in reply to Curses::UI loop dilemma

From the source:

    # Read a key or use the feeded key.
    my $key = $this->{-feedkey};
    unless (defined $key) {
        $key = $this->get_key($this->{-read_timeout});
    }
    $this->{-feedkey} = undef;

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From Curses::UI::Common (one of Curses::UI's base classes],

get_key ( BLOCKTIME, CURSOR )

...

The BLOCKTIME argument can be used to set the curses halfdelay (the time to wait before the routine decides that no key was pressed). BLOCKTIME is given in tenths of seconds. The default is 0 (non-blocking key read).

So pass -read_timeout => 0 to Curses::UI's constructor.

Note: -mouse_support => 1 overrides -read_timeout with a value of 2.5 seconds. You could override that in turn using $cui->{-read_timeout} = 0, but I don't know what effect that will have on mouse support.

(Untested.)

Replies are listed 'Best First'.
Re^2: Curses::UI loop dilemma
by Anonymous Monk on Sep 18, 2005 at 10:47 UTC
    Thanks for the answer, it looked very promising, but unfortunately that doesn't change anything... do_one_event() still waits for a keypress, although the timeout was set to 0 and 1, for testing.

    My program works flawlessly when I keep my finger on the arrow-down key for example, but once I stop nothing gets updated anymore, because that damn function doesn't return.

    Any other ideas?

    If this doesn't work I have to use the backup version of that program, where I wrote the UI handling myself.. badly hacked together, but at least that worked...
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Re^2: Curses::UI loop dilemma
by Anonymous Monk on Sep 18, 2005 at 20:23 UTC
    Ah, it works now!
    Somehow, $cui->{-read_timeout} was -1, although it shouldn't be. So I changed it directly to 0, et voila, it doesn't wait for a key press anymore. :)
    Thanks, ikegami.
[reply]

      Hi, I'm trying to do something similar to this. I am using Curses::UI to implement a ticket like system where new tickets comes in from users via UDP and it will update the Curses:UI:Listbox.

      I tried to take the same route and and rather than using the $cui->mainloop(); from Curses:UI, I put it into my own server so that it can update the UI without blocking. But it seems when I do that, I lose the Curses:UI listbox functionality of having a scrollbox, being able to move up/down the list, etc; since everytime I try to run doupdate(); when a new UDP comes in, the program exits... 

      #!/usr/bin/perl

use strict;
use warnings;
use IO::Socket;
use Curses::UI;

my ($sock, $data, $clienthost, $maxlen, $port);

$maxlen = 1024;
$port = 3711;

my @array;

my $cui = Curses::UI->new(-mouse_support => 0,-read_timeout => 0);
my $win = $cui->add('window_id', 'Window');
my $listbox = $win->add('Tickets', 'Listbox',
        -border => 1,
        -title  => 'Items',
        -vscrollbar     => 1,
);

$cui->{-read_timeout} = 0;
$cui->set_binding( sub{ exit }, "\cQ" );
$cui->draw();

$sock = IO::Socket::INET->new(LocalPort => $port,
                                Type => SOCK_DGRAM,
                                Proto => 'udp')
                          or die "Could not open socket!\n";

while (1) {

  $cui->focus(undef, 1); # 1 = forced focus
  $sock->recv($data, $maxlen);
  chomp($data);

  my $req = $data;
  my($port, $ipaddr) = sockaddr_in($sock->peername);

  $clienthost = gethostbyaddr($ipaddr, AF_INET);

  $listbox->insert_at(\@array, "New ticket from ".$clienthost.": ".$re
+q);
  $sock->send("We have received your ticket: $req");

  $listbox->focus();
  $cui->draw;
#  doupdate();
  $cui->do_one_event();

      [download]
[reply]
[d/l]
Re^2: Curses::UI loop dilemma
by Anonymous Monk on Sep 18, 2005 at 10:53 UTC
    ... also, your description of the get_key() function said:

    The default is 0 (non-blocking key read)

    So no wonder that it doesn't change anything... it should have worked from the beginning on...
[reply]

      The default if nothing is passed to get_key is 0, but Curses::UI passes -1 (full blocking) by default.

      By the way, I just noticed -mouse_support is 1 by default, so you'll either have to pass -mouse_support => 0 to the constructor, or do $cui->{-read_timeout} = 0 (which might break mouse support).

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[d/l]
[select]
        My constructor was: 
        my $cui = Curses::UI->new(
    -mouse_support => 0,
    -read_timeout  => 0,
    -color_support => 1,
    -clear_on_exit => 1,
);

        [download]
        So that should have worked... should... :(
[reply]
[d/l]
Re^2: Curses::UI loop dilemma
by Anonymous Monk on Sep 18, 2005 at 11:31 UTC
    By the way, I also cannot use add_callback( <id>, \&some_of_my_code ) and then mainloop(), because the coderef also gets run only AFTER the input handling is done.
[reply]

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