Reference

This class lets an FLTK application easily and consistently access the operating system's native file chooser. More...

#include <Fl_Native_File_Chooser.H>

Public Types
enum	Option {   NO_OPTIONS = 0x0000 , SAVEAS_CONFIRM = 0x0001 , NEW_FOLDER = 0x0002 , PREVIEW = 0x0004 ,   USE_FILTER_EXT = 0x0008 }
enum	Type {   BROWSE_FILE = 0 , BROWSE_DIRECTORY , BROWSE_MULTI_FILE , BROWSE_MULTI_DIRECTORY ,   BROWSE_SAVE_FILE , BROWSE_SAVE_DIRECTORY }

Public Member Functions
int	count () const
	Returns the number of filenames (or directory names) the user selected. More...
const char *	directory () const
	Returns the current preset directory() value.
void	directory (const char *val)
	Preset the directory the browser will show when opened. More...
const char *	errmsg () const
	Returns a system dependent error message for the last method that failed. More...
const char *	filename () const
	Return the filename the user chose. More...
const char *	filename (int i) const
	Return one of the filenames the user selected. More...
const char *	filter () const
	Returns the filter string last set. More...
void	filter (const char *f)
	Sets the filename filters used for browsing. More...
int	filter_value () const
	Returns which filter value was last selected by the user. More...
void	filter_value (int i)
	Sets which filter will be initially selected. More...
int	filters () const
	Gets how many filters were available, not including "All Files".
	Fl_Native_File_Chooser (int val=BROWSE_FILE)
	The constructor. More...
int	options () const
	Gets the platform specific Fl_Native_File_Chooser::Option flags.
void	options (int o)
	Sets the platform specific chooser options to val. More...
const char *	preset_file () const
	Get the preset filename.
void	preset_file (const char *f)
	Sets the default filename for the chooser. More...
int	show ()
	Post the chooser's dialog. More...
const char *	title () const
	Get the title of the file chooser's dialog window. More...
void	title (const char *t)
	Set the title of the file chooser's dialog window. More...
int	type () const
	Gets the current Fl_Native_File_Chooser::Type of browser.
void	type (int t)
	Sets the current Fl_Native_File_Chooser::Type of browser.
	~Fl_Native_File_Chooser ()
	Destructor. More...

Static Public Attributes
static const char *	file_exists_message = "File exists. Are you sure you want to overwrite?"
	Localizable message.

Detailed Description

This class lets an FLTK application easily and consistently access the operating system's native file chooser.

Some operating systems have very complex and specific file choosers that many users want access to specifically, instead of FLTK's default file chooser(s).

In cases where there is no native file browser, FLTK's own file browser is used instead.

To use this widget, use the following include in your code:

#include <FL/Fl_Native_File_Chooser.H>

The following example shows how to pick a single file:

// Create and post the local native file chooser
#include <FL/Fl_Native_File_Chooser.H>
[..]
Fl_Native_File_Chooser fnfc;
fnfc.title("Pick a file");
fnfc.type(Fl_Native_File_Chooser::BROWSE_FILE);
fnfc.filter("Text\t*.txt\n"
            "C Files\t*.{cxx,h,c}");
fnfc.directory("/var/tmp");           // default directory to use
// Show native chooser
switch ( fnfc.show() ) {
  case -1: printf("ERROR: %s\n", fnfc.errmsg());    break;  // ERROR
  case  1: printf("CANCEL\n");                      break;  // CANCEL
  default: printf("PICKED: %s\n", fnfc.filename()); break;  // FILE CHOSEN
}

The Fl_Native_File_Chooser widget transmits UTF-8 encoded filenames to its user. It is recommended to open files that may have non-ASCII names with the fl_fopen() or fl_open() utility functions that handle these names in a cross-platform way (whereas the standard fopen()/open() functions fail on the Windows platform to open files with a non-ASCII name).

