gtk使用ui文件定义界面运行报错

今天在照着gtk的官方教程做示例的时候，遇到一个问题，就是下面的链接，https://docs.gtk.org/gtk4/getting_started.html ，

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#include <gtk/gtk.h>
#include <glib/gstdio.h>

static void
print_hello (GtkWidget *widget,
             gpointer   data)
{
  g_print ("Hello World\n");
}

static void
quit_cb (GtkWindow *window)
{
  gtk_window_close (window);
}

static void
activate (GtkApplication *app,
          gpointer        user_data)
{
  /* Construct a GtkBuilder instance and load our UI description */
  GtkBuilder *builder = gtk_builder_new ();
  gtk_builder_add_from_file (builder, "builder.ui", NULL);

  /* Connect signal handlers to the constructed widgets. */
  GObject *window = gtk_builder_get_object (builder, "window");
  gtk_window_set_application (GTK_WINDOW (window), app);

  GObject *button = gtk_builder_get_object (builder, "button1");
  g_signal_connect (button, "clicked", G_CALLBACK (print_hello), NULL);

  button = gtk_builder_get_object (builder, "button2");
  g_signal_connect (button, "clicked", G_CALLBACK (print_hello), NULL);

  button = gtk_builder_get_object (builder, "quit");
  g_signal_connect_swapped (button, "clicked", G_CALLBACK (quit_cb), window);

  gtk_widget_set_visible (GTK_WIDGET (window), TRUE);

  /* We do not need the builder any more */
  g_object_unref (builder);
}

int
main (int   argc,
      char *argv[])
{
#ifdef GTK_SRCDIR
  g_chdir (GTK_SRCDIR);
#endif

  GtkApplication *app = gtk_application_new ("org.gtk.example", G_APPLICATION_DEFAULT_FLAGS);
  g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);

  int status = g_application_run (G_APPLICATION (app), argc, argv);
  g_object_unref (app);

  return status;
}

官方给的代码，没有说builder.ui这个文件放在哪里，我就放到了和main.c同级的子目录下，结果编译能通过，但是运行时报错。

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(main.exe:53272): Gtk-CRITICAL **: 23:14:02.343: gtk_window_set_application: assertion 'GTK_IS_WINDOW (window)' failed

(main.exe:53272): GLib-GObject-CRITICAL **: 23:14:02.348: invalid (NULL) pointer instance

(main.exe:53272): GLib-GObject-CRITICAL **: 23:14:02.351: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed

(main.exe:53272): GLib-GObject-CRITICAL **: 23:14:02.356: invalid (NULL) pointer instance

(main.exe:53272): GLib-GObject-CRITICAL **: 23:14:02.360: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed

(main.exe:53272): GLib-GObject-CRITICAL **: 23:14:02.364: invalid (NULL) pointer instance

(main.exe:53272): GLib-GObject-CRITICAL **: 23:14:02.367: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed

(main.exe:53272): Gtk-CRITICAL **: 23:14:02.372: gtk_widget_set_visible: assertion 'GTK_IS_WIDGET (widget)' failed

由于刚开始学，也不太会调试，完全没有头绪。但是编译能通过，觉得代码应该是没问题的。就猜，可能是ui文件路径不对。就试着改了两下，最后试出来了，gtk_builder_add_from_file (builder, "builder.ui", NULL); 这句中的builder.ui应该写这个项目中的相对路径，或是绝对路径。我放到了项目目录的src文件夹下，用相对路径写法，应该写成gtk_builder_add_from_file (builder, "src/builder.ui", NULL);,再次make run，就不再报错了。

如果这个以后想换个位置也能运行，这个ui文件应该放到另外的一个目录下，到时再研究怎么发布exe吧。