fltk/examples/nativefilechooser-simple-app.cxx

//
//      An example of how to use Fl_Native_File_Chooser to open & save files.
//
// Copyright 2010 Greg Ercolano.
// Copyright 1998-2017 by Bill Spitzak and others.
//
// This library is free software. Distribution and use rights are outlined in
// the file "COPYING" which should have been included with this file.  If this
// file is missing or damaged, see the license at:
//
//     https://www.fltk.org/COPYING.php
//
// Please see the following page on how to report bugs and issues:
//
//     https://www.fltk.org/bugs.php
//
#include <stdio.h>      // printf
#include <stdlib.h>     // exit,malloc
#include <string.h>     // strerror
#include <errno.h>      // errno
#include <FL/Fl.H>
#include <FL/Fl_Window.H>
#include <FL/Fl_Menu_Bar.H>
#include <FL/Fl_Native_File_Chooser.H>
#include <FL/Fl_Box.H>
#include <FL/fl_ask.H>

class Application : public Fl_Window {
  Fl_Native_File_Chooser *fc;
  // Does file exist?
  int exist(const char *filename) {
    FILE *fp = fl_fopen(filename, "r");
    if (fp) { fclose(fp); return(1); }
    else    { return(0); }
  }
  // 'Open' the file
  void open(const char *filename) {
    printf("Open '%s'\n", filename);
  }
  // 'Save' the file
  //    Create the file if it doesn't exist
  //    and save something in it.
  //
  void save(const char *filename) {
    printf("Saving '%s'\n", filename);
    if ( !exist(filename) ) {
      FILE *fp = fl_fopen(filename, "w"); // create file if it doesn't exist
      if ( fp ) {
        // A real app would do something useful here.
        fprintf(fp, "Hello world.\n");
        fclose(fp);
      } else {
        fl_message("Error: %s: %s", filename, strerror(errno));
      }
    } else {
      // A real app would do something useful here.
    }
  }
  // Handle an 'Open' request from the menu
  static void open_cb(Fl_Widget *w, void *v) {
    Application *app = (Application*)v;
    app->fc->title("Open");
    app->fc->type(Fl_Native_File_Chooser::BROWSE_FILE);         // only picks files that exist
    switch ( app->fc->show() ) {
      case -1: break;   // Error
      case  1: break;   // Cancel
      default:          // Choice
        app->fc->preset_file(app->fc->filename());
        app->open(app->fc->filename());
        break;
    }
  }
  // Handle a 'Save as' request from the menu
  static void saveas_cb(Fl_Widget *w, void *v) {
    Application *app = (Application*)v;
    app->fc->title("Save As");
    app->fc->type(Fl_Native_File_Chooser::BROWSE_SAVE_FILE);    // need this if file doesn't exist yet
    switch ( app->fc->show() ) {
      case -1: break;   // Error
      case  1: break;   // Cancel
      default:          // Choice
        app->fc->preset_file(app->fc->filename());
        app->save(app->fc->filename());
        break;
    }
  }
  // Handle a 'Save' request from the menu
  static void save_cb(Fl_Widget *w, void *v) {
    Application *app = (Application*)v;
    if ( strlen(app->fc->filename()) == 0 ) {
      saveas_cb(w,v);
    } else {
      app->save(app->fc->filename());
    }
  }
  static void quit_cb(Fl_Widget *w, void *v) {
    exit(0);
  }
  // Return an 'untitled' default pathname
  const char* untitled_default() {
    static char *filename = 0;
    if ( !filename ) {
      const char *home =
        fl_getenv("HOME") ? fl_getenv("HOME") :            // unix
        fl_getenv("HOME_PATH") ? fl_getenv("HOME_PATH") :  // windows
        ".";                                               // other
      filename = (char*)malloc(strlen(home)+20);
      sprintf(filename, "%s/untitled.txt", home);
    }
    return(filename);
  }
public:
  // CTOR
  Application() : Fl_Window(400,200,"Native File Chooser Example") {
    Fl_Menu_Bar *menu = new Fl_Menu_Bar(0,0,400,25);
    menu->add("&File/&Open",  FL_COMMAND+'o', open_cb, (void*)this);
    menu->add("&File/&Save",  FL_COMMAND+'s', save_cb, (void*)this);
    menu->add("&File/&Save As", 0,  saveas_cb, (void*)this);
    menu->add("&File/&Quit",  FL_COMMAND+'q', quit_cb);
    // Describe the demo..
    Fl_Box *box = new Fl_Box(20,25+20,w()-40,h()-40-25);
    box->color(45);
    box->box(FL_FLAT_BOX);
    box->align(FL_ALIGN_CENTER|FL_ALIGN_INSIDE|FL_ALIGN_WRAP);
    box->label("This demo shows an example of implementing "
               "common 'File' menu operations like:\n"
               "    File/Open, File/Save, File/Save As\n"
               "..using the Fl_Native_File_Chooser widget.\n\n"
               "Note 'Save' and 'Save As' really *does* create files! "
               "This is to show how behavior differs when "
               "files exist vs. do not.");
    box->labelsize(12);
    // Initialize the file chooser
    fc = new Fl_Native_File_Chooser();
    fc->filter("Text\t*.txt\n");
    fc->preset_file(untitled_default());
    end();
  }
};

int main(int argc, char *argv[]) {
  Fl::scheme("gtk+");
  Application *app = new Application();
  app->show(argc,argv);
  return(Fl::run());
}