Platform Specific Caveats

• Under X11/Wayland the dialog is chosen as follows:

1. If command zenity is available at run-time and if Fl::option(OPTION_FNFC_USES_ZENITY) is turned on, the zenity -based dialog opens. This is expected to be more appropriate than other dialog forms for sandboxed apps, but member function filter_value() is not effective.
2. Else if the app runs under the KDE desktop and if Fl::option(OPTION_FNFC_USES_KDIALOG) is turned on, and if command kdialog is available at run-time, the kdialog -based dialog opens. Member function filter_value() is not effective with this dialog.
3. Else if the GTK library is available at run-time on the computer and if Fl::option(OPTION_FNFC_USES_GTK) is not turned off, the GTK-styled dialog opens. Call fl_register_images() to add a "Preview" button to this dialog. Use the static public attributes of class Fl_File_Chooser to localize the browser.
4. Otherwise, FLTK's own dialog produced by the Fl_File_Chooser class opens. Call fl_register_images() to add a "Preview" button to it. It's best if you also call Fl_File_Icon::load_system_icons() at the start of main(), to enable the nicer looking file browser widgets. Use the static public attributes of class Fl_File_Chooser to localize the browser.

• Some operating systems support certain OS specific options; see Fl_Native_File_Chooser::options() for a list.

The Fl_Native_File_Chooser on different platforms.

Member Enumeration Documentation

Option

enum Fl_Native_File_Chooser::Option

Enumerator
NO_OPTIONS	no options enabled
SAVEAS_CONFIRM	Show native 'Save As' overwrite confirm dialog.
NEW_FOLDER	Show 'New Folder' icon (if supported)
PREVIEW	enable preview mode (if supported)
USE_FILTER_EXT	Chooser filter presets the output file extension (if supported)

Type

enum Fl_Native_File_Chooser::Type

Enumerator
BROWSE_FILE	browse files (lets user choose one file)
BROWSE_DIRECTORY	browse directories (lets user choose one directory)
BROWSE_MULTI_FILE	browse files (lets user choose multiple files)
BROWSE_MULTI_DIRECTORY	browse directories (lets user choose multiple directories)
BROWSE_SAVE_FILE	browse to save a file
BROWSE_SAVE_DIRECTORY	browse to save a directory

Constructor & Destructor Documentation

Fl_Native_File_Chooser()

Fl_Native_File_Chooser::Fl_Native_File_Chooser

(

int

val = BROWSE_FILE

)

The constructor.

Internally allocates the native widgets. Optional val presets the type of browser this will be, which can also be changed with type().

~Fl_Native_File_Chooser()

Fl_Native_File_Chooser::~Fl_Native_File_Chooser

(

)

Destructor.

Deallocates any resources allocated to this widget.

Member Function Documentation

count()

int Fl_Native_File_Chooser::count

(

)

const

Returns the number of filenames (or directory names) the user selected.

Example:

if ( fnfc->show() == 0 ) {
    // Print all filenames user selected
    for (int n=0; n<fnfc->count(); n++ ) {
        printf("%d) '%s'\n", n, fnfc->filename(n));
    }
}

directory()

void Fl_Native_File_Chooser::directory

(

const char *

val

)

Preset the directory the browser will show when opened.

If val is NULL, or no directory is specified, the chooser will attempt to use the last non-cancelled folder.

errmsg()

const char * Fl_Native_File_Chooser::errmsg

(

)

const

Returns a system dependent error message for the last method that failed.

This message should at least be flagged to the user in a dialog box, or to some kind of error log. Contents will be valid only for methods that document errmsg() will have info on failures.

filename() [1/2]

const char * Fl_Native_File_Chooser::filename

(

)

const

Return the filename the user chose.

Use this if only expecting a single filename. If more than one filename is expected, use filename(int) instead. Return value may be "" if no filename was chosen (eg. user cancelled).

filename() [2/2]

const char * Fl_Native_File_Chooser::filename

(

int

i

)

const

Return one of the filenames the user selected.

Use count() to determine how many filenames the user selected.

