如何在使用 GTK 4 Columnview 列表模型时添加多列排序功能时遇到问题。 C 编码，Linux/GNOME 环境

Question

我正在测试 GTK4 列视图列表模型以显示多列。用 C 编码。我已经使该代码可以工作（请参阅下面的代码）。我在添加标准列视图排序功能时遇到了麻烦，使用 GTK 4.0 文档中引用的 C 代码片段作为指导

C 代码片段如下所示：https://docs.gtk.org/gtk4/method.ColumnView.get_sorter.html

工作代码，预排序尝试，如下。应用程序显示列，标准输出没有错误，按预期工作。

// Use for testing columnview

#include <gtk/gtk.h>

// Setup custom type - each item has two strings which will be displayed in two columns

#define TESTCOL_TYPE_ITEM (testcol_item_get_type())
G_DECLARE_FINAL_TYPE (TestColItem, testcol_item, TESTCOL, ITEM, GObject)

struct _TestColItem
{
    GObject parent_instance;
    const char *str1;
    const char *str2;
};

struct _TestColItemClass
{
    GObjectClass parent_class;
};

G_DEFINE_TYPE (TestColItem, testcol_item, G_TYPE_OBJECT)

static void testcol_item_init(TestColItem *item)
{
}

static void testcol_item_class_init(TestColItemClass *class)
{
}
enter image description here
// Set label for factory widget
static void setup_cb(GtkSignalListItemFactory *factory,GObject  *listitem)
{
    GtkWidget *label =gtk_label_new(NULL);
    gtk_list_item_set_child(GTK_LIST_ITEM(listitem),label);
}

// Set text from the column1 passed item for label
static void bind_col1_cb(GtkSignalListItemFactory *factory, GtkListItem *listitem)
{
    GtkWidget *label = gtk_list_item_get_child(listitem);
    TestColItem *item = gtk_list_item_get_item(GTK_LIST_ITEM(listitem));
    const char *string = item->str1;
    g_print("value is %s\n",string); // Show on std out
    gtk_label_set_text(GTK_LABEL (label), string);
}
// Set text from the column2 passed item for label
static void bind_col2_cb(GtkSignalListItemFactory *factory, GtkListItem *listitem)
{
    GtkWidget *label = gtk_list_item_get_child(listitem);
    TestColItem *item = gtk_list_item_get_item(GTK_LIST_ITEM(listitem));
    const char *string = item->str2;
    g_print("value is %s\n",string); // Show on std out
    gtk_label_set_text(GTK_LABEL (label), string);
}

// Create the custom object
static TestColItem * testcol_item_new(const char *str1, const char *str2)
{
    TestColItem  *item = g_object_new(TESTCOL_TYPE_ITEM, NULL);
    item->str1 = g_strdup(str1);
    item->str2 = g_strdup(str2);
    return item;
}   

// Activate
static void activate (GtkApplication* app, gpointer user_data)
{
    // Create and populate custom list model
    GListStore *store = g_list_store_new(G_TYPE_OBJECT); 
    GListModel *model = G_LIST_MODEL(store);

    g_list_store_append(store,testcol_item_new("abc1","ghi1"));
    g_list_store_append(store,testcol_item_new("def2","aaa2"));
    g_list_store_append(store,testcol_item_new("aaa3","jkl3"));

    // Set selection for custom model
    GtkSingleSelection *selection = gtk_single_selection_new(G_LIST_MODEL(model));
    gtk_single_selection_set_autoselect(selection,TRUE);

    // Set Windows in child scrolled window
    GtkWidget *window = gtk_application_window_new (app);
    gtk_window_set_title (GTK_WINDOW (window), "Test");
    gtk_window_set_default_size (GTK_WINDOW (window), 200, 200);
    GtkWidget *scrolled_window = gtk_scrolled_window_new (); 
    gtk_window_set_child (GTK_WINDOW(window), scrolled_window);

    // Add column view.  Put in scrolled window.  
    GtkWidget *cv = gtk_column_view_new(GTK_SELECTION_MODEL (selection));
    gtk_scrolled_window_set_child(GTK_SCROLLED_WINDOW(scrolled_window),cv);
    gtk_column_view_set_show_column_separators (GTK_COLUMN_VIEW (cv),TRUE);

    // Factory setup and bind for column view
    GtkListItemFactory *factory = gtk_signal_list_item_factory_new();
    g_signal_connect(factory, "setup", G_CALLBACK(setup_cb),NULL);
    g_signal_connect(factory, "bind", G_CALLBACK(bind_col1_cb),NULL);
    GtkColumnViewColumn *column = gtk_column_view_column_new("Col1", factory);
    gtk_column_view_append_column (GTK_COLUMN_VIEW (cv), column);

