Trying to learn Linux development out of curiosity with little knowledge of C.
I am using glade 3.18.3.
I want to create an application in which the text on label1 will be changed with the input text in entry1 (input box) when button1 will be pressed.
I do not know how to pass the needed arguments to the callback.
This is sample.glade:
<?xml version="1.0" encoding="UTF-8"?>
<!-- Generated with glade 3.18.3 -->
<interface>
<requires lib="gtk+" version="3.12"/>
<object class="GtkWindow" id="window_main">
<property name="can_focus">False</property>
<property name="title" translatable="yes">Nishant</property>
<property name="default_width">440</property>
<property name="default_height">250</property>
<signal name="destroy" handler="on_window_main_destroy" swapped="no"/>
<child>
<object class="GtkBox" id="box1">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="orientation">vertical</property>
<child>
<object class="GtkMenuBar" id="menubar1">
<property name="visible">True</property>
<property name="can_focus">False</property>
<child>
<object class="GtkMenuItem" id="menuitem1">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="label" translatable="yes">_File</property>
<property name="use_underline">True</property>
<child type="submenu">
<object class="GtkMenu" id="menu1">
<property name="visible">True</property>
<property name="can_focus">False</property>
<child>
<object class="GtkImageMenuItem" id="imagemenuitem1">
<property name="label">gtk-new</property>
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="use_underline">True</property>
<property name="use_stock">True</property>
</object>
</child>
<child>
<object class="GtkImageMenuItem" id="imagemenuitem2">
<property name="label">gtk-open</property>
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="use_underline">True</property>
<property name="use_stock">True</property>
</object>
</child>
<child>
<object class="GtkImageMenuItem" id="imagemenuitem3">
<property name="label">gtk-save</property>
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="use_underline">True</property>
<property name="use_stock">True</property>
</object>
</child>
<child>
<object class="GtkImageMenuItem" id="imagemenuitem4">
<property name="label">gtk-save-as</property>
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="use_underline">True</property>
<property name="use_stock">True</property>
</object>
</child>
<child>
<object class="GtkSeparatorMenuItem" id="separatormenuitem1">
<property name="visible">True</property>
<property name="can_focus">False</property>
</object>
</child>
<child>
<object class="GtkImageMenuItem" id="imagemenuitem5">
<property name="label">gtk-quit</property>
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="use_underline">True</property>
<property name="use_stock">True</property>
</object>
</child>
</object>
</child>
</object>
</child>
<child>
<object class="GtkMenuItem" id="menuitem2">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="label" translatable="yes">_Edit</property>
<property name="use_underline">True</property>
<child type="submenu">
<object class="GtkMenu" id="menu2">
<property name="visible">True</property>
<property name="can_focus">False</property>
<child>
<object class="GtkImageMenuItem" id="imagemenuitem6">
<property name="label">gtk-cut</property>
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="use_underline">True</property>
<property name="use_stock">True</property>
</object>
</child>
<child>
<object class="GtkImageMenuItem" id="imagemenuitem7">
<property name="label">gtk-copy</property>
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="use_underline">True</property>
<property name="use_stock">True</property>
</object>
</child>
<child>
<object class="GtkImageMenuItem" id="imagemenuitem8">
<property name="label">gtk-paste</property>
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="use_underline">True</property>
<property name="use_stock">True</property>
</object>
</child>
<child>
<object class="GtkImageMenuItem" id="imagemenuitem9">
<property name="label">gtk-delete</property>
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="use_underline">True</property>
<property name="use_stock">True</property>
</object>
</child>
</object>
</child>
</object>
</child>
<child>
<object class="GtkMenuItem" id="menuitem3">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="label" translatable="yes">_View</property>
<property name="use_underline">True</property>
</object>
</child>
<child>
<object class="GtkMenuItem" id="menuitem4">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="label" translatable="yes">_Help</property>
