GTK+ Use one handler for multiple widgets - c++

Question

I have a callback function as follows:
void handle(GtkWidget *widget, gpointer data) {...}
Since I have a lot of widgets for this window, I would like to use this callback as the only handler to avoid writing a bunch of small functions. Initially I thought of using an enum that's stored in the UI class which wraps around the window, and then I would test for it as follows:
UIClass::Signal signal = (UIClass::Signal) data;
switch (signal) {
case UIClass::main_button:
// handle
case UIClass::check_box:
...
}
But the compiler refuses the cast in the first line of that snippet.
Is there a standard way to accomplish this? Or was GTK+ designed to have one handler for every widget?

Answer 1

Store a pointer to a widget in class and pass whole object to the handler:
#include <gtk/gtk.h>
#include <iostream>
struct UIClass
{
GtkWidget* widget1, *widget2, *box;
UIClass()
{
widget1 = gtk_button_new_with_label("button1");
widget2 = gtk_button_new_with_label("button2");
box = gtk_hbox_new(true, 10);
gtk_box_pack_start(GTK_BOX(box), widget1, 0 ,0, 1);
gtk_box_pack_start(GTK_BOX(box), widget2, 0 ,0, 1);
}
static void handle(GtkWidget* sender, UIClass* uiClass)
{
if(sender == uiClass->widget1)
std::cout<<"widget1"<<std::endl;
else if(sender == uiClass->widget2)
std::cout<<"widget2"<<std::endl;
else
std::cout<<"something else"<<std::endl;
}
void connect()
{
g_signal_connect(widget1, "clicked", G_CALLBACK(UIClass::handle), this);
g_signal_connect(widget2, "clicked", G_CALLBACK(UIClass::handle), this);
}
};
int main(int argc, char *argv[])
{
gtk_init (&argc, &argv);
GtkWidget* window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
UIClass ui;
ui.connect();
gtk_container_add(GTK_CONTAINER(window), ui.box);
gtk_widget_show_all(window);
gtk_main();
return 0;
}