    // Factory setup and bind for column view
    factory = gtk_signal_list_item_factory_new();
    g_signal_connect(factory, "setup", G_CALLBACK(setup_cb),NULL);
    g_signal_connect(factory, "bind", G_CALLBACK(bind_col2_cb),NULL);
    column = gtk_column_view_column_new("Col2", factory);
    gtk_column_view_append_column (GTK_COLUMN_VIEW (cv), column);


    // Show window
    gtk_window_present (GTK_WINDOW (window));
}

// Init application
int main (int argc, char **argv)
{
    GtkApplication *app;
    int status;

    app = gtk_application_new ("org.gtk.example", G_APPLICATION_DEFAULT_FLAGS);
    g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
    status = g_application_run (G_APPLICATION (app), argc, argv);
    g_object_unref (app);

    return status;
}

问题

我尝试使用上面的 C 代码片段作为指导来添加排序功能。工作时，我们会在列标题中看到一个排序图标，单击该图标会激活排序。许多代码测试变体，这是一个：

首先我注释掉了 gtk_column_view_append_column 然后添加：

    // First comment out append and then add
    GtkSorter *sorter = gtk_column_view_get_sorter ((GtkColumnView *) cv); // get the sorter for col
    gtk_column_view_column_set_sorter(column, sorter); // set the sorter on column
    gtk_column_view_append_column (GTK_COLUMN_VIEW (cv), column); // put col into colview
    GtkSortListModel *smodel = gtk_sort_list_model_new ((GListModel *) model, sorter);
    selection = gtk_single_selection_new(G_LIST_MODEL(smodel));
    gtk_column_view_set_model ((GtkColumnView *)cv, (GtkSelectionModel *)selection);

标准输出已显示。

（输出：22870）：GLib-GIO-CRITICAL **：21：39：59.759：g_list_model_get_n_items：断言“G_IS_LIST_MODEL（列表）”失败

（输出：22870）：GLib-GIO-CRITICAL **：21：39：59.759：g_list_model_get_n_items：断言“G_IS_LIST_MODEL（列表）”失败

（输出：22870）：GLib-GIO-CRITICAL **：21：39：59.759：g_list_model_get_n_items：断言“G_IS_LIST_MODEL（列表）”失败

（输出：22870）：GLib-GIO-CRITICAL **：21：39：59.759：g_list_model_get_n_items：断言“G_IS_LIST_MODEL（列表）”失败

（输出：22870）：GLib-GIO-CRITICAL **：21：39：59.759：g_list_model_get_n_items：断言“G_IS_LIST_MODEL（列表）”失败

（输出：22870）：GLib-GIO-CRITICAL **：21：39：59.759：g_list_model_get_n_items：断言“G_IS_LIST_MODEL（列表）”失败

（输出：22870）：GLib-GIO-CRITICAL **：21：39：59.797：g_list_model_get_n_items：断言“G_IS_LIST_MODEL（列表）”失败

（出：22870）：GLib-GIO-CRITICAL **：21：39：59.807：g_list_model_get_n_items：断言“G_IS_LIST_MODEL（列表）”失败

显然我不明白这一点。继续实验，但如果有任何关于如何将 C 代码添加到我的工作示例中的建议，该示例将在两列上引入排序功能，我将不胜感激。

Answer 1

在 discourse.gnome.org 上得到了有用的建议。必须手动添加排序器（虽然排序在某种意义上是columnview内置的，但必须手动添加排序器）。另外，您可以使用 null 定义列视图，以允许您创建与排序器关联的列，这有助于将排序放在列视图模型下。

修改后的代码在这里。仍然没有排序，但这看起来像是评估属性的表达式有问题，基本排序函数代码就在那里

// Use for testing columnview

#include <gtk/gtk.h>

// Setup custom type - each item has two strings which will be displayed in two columns

#define TESTCOL_TYPE_ITEM (testcol_item_get_type())
G_DECLARE_FINAL_TYPE (TestColItem, testcol_item, TESTCOL, ITEM, GObject)

struct _TestColItem
{
    GObject parent_instance;
    const char *str1;
    const char *str2;
};

struct _TestColItemClass
{
    GObjectClass parent_class;
};

G_DEFINE_TYPE (TestColItem, testcol_item, G_TYPE_OBJECT)

static void testcol_item_init(TestColItem *item)
{
}

static void testcol_item_class_init(TestColItemClass *class)
{
}

// Set label for factory widget
static void setup_cb(GtkSignalListItemFactory *factory,GObject  *listitem)
{
    GtkWidget *label =gtk_label_new(NULL);
    gtk_list_item_set_child(GTK_LIST_ITEM(listitem),label);
}

