swapping image of gtk button

[681ankit]

I am creating a program in which ,there are two buttons ,when these two buttons are clicked one after other ,it will swap the image assign to these buttons..Can't find way ..
** But I'm getting error :

GLib-GObject-CRITICAL **: g_object_ref: assertion `G_IS_OBJECT (object)' failed


code is:-

<code>
#include<gtk/gtk.h>
#include<stdio.h>


static GtkWidget *prev_b; // previous button click stored here
static GtkWidget *prev_i; // previuos button's image
static int count=0; //distinguish between two button's click

static void on_click(GtkWidget * button, GtkWidget *b);
int main(int argc , char *argv[])
{

GtkWidget * window;
GtkWidget *button1,*button2;
GtkWidget *img1,*img2,*temp;
GtkWidget * hbox;

gtk_init(&argc,&argv);



window=gtk_window_new(GTK_WINDOW_TOPLEVEL);
hbox=gtk_hbox_new(TRUE,5);

button1=gtk_button_new_with_label("");
button2=gtk_button_new_with_label("");

img1=gtk_image_new_from_file("img/other/h6.png");
img2=gtk_image_new_from_file("img/other/h7.png");
temp=gtk_image_new_from_file("img/other/temp.png");


gtk_button_set_image(GTK_BUTTON(button1),img1);
gtk_button_set_image(GTK_BUTTON(button2),img2);
gtk_box_pack_start_defaults(GTK_BOX(hbox),button1) ;
gtk_box_pack_start_defaults(GTK_BOX(hbox),button2) ;



gtk_container_add(GTK_CONTAINER(window),hbox);
gtk_widget_show_all(window);
gtk_widget_show(img1);
gtk_widget_show(img2);
gtk_widget_show(temp);





g_signal_connect(G_OBJECT(button1),"clicked",G_CAL LBACK(on_click),img1);
g_signal_connect(G_OBJECT(button2),"clicked",G_CAL LBACK(on_click),img2);
g_signal_connect(G_OBJECT(window), "destroy",G_CALLBACK(gtk_main_quit), NULL);


gtk_main();

return 0;
}




static void on_click(GtkWidget * button, GtkWidget *img)
{


if(count==1)
{
count=count-1;
if(prev_i==img)return;
else
{
gtk_button_set_image(GTK_BUTTON(button),prev_i);//setting image to current button
gtk_button_set_image(GTK_BUTTON(prev_b),img); //setting image to prev button
}
return ;
}
if(count==0)
{
count=count+1;
prev_b=button;
prev_i=img;
return ;
}




}

</code>

[mali2297]

I believe the problem is that the button takes ownership of the image when you call gtk_button_set_image. Then, when you replace the image with a new call to the same function, the old image is destroyed.

As a solution, increase the reference count of the image objects after their creation:

img1=gtk_image_new_from_file("img/other/h6.png");
img2=gtk_image_new_from_file("img/other/h7.png");

g_object_ref (img1);
g_object_ref (img2);

gtk_button_set_image(GTK_BUTTON(button1),img1);
gtk_button_set_image(GTK_BUTTON(button2),img2);

Ideally, you should also unref them when you are finished using them.