Gtk4 C File tree view

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Summary

The problem lies in creating a file tree view in Gtk4 using C, where the classic arrow to expand folders is missing, and double-clicking does not open them. The provided code attempts to create a tree model using GtkTreeListModel and GtkDirectoryList, but it does not correctly implement the expansion functionality.

Root Cause

The root cause of the issue is the incorrect usage of GtkTreeExpander and the lack of implementation of the expansion logic. The create_tree_model function returns a GListModel for directories, but it does not handle the expansion of the tree view.

Why This Happens in Real Systems

This issue occurs in real systems because of the following reasons:

  • Incorrect usage of GtkTreeExpander and GtkTreeListModel
  • Lack of implementation of the expansion logic
  • Insufficient handling of directory and file types in the tree model
  • Inadequate binding of data to the tree view

Real-World Impact

The impact of this issue is:

  • Users cannot navigate through the file system using the tree view
  • The application does not provide a user-friendly interface for file browsing
  • The lack of expansion functionality makes it difficult to access files and directories

Example or Code

// Correct implementation of create_tree_model
static GListModel * create_tree_model(gpointer item, gpointer user_data) {
    GtkTreeListRow *row = GTK_TREE_LIST_ROW(item);
    GFileInfo *info = G_FILE_INFO(gtk_tree_list_row_get_item(row));
    if (g_file_info_get_file_type(info) == G_FILE_TYPE_DIRECTORY) {
        GFile *file = G_FILE(g_file_info_get_attribute_object(info, "standard::file"));
        if (file) {
            GtkDirectoryList *dir = gtk_directory_list_new("standard::name,standard::display-name,standard::icon,standard::file", file);
            return G_LIST_MODEL(dir);
        }
    }
    return NULL;
}

// Correct implementation of setup_cb and bind_cb
static void setup_cb(GtkSignalListItemFactory *factory, GtkListItem *list_item) {
    GtkWidget *expander = gtk_tree_expander_new();
    GtkWidget *box = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 8);
    GtkWidget *image = gtk_image_new();
    GtkWidget *label = gtk_label_new(NULL);
    gtk_box_append(GTK_BOX(box), image);
    gtk_box_append(GTK_BOX(box), label);
    gtk_tree_expander_set_child(GTK_TREE_EXPANDER(expander), box);
    gtk_list_item_set_child(list_item, expander);
}

static void bind_cb(GtkSignalListItemFactory *factory, GtkListItem *list_item) {
    GtkTreeListRow *row = GTK_TREE_LIST_ROW(gtk_list_item_get_item(list_item));
    GFileInfo *info = G_FILE_INFO(gtk_tree_list_row_get_item(row));
    GtkWidget *expander = gtk_list_item_get_child(list_item);
    GtkWidget *box = gtk_tree_expander_get_child(GTK_TREE_EXPANDER(expander));
    GtkWidget *image = gtk_widget_get_first_child(box);
    GtkWidget *label = gtk_widget_get_next_sibling(image);
    gtk_tree_expander_set_list_row(GTK_TREE_EXPANDER(expander), row);
    if (info) {
        gtk_label_set_text(GTK_LABEL(label), g_file_info_get_display_name(info));
        gtk_image_set_from_gicon(GTK_IMAGE(image), g_file_info_get_icon(info));
    }
}

How Senior Engineers Fix It

Senior engineers fix this issue by:

  • Correctly implementing the create_tree_model function to handle directory and file types
  • Using GtkTreeExpander and GtkTreeListModel correctly to provide expansion functionality
  • Binding data to the tree view using setup_cb and bind_cb functions
  • Handling user interactions, such as double-clicking, to open files and directories

Why Juniors Miss It

Juniors may miss this issue due to:

  • Lack of experience with Gtk4 and C
  • Insufficient understanding of GtkTreeExpander and GtkTreeListModel
  • Inadequate knowledge of tree view implementation and expansion logic
  • Failure to test the application thoroughly to identify the issue