GTK +/C避免保留GtkGrid内隐藏小部件的空间

GtkGrid包含一些小部件。当我隐藏一些这些小部件时，仍然存在它们的空间，而我想让所有可见小部件以“自然方式”重新对齐（不保留隐藏小部件的空间）。GTK +/C避免保留GtkGrid内隐藏小部件的空间

一个小例子：

#include <gtk/gtk.h> 

GtkWidget *label2, *label3; 

static gboolean on_button_click (GtkButton *button, gpointer data) { 
    gtk_widget_hide (label2); 
    gtk_widget_hide (label3); 
    return TRUE; 
} 

int main (int argc, char **argv) { 
    gtk_init(&argc, &argv); 
    GtkWidget *window; 
    GtkWidget *label1 = gtk_label_new("Widget1"); 
    label2 = gtk_label_new("Widget2"); 
    label3 = gtk_label_new("Widget3"); 
    GtkWidget *label4 = gtk_label_new("Widget4"); 
    GtkWidget *button = gtk_button_new_with_label ("Hide widget2 and widget3"); 
    g_signal_connect(button, "clicked", G_CALLBACK (on_button_click), NULL); 

    window = gtk_window_new (GTK_WINDOW_TOPLEVEL); 
    GtkWidget *box = gtk_box_new(GTK_ORIENTATION_VERTICAL, 10); 

    GtkGrid *grid = (GtkGrid*)gtk_grid_new(); 
    gtk_grid_set_row_spacing((GtkGrid*)grid, 50); 
    gtk_grid_set_column_spacing((GtkGrid*)grid, 50); 
    // 2 columns 
    gtk_grid_insert_column (grid, 0); 
    gtk_grid_insert_column (grid, 1); 
    // 2 rows 
    gtk_grid_insert_row (grid, 0); 
    gtk_grid_insert_row (grid, 1); 

    //Add widgets to the grid 
    gtk_grid_attach(GTK_GRID(grid), label1, 1, 0, 1, 1); 
    gtk_grid_attach(GTK_GRID(grid), label2, 2, 0, 1, 1); 
    gtk_grid_attach(GTK_GRID(grid), label3, 1, 1, 1, 1); 
    gtk_grid_attach(GTK_GRID(grid), label4, 2, 1, 1, 1); 

    gtk_box_pack_start (GTK_BOX (box), button, FALSE, FALSE, 0); 
    gtk_box_pack_start (GTK_BOX (box), (GtkWidget*)grid, FALSE, FALSE, 0); 
    gtk_container_add (GTK_CONTAINER (window), box); 

    gtk_widget_show_all (window); 

    gtk_main(); 

    return 0; 
}

这个程序编译：

gcc `pkg-config --cflags gtk+-3.0` test.c `pkg-config --libs gtk+-3.0` -o test

给这个窗口：