Example:

if ( fnfc->show() == 0 ) {
    // Print all filenames user selected
    for (int n=0; n<fnfc->count(); n++ ) {
        printf("%d) '%s'\n", n, fnfc->filename(n));
    }
}

filter() [1/2]

const char * Fl_Native_File_Chooser::filter

(

)

const

Returns the filter string last set.

Can be NULL if no filter was set.

filter() [2/2]

void Fl_Native_File_Chooser::filter

(

const char *

f

)

Sets the filename filters used for browsing.

The default is NULL, which browses all files.

The filter string can be any of:

• A single wildcard (eg. "*.txt")
• Multiple wildcards (eg. "*.{cxx,h,H}")
• A descriptive name followed by a "\t" and a wildcard (eg. "Text Files\t*.txt")
• A list of separate wildcards with a "\n" between each (eg. "*.{cxx,H}\n*.txt")
• A list of descriptive names and wildcards (eg. "C++ Files\t*.{cxx,H}\nTxt Files\t*.txt")

The format of each filter is a wildcard, or an optional user description followed by '\t' and the wildcard.

On most platforms, each filter is available to the user via a pulldown menu in the file chooser. The 'All Files' option is always available to the user.

filter_value() [1/2]

int Fl_Native_File_Chooser::filter_value

(

)

const

Returns which filter value was last selected by the user.

This is only valid if the chooser returns success and if the particular file chooser supports it. Otherwise the value is not changed.

Some "native" file choosers don't support returning the filter selection by the user, particularly the system dialog based browsers:

• kdialog (KDE system dialog)
• zenity (another system dialog based chooser).

Note: this list may not be complete.

These system file chooser dialogs don't return the filter value chosen by the user.

See also

filter(const char *f)

filter_value() [2/2]

void Fl_Native_File_Chooser::filter_value

(

int

i

)

Sets which filter will be initially selected.

The first filter is indexed as 0. If filter_value() == filters(), then "All Files" was chosen. If filter_value() > filters(), then a custom filter was set.

Some "native" file choosers don't support this way to set the initial filter type, particularly the system dialog based browsers:

• kdialog (KDE system dialog)
• zenity (another system dialog based chooser).

Note: this list may not be complete.

As far as we know these dialogs use the first item in the list of filter values as the initial filter presented to the user.

See also

filter(const char *f)

options()

void Fl_Native_File_Chooser::options

(

int

o

)

Sets the platform specific chooser options to val.

val is expected to be one or more Fl_Native_File_Chooser::Option flags ORed together. Some platforms have OS-specific functions that can be enabled/disabled via this method.

Flag              Description                                       Win       Mac       Other
--------------    -----------------------------------------------   -------   -------   -------
NEW_FOLDER        Shows the 'New Folder' button.                    Ignored   Used      Used
PREVIEW           Enables the 'Preview' mode by default.            Ignored   Ignored   Used
SAVEAS_CONFIRM    Confirm dialog if BROWSE_SAVE_FILE file exists.   Used      Used      Used
USE_FILTER_EXT    Chooser filter presets the output file extension. Ignored   Used      Used (GTK)

preset_file()

void Fl_Native_File_Chooser::preset_file

(

const char *

f

)

Sets the default filename for the chooser.

Use directory() to set the default directory. Mainly used to preset the filename for save dialogs, and on most platforms can be used for opening files as well.

show()

int Fl_Native_File_Chooser::show

(

)

Post the chooser's dialog.

Blocks until dialog has been completed or cancelled.

Returns

• 0 – user picked a file
• 1 – user cancelled
• -1 – failed; errmsg() has reason

title() [1/2]

const char * Fl_Native_File_Chooser::title

(

)

const

Get the title of the file chooser's dialog window.

Return value may be NULL if no title was set.

title() [2/2]

void Fl_Native_File_Chooser::title

(

const char *

t

)

Set the title of the file chooser's dialog window.

Can be NULL if no title desired. The default title varies according to the platform, so you are advised to set the title explicitly.

---

The documentation for this class was generated from the following files:

• Fl_Native_File_Chooser.H
• Fl_Native_File_Chooser.cxx
• Fl_Native_File_Chooser_GTK.cxx