Using the FL_File_Chooser widget

maveganzones · #1 07-Apr-2005, 12:27

Hi all, this widget its wonderfull but hard to use. This is how i use it and what problems i havent fixed.

CPP / C++ / C Code:

// The FL_File_Chooser is a subclass of Fl_Group so it can be used like the Fl_Group.
Fl_File_Chooser* fc = new Fl_File_Chooser(".","Image Files (*.{bmp,gif,jpg,png})",Fl_File_Chooser::SINGLE,"Imagen:");
fc->callback(cb_fc);

// ...

// Now the callback
void cb_fc(Fl_File_Chooser* o, void* v) {
// your code
String filename = o -> value();
}

Problem 1: Fl_File_Chooser dosn't implement end() or parent() methods so you can't call the parent from the static callback. This restringes a lot the use of the widget.
Solution: making the parent singleton.

Problem 2: the callback event gets up when you select a file in the browser. This is a little weird. The normal use its to do something when the user push the OK button.
Solution 2: i dont know yet. I dont know how to do it.

The FLTK documentation gives some guidelines to create the Fl_File_Chooser object because the constructor its different from the rest. Take a look at it.

Can anyone give a response to the problem two?

Greetings.

maveganzones · #2 08-Apr-2005, 12:07

In adition to problem 1: i have read in another http://www.gidforums.com/t-4743.html that the void *v param in the callback can convert to the class containing the widget (this is valid for all the widgets not only the Fl_File_Chooser):

CPP / C++ / C Code:

//the callback associated to a widget
void cb_fc(Fl_File_Chooser* o, void* v) {
// your code cant use the class methods and variables
((TheClass*)v)->callback(o); // calling a method of your class
}

void TheClass::callback(Fl_File_Chooser* o) {
//do whatever
String filename = o -> value(); //using the file name
...
}

Now I dont need the singleton pattern to make it works.

Dimas · #3 14-Apr-2005, 17:58

Quote:

Originally Posted by maveganzones

Hi all, this widget its wonderfull but hard to use. This is how i use it and what problems i havent fixed.

Problem 2: the callback event gets up when you select a file in the browser. This is a little weird. The normal use its to do something when the user push the OK button.
Solution 2: i dont know yet. I dont know how to do it.

I had the same problem, I mean, I wanted to do something only when OK button was pressed! What I did:

CPP / C++ / C Code:

// The FL_File_Chooser is a subclass of Fl_Group so it can be used like the Fl_Group.
Fl_File_Chooser* fc = new Fl_File_Chooser(".","Image Files (*.{bmp,gif,jpg,png})",Fl_File_Chooser::SINGLE,"Imagen:");

// Maybe you don't want to have a file_chooser callback
/*  
fc->callback(cb_fc);

// ...


// Now the callback
void cb_fc(Fl_File_Chooser* o, void* v) {
// your code 
String filename = o -> value();
}
*/

// ....

// Now call the file chooser ...
fc->show();
// ... them make FL wait until the file selection is done
while(fc->shown())
      Fl::wait();
// finally manipulate the file name
String filename = fc -> value();

Hope it works for your problem.

maveganzones · #4 18-Apr-2005, 10:48

it works really good, thx

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Using the FL_File_Chooser widget

About problem 2