Re: Updating TextView and StatusBar problem

[Miguel Figueiredo <olliegator hortanet com>]

Hi Peter,

I followed your thread suggestion, and this code seems to work properly.
I hope that this can be of help for other people :)

Thanks.

Miguel

#include <stdio.h>
#include <unistd.h>
#include <gtk/gtk.h>
#include <pthread.h>

/* Aux data type */
typedef struct WINDOW{
        GtkWidget *window;
        GtkWidget *textview;
        GtkWidget *statusbar;
}windowT;

/* Prints something in status bar */
void print_statusbar (char *string, GtkStatusbar  *statusbar){
  
  gtk_statusbar_pop (statusbar, 0);

  gtk_statusbar_push (statusbar, 0, string);
}

/* Prints something in textview */
void print_textview(char *string, GtkTextView *textview){
        GtkTextBuffer *buffer;

        buffer = gtk_text_view_get_buffer (textview);
        
        gtk_text_buffer_insert_at_cursor(buffer, string, -1);
}

/* Thread func */
void *thread_func(void *args){
        windowT *window = (windowT*)args;
        
        gdk_threads_enter();
        print_textview("BLA\n", GTK_TEXT_VIEW(window->textview));
        print_statusbar(" Just printed BLA", GTK_STATUSBAR(window->statusbar));
        gdk_threads_leave();

        sleep(1);

        gdk_threads_enter();
        print_textview("BLE\n", GTK_TEXT_VIEW(window->textview));
        print_statusbar(" Just printed BLE", GTK_STATUSBAR(window->statusbar));
        gdk_threads_leave();
        
        return NULL;
}

/* Callback function */
void my_func(GtkButton *button, windowT *window){
        pthread_t tid;

        pthread_create(&tid, NULL, thread_func, window);
}


/* Main window */
windowT *create_window(){
        windowT *window;
        GtkWidget *vbox, *button;

        /* Main window */
        window->window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
        gtk_window_set_default_size (GTK_WINDOW (window->window),450, 450);
        g_signal_connect (window->window, "destroy",G_CALLBACK (gtk_main_quit),NULL);

        /* Vertical box */
        vbox = gtk_vbox_new(FALSE,0);
        gtk_container_add(GTK_CONTAINER(window->window), vbox);
        gtk_widget_show(vbox);

        /* Text view */
        window->textview = gtk_text_view_new();
        gtk_box_pack_start(GTK_BOX(vbox), window->textview, TRUE, TRUE, 0);
        gtk_text_view_set_editable (GTK_TEXT_VIEW (window->textview), FALSE);
        gtk_text_view_set_cursor_visible (GTK_TEXT_VIEW (window->textview), FALSE);
        gtk_widget_show(window->textview);

        /* Button */
        button = gtk_button_new_with_label("BUTTON");
        gtk_widget_show(button);
        gtk_box_pack_start(GTK_BOX(vbox), button, FALSE,FALSE, 0);
        g_signal_connect(GTK_OBJECT(button), "clicked", GTK_SIGNAL_FUNC(my_func), 
window);

        /* Status bar */
        window->statusbar = gtk_statusbar_new();
        gtk_box_pack_start(GTK_BOX(vbox), window->statusbar, FALSE, FALSE, 0);
        gtk_widget_show(window->statusbar);

        return(window);
}

/* No comments ;) */
int main( int   argc,  char *argv[] ){
        windowT *window;
        
        g_thread_init(NULL);
        gdk_threads_init();     
        gtk_init (&argc, &argv);

        window = create_window();

        gtk_widget_show(window->window);

        gdk_threads_enter();
        gtk_main ();
        gdk_threads_leave();

        return(0);
}



On Monday 05 April 2004 10:16, Peter Krueger wrote:
> On Sat, 3 Apr 2004, Miguel Figueiredo wrote:
> > I created a window which has a textview, a button and a statusbar. When I
> > press the button, I want to call a func that inserts text in both the
> > textview and the statusbar over a certain amount of time. The problem is
> > that this text is only visible when the function ends. The purpose is to
> > display the text as soon as it is inserted in the textview and/or
> > statusbar.
>
> Hi Miguel,
> GTK does its user interface updates in the main loop. When you press the
> button the mainloop does not run until your event handler returns, that's
> why you don't see the updates of your text changes. To overcome this you
> can use
>     while (gtk_events_pending()) {
>       gtk_main_iteration();
>     }
> after you changed texts but before the time consuming task. When you
> enter your callback you should call gtk_widget_set_sensitive(button,
> false) to prevent that the user presses the button again before its first
> event handling is finished. Right before exiting the callback enable it
> again with gtk_widget_set_sensitive(button, true).
>
> If your task is really time consuming (more than 1 second) you should do
> it in a separate thread. A program with a graphical user interface should
> always react to user input (like moving/resizing the window) and refresh
> its display e.g. after it was covered by another application. Else the
> user will think that your program crashed.
>
> Regards,
>                             Peter

-- 
Miguel Figueiredo
IT student / Marine Biologist
"If it ain't broken, don't fix it."