andrei_c wrote:
> Hello, I'm trying to make a program that uses some keyboard events, so I came
> up whit a program that moves a rectangle to the right when the right arrow
> key is pressed.But it does not work.
> Here's the first version of the program:
> int Canvas::handle(int event) // handle the event
> {
> switch(event)
> {
This must be FL_KEYBOARD, and you must call Fl::event_key() to get the
key value.
> case FL_Right:
> XC = XC + 1;
> YC = YC + 1;
> redraw();
> return 1;
> default:
> return Fl_Box::handle(event);
> }
> }
>
> /**************************************************************************/
> int main()
> {
> Fl_Double_Window *my_win = new Fl_Double_Window(300,300, "Draw animation");
> my_win->begin();
>
> Canvas my_canvas(20,20,260,260,0);
>
> my_win->resizable(my_canvas);
> my_win->end();
> my_win->show();
>
> return Fl::run();
> }
> /**************************************************************************/
>
> When I pres the right arrow key it does nothing.
>
> But reading some tutorials I came up whit another version:
[...]
> This doesn't work either.
> One question: should I use only the handle() overrided function to handle all
> events, including keyboard, or should I do it like the second version??Whit a
> special function for keyboard.
> Please help me if you have the time, I know I am close, but still not quite
> there.
There's no need to write a function that handles only key events, the
first version would do it as well, but there are some problems.
There is no event named Fl_Right. You must handle FL_KEYBOARD events and
use Fl::event_key() to get the key value (the second version does this
correctly).
To get key events your widget must return 1 on FL_PUSH and FL_FOCUS
events. I don't think that Fl_Box::handle() would do this, so you'd
better add this in your handle() method. Then you must click once in
your canvas, and your widget should get key events.
For a start you could try to set Fl::focus(my_canvas) before calling
Fl::run().
Another trick would be to handle FL_SHORTCUT events. They are basically
the same as FL_KEYBOARD events, but they are delivered to all widgets,
if no widget handles the FL_KEYBOARD event. However, I wouldn't
recommend this for real applications.
Albrecht
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