// Set text from the column1 passed item for label
static void bind_col1_cb(GtkSignalListItemFactory *factory, GtkListItem *listitem)
{
    GtkWidget *label = gtk_list_item_get_child(listitem);
    TestColItem *item = gtk_list_item_get_item(GTK_LIST_ITEM(listitem));
    const char *string = item->str1;
    g_print("value is %s\n",string); // Show on std out
    gtk_label_set_text(GTK_LABEL (label), string);
}
// Set text from the column2 passed item for label
static void bind_col2_cb(GtkSignalListItemFactory *factory, GtkListItem *listitem)
{
    GtkWidget *label = gtk_list_item_get_child(listitem);
    TestColItem *item = gtk_list_item_get_item(GTK_LIST_ITEM(listitem));
    const char *string = item->str2;
    g_print("value is %s\n",string); // Show on std out
    gtk_label_set_text(GTK_LABEL (label), string);
}

// Create the custom object
static TestColItem * testcol_item_new(const char *str1, const char *str2)
{
    TestColItem  *item = g_object_new(TESTCOL_TYPE_ITEM, NULL);
    item->str1 = g_strdup(str1);
    item->str2 = g_strdup(str2);
    return item;
}   

// Activate
static void activate (GtkApplication* app, gpointer user_data)
{
    // Create and populate custom list model
    GListStore *store = g_list_store_new(G_TYPE_OBJECT); 
    g_list_store_append(store,testcol_item_new("abc1","ghi1"));
    g_list_store_append(store,testcol_item_new("def2","aaa2"));
    g_list_store_append(store,testcol_item_new("aaa3","jkl3"));

    // Set Windows in child scrolled window
    GtkWidget *window = gtk_application_window_new (app);
    gtk_window_set_title (GTK_WINDOW (window), "Test");
    gtk_window_set_default_size (GTK_WINDOW (window), 200, 200);
    GtkWidget *scrolled_window = gtk_scrolled_window_new (); 
    gtk_window_set_child (GTK_WINDOW(window), scrolled_window);

    // Add column view.  Put in scrolled window.  
    GtkWidget *cv = gtk_column_view_new(NULL); // Null for now want to add sorter
    gtk_scrolled_window_set_child(GTK_SCROLLED_WINDOW(scrolled_window),cv);
    gtk_column_view_set_show_column_separators (GTK_COLUMN_VIEW (cv),TRUE);

    // Factory setup and bind for column 1 
    GtkListItemFactory *factory = gtk_signal_list_item_factory_new();
    g_signal_connect(factory, "setup", G_CALLBACK(setup_cb),NULL);
    g_signal_connect(factory, "bind", G_CALLBACK(bind_col1_cb),NULL);
    GtkColumnViewColumn *column = gtk_column_view_column_new("Col1", factory);
    GtkSorter *sorter = GTK_SORTER (gtk_string_sorter_new (gtk_property_expression_new (TESTCOL_TYPE_ITEM, NULL, "str1")));
    gtk_column_view_column_set_sorter (column, GTK_SORTER (sorter));
    gtk_column_view_append_column (GTK_COLUMN_VIEW (cv), column);

    // Factory setup and bind for column 2
    factory = gtk_signal_list_item_factory_new();
    g_signal_connect(factory, "setup", G_CALLBACK(setup_cb),NULL);
    g_signal_connect(factory, "bind", G_CALLBACK(bind_col2_cb),NULL);
    column = gtk_column_view_column_new("Col2", factory);
    sorter = GTK_SORTER (gtk_string_sorter_new (gtk_property_expression_new (TESTCOL_TYPE_ITEM, NULL, "str2")));
    gtk_column_view_column_set_sorter (column, GTK_SORTER (sorter));
    gtk_column_view_append_column (GTK_COLUMN_VIEW (cv), column);

    // Setup sort model then overlay with with columnview
    sorter = g_object_ref (gtk_column_view_get_sorter (GTK_COLUMN_VIEW (cv)));
    GtkSortListModel *model = gtk_sort_list_model_new (G_LIST_MODEL (store), sorter);
    GtkSingleSelection *selection = gtk_single_selection_new (G_LIST_MODEL (model));
    gtk_single_selection_set_autoselect (selection, TRUE);
    gtk_column_view_set_model (GTK_COLUMN_VIEW (cv), GTK_SELECTION_MODEL (selection));

    // Show window
    gtk_window_present (GTK_WINDOW (window));
}

// Init application
int main (int argc, char **argv)
{
    GtkApplication *app;
    int status;

    app = gtk_application_new ("org.gtk.example", G_APPLICATION_DEFAULT_FLAGS);
    g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);
    status = g_application_run (G_APPLICATION (app), argc, argv);
    g_object_unref (app);

    return status;
}