<property name="use_underline">True</property>
<child type="submenu">
<object class="GtkMenu" id="menu3">
<property name="visible">True</property>
<property name="can_focus">False</property>
<child>
<object class="GtkImageMenuItem" id="imagemenuitem10">
<property name="label">gtk-about</property>
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="use_underline">True</property>
<property name="use_stock">True</property>
</object>
</child>
</object>
</child>
</object>
</child>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">True</property>
<property name="position">0</property>
</packing>
</child>
<child>
<object class="GtkLabel" id="label1">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="label" translatable="yes">label1</property>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">True</property>
<property name="position">1</property>
</packing>
</child>
<child>
<object class="GtkEntry" id="entry1">
<property name="name">entry1</property>
<property name="visible">True</property>
<property name="can_focus">True</property>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">True</property>
<property name="position">2</property>
</packing>
</child>
<child>
<object class="GtkButton" id="button1">
<property name="label" translatable="yes">button1</property>
<property name="name">button1</property>
<property name="visible">True</property>
<property name="can_focus">True</property>
<property name="receives_default">True</property>
<property name="halign">center</property>
<signal name="activate" handler="on_button1_activate" swapped="no"/>
<signal name="clicked" handler="on_button1_clicked" swapped="no"/>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">True</property>
<property name="position">3</property>
</packing>
</child>
<child>
<object class="GtkStatusbar" id="statusbar1">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="margin_left">10</property>
<property name="margin_right">10</property>
<property name="margin_start">10</property>
<property name="margin_end">10</property>
<property name="margin_top">6</property>
<property name="margin_bottom">6</property>
<property name="orientation">vertical</property>
<property name="spacing">2</property>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">True</property>
<property name="position">4</property>
</packing>
</child>
</object>
</child>
</object>
</interface>
...and this is main.c:
//##gcc -o gladewin main.c -Wall pkg-config --cflags --libs gtk+-3.0 -export-dynamic
#include <gtk/gtk.h>
#include <stdio.h>
//gchar *buffer1; //added
int main(int argc, char *argv[])
{
GtkBuilder *builder;
GtkWidget *window;
// ## gchar BUFF[100];
gtk_init(&argc, &argv);
builder = gtk_builder_new();
gtk_builder_add_from_file (builder, "sample.glade", NULL);
window = GTK_WIDGET(gtk_builder_get_object(builder, "window_main"));
gtk_builder_connect_signals(builder, NULL);
g_object_unref(builder);
gtk_widget_show(window);
gtk_main();
return 0;
}
// called when window is closed
void on_window_main_destroy()
{
gtk_main_quit();
}
//called when button1 is clicked
void on_button1_clicked()
{
//buffer1 = gtk_entry_get_buffer (entry);
//gtk_entry_buffer_get_text (buffer1);
g_print("Button1 pressed");
//gtk_button_set_label (button1 ,"Hi");
//gtk_label_set_text(GTK_LABEL(entry1),"hi"); // i think this is correct just need tofigure out what to replace insted of entry1
}
The signal callbacks receive specific arguments depending on the type of signal caught. The signature of every callback is documented by the official documentation.
In glade, when defining a signal, you can pass an additional widget to the signal callback. The real challenge is that you can pass only one widget, while you need to have access to both of them (the label and the entry).
In plain C you will stuff the two pointers into one struct and use that instead but if you still want to use glade you must find another solution. A way could be to use two callbacks, e.g.:
Then your callbacks could be:
void read_from_entry(GtkButton *button, gpointer user_data)
{
GtkEntry *entry = GTK_ENTRY(user_data);
g_print("read_from_entry\n");
g_object_set_data(G_OBJECT(button), "text", (gpointer) gtk_entry_get_text(entry));
}
void write_to_label(GtkButton *button, gpointer user_data)
{
GtkLabel *label = GTK_LABEL(user_data);
g_print("write_to_label\n");
gtk_label_set_text(label, g_object_get_data(G_OBJECT(button), "text"));
}
The g_object_{set,get}_data pair is used just to avoid using a global. The above will work reliably provided that: