`GtkTreeView`小部件 - 《ZetCode 中文系列教程》

ListView
动态列表视图
TreeView

原文： http://zetcode.com/gui/gtk2/gtktreeview/

在 GTK+ 编程教程的这一部分中，我们使用GtkTreeView小部件。

GtkTreeView小部件是一个复杂的小部件，可用于显示列表和树。小部件可以具有一列或多列。 GtkTreeView小部件具有 MVC（模型视图控制器）设计架构。这意味着数据与视图是分开的。

GtkTreeView小部件还可以使用其他几个对象。 GtkCellRenderer确定如何在GtkTreeViewColumn中显示数据。 GtkListStore和GtkTreeStore代表模型。它们处理在GtkTreeView小部件中显示的数据。 GtkTreeIter是用于引用GtkTreeView中的行的结构。 GtkTreeSelection是处理选择的对象。

`ListView`

第一个示例将显示一个简单的列表视图。我们将显示文本数据。

listview.c

#include <gtk/gtk.h>
enum {
  LIST_ITEM = 0,
  N_COLUMNS
};
void init_list(GtkWidget *list) {
  GtkCellRenderer *renderer;
  GtkTreeViewColumn *column;
  GtkListStore *store;
  renderer = gtk_cell_renderer_text_new ();
  column = gtk_tree_view_column_new_with_attributes("List Items",
          renderer, "text", LIST_ITEM, NULL);
  gtk_tree_view_append_column(GTK_TREE_VIEW(list), column);
  store = gtk_list_store_new(N_COLUMNS, G_TYPE_STRING);
  gtk_tree_view_set_model(GTK_TREE_VIEW(list), 
      GTK_TREE_MODEL(store));
  g_object_unref(store);
}
void add_to_list(GtkWidget *list, const gchar *str) {
  GtkListStore *store;
  GtkTreeIter iter;
  store = GTK_LIST_STORE(gtk_tree_view_get_model
      (GTK_TREE_VIEW(list)));
  gtk_list_store_append(store, &iter);
  gtk_list_store_set(store, &iter, LIST_ITEM, str, -1);
}
void on_changed(GtkWidget *widget, gpointer label) {
  GtkTreeIter iter;
  GtkTreeModel *model;
  gchar *value;
  if (gtk_tree_selection_get_selected(
      GTK_TREE_SELECTION(widget), &model, &iter)) {
    gtk_tree_model_get(model, &iter, LIST_ITEM, &value,  -1);
    gtk_label_set_text(GTK_LABEL(label), value);
    g_free(value);
  }
}
int main(int argc, char *argv[]) {
  GtkWidget *window;
  GtkWidget *list;
  GtkWidget *vbox;
  GtkWidget *label;
  GtkTreeSelection *selection; 
  gtk_init(&argc, &argv);
  window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
  list = gtk_tree_view_new();
  gtk_window_set_title(GTK_WINDOW(window), "List view");
  gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
  gtk_container_set_border_width(GTK_CONTAINER(window), 10);
  gtk_window_set_default_size(GTK_WINDOW(window), 270, 250);
  gtk_tree_view_set_headers_visible(GTK_TREE_VIEW(list), FALSE);
  vbox = gtk_vbox_new(FALSE, 0);
  gtk_box_pack_start(GTK_BOX(vbox), list, TRUE, TRUE, 5);
  label = gtk_label_new("");
  gtk_box_pack_start(GTK_BOX(vbox), label, FALSE, FALSE, 5);
  gtk_container_add(GTK_CONTAINER(window), vbox);
  init_list(list);
  add_to_list(list, "Aliens");
  add_to_list(list, "Leon");
  add_to_list(list, "The Verdict");
  add_to_list(list, "North Face");
  add_to_list(list, "Der Untergang");
  selection = gtk_tree_view_get_selection(GTK_TREE_VIEW(list));
  g_signal_connect(selection, "changed", 
      G_CALLBACK(on_changed), label);
  g_signal_connect(G_OBJECT (window), "destroy",
      G_CALLBACK(gtk_main_quit), NULL);
  gtk_widget_show_all(window);
  gtk_main();
  return 0;
}

在我们的代码示例中，我们在GtkTreeView中显示了五个项目。我们只有一列，并且该列的标题是隐藏的。我们将GtkVBox放入窗口。该框具有两个小部件：GtkTreeView和GtkLabel。

list = gtk_tree_view_new();

gtk_tree_view_new()函数创建一个新的GtkTreeView小部件。

gtk_tree_view_set_headers_visible(GTK_TREE_VIEW(list), FALSE);

我们使用gtk_tree_view_set_headers_visible()函数隐藏列标题。

label = gtk_label_new("");
gtk_box_pack_start(GTK_BOX(vbox), label, FALSE, FALSE, 5);

创建GtkLabel并将其放置在GtkTreeView下方。

init_list(list);

此函数初始化列表。

renderer = gtk_cell_renderer_text_new();
column = gtk_tree_view_column_new_with_attributes("List Items",
        renderer, "text", LIST_ITEM, NULL);
gtk_tree_view_append_column(GTK_TREE_VIEW(list), column);

在该函数内部，我们创建并附加一列。

store = gtk_list_store_new(N_COLUMNS, G_TYPE_STRING);
gtk_tree_view_set_model(GTK_TREE_VIEW(list), 
    GTK_TREE_MODEL(store));

我们创建一个GtkListStore（模型）并将其设置为列表。

g_object_unref(store);

TreeView增加了存储对象的引用。我们使用g_object_unref()函数将引用从 2 减少到 1。然后随视图自动销毁模型。

add_to_list(list, "Aliens");

该用户功能将一个选项添加到列表中。

store = GTK_LIST_STORE(gtk_tree_view_get_model
    (GTK_TREE_VIEW(list)));
gtk_list_store_append(store, &iter);
gtk_list_store_set(store, &iter, LIST_ITEM, str, -1);

在add_to_list()函数内部，我们使用gtk_tree_view_get_model()函数调用获得模型。我们附加一个新行，并为该行设置一个值，该值由GtkTreeIter对象引用。

selection = gtk_tree_view_get_selection(GTK_TREE_VIEW(list));

不需要显式创建GtkTreeSelection；它是使用GtkTreeView小部件自动创建的。使用gtk_tree_view_get_selection()函数调用可获得对窗口小部件的引用。

g_signal_connect(selection, "changed", 
    G_CALLBACK(on_changed), label);

GtkTreeSelection的changed信号连接到on_changed()处理器。

if (gtk_tree_selection_get_selected(
    GTK_TREE_SELECTION(widget), &model, &iter)) {

gtk_tree_selection_get_selected()函数将iter设置为当前选定的节点。

gtk_tree_model_get(model, &iter, LIST_ITEM, &value,  -1);

在处理函数中，我们获取iter对象引用的行中单元格的值。

gtk_label_set_text(GTK_LABEL(label), value);

检索到的值通过gtk_label_set_text()函数设置为标签。

`GtkTreeView`小部件 - 图1

图：列表视图

动态列表视图

第二个示例在前一个示例中添加了其他功能。我们将能够在列表视图中添加和删除项目。

dynamiclistview.c

#include <gtk/gtk.h>
enum {
  LIST_ITEM = 0,
  N_COLUMNS
};
GtkWidget *list;
void append_item(GtkWidget *widget, gpointer entry) {
  GtkListStore *store;
  GtkTreeIter iter;
  const gchar *str = gtk_entry_get_text(entry); 
  store = GTK_LIST_STORE(gtk_tree_view_get_model(GTK_TREE_VIEW(list)));
  gtk_list_store_append(store, &iter);
  gtk_list_store_set(store, &iter, LIST_ITEM, str, -1);
  gtk_entry_set_text(entry, "");
}
void remove_item(GtkWidget *widget, gpointer selection) {
  GtkListStore *store;
  GtkTreeModel *model;
  GtkTreeIter  iter;
  store = GTK_LIST_STORE(gtk_tree_view_get_model(GTK_TREE_VIEW(list)));
  model = gtk_tree_view_get_model(GTK_TREE_VIEW(list));
  if (gtk_tree_model_get_iter_first(model, &iter) == FALSE) {
      return;
  }
  if (gtk_tree_selection_get_selected(GTK_TREE_SELECTION(selection), 
         &model, &iter)) {
    gtk_list_store_remove(store, &iter);
  }
}
void remove_all(GtkWidget *widget, gpointer selection) {
  GtkListStore *store;
  GtkTreeModel *model;
  GtkTreeIter  iter;
  store = GTK_LIST_STORE(gtk_tree_view_get_model(GTK_TREE_VIEW(list)));
  model = gtk_tree_view_get_model(GTK_TREE_VIEW(list));
  if (gtk_tree_model_get_iter_first(model, &iter) == FALSE) {
      return;
  }
  gtk_list_store_clear(store);
}
void init_list(GtkWidget *list) {
  GtkCellRenderer    *renderer;
  GtkTreeViewColumn  *column;
  GtkListStore       *store;
  renderer = gtk_cell_renderer_text_new();
  column = gtk_tree_view_column_new_with_attributes("List Item",
          renderer, "text", LIST_ITEM, NULL);
  gtk_tree_view_append_column(GTK_TREE_VIEW(list), column);
  store = gtk_list_store_new(N_COLUMNS, G_TYPE_STRING);
  gtk_tree_view_set_model(GTK_TREE_VIEW(list), GTK_TREE_MODEL(store));
  g_object_unref(store);
}
int main(int argc, char *argv[]) {
  GtkWidget *window;
  GtkWidget *sw;
  GtkWidget *remove;
  GtkWidget *add;
  GtkWidget *removeAll;
  GtkWidget *entry;
  GtkWidget *vbox;
  GtkWidget *hbox;
  GtkTreeSelection *selection; 
  gtk_init(&argc, &argv);
  window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
  gtk_window_set_title(GTK_WINDOW(window), "List view");
  gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
  gtk_container_set_border_width(GTK_CONTAINER (window), 10);
  gtk_widget_set_size_request(window, 370, 270);
  sw = gtk_scrolled_window_new(NULL, NULL);
  list = gtk_tree_view_new();  
  gtk_container_add(GTK_CONTAINER(sw), list);
  gtk_scrolled_window_set_policy(GTK_SCROLLED_WINDOW(sw),
            GTK_POLICY_AUTOMATIC, GTK_POLICY_AUTOMATIC);
  gtk_scrolled_window_set_shadow_type(GTK_SCROLLED_WINDOW(sw),
            GTK_SHADOW_ETCHED_IN);
  gtk_tree_view_set_headers_visible(GTK_TREE_VIEW(list), FALSE);
  vbox = gtk_vbox_new(FALSE, 0);
  gtk_box_pack_start(GTK_BOX(vbox), sw, TRUE, TRUE, 5);
  hbox = gtk_hbox_new(FALSE, 5);
  add = gtk_button_new_with_label("Add");
  remove = gtk_button_new_with_label("Remove");
  removeAll = gtk_button_new_with_label("Remove All");
  entry = gtk_entry_new();
  gtk_widget_set_size_request(entry, 120, -1);
  gtk_box_pack_start(GTK_BOX(hbox), add, FALSE, TRUE, 3);
  gtk_box_pack_start(GTK_BOX(hbox), entry, FALSE, TRUE, 3);
  gtk_box_pack_start(GTK_BOX(hbox), remove, FALSE, TRUE, 3);
  gtk_box_pack_start(GTK_BOX(hbox), removeAll, FALSE, TRUE, 3);
  gtk_box_pack_start(GTK_BOX(vbox), hbox, FALSE, TRUE, 3);
  gtk_container_add(GTK_CONTAINER(window), vbox);
  init_list(list);
  selection = gtk_tree_view_get_selection(GTK_TREE_VIEW(list));
  g_signal_connect(G_OBJECT(add), "clicked",
          G_CALLBACK(append_item), entry);
  g_signal_connect(G_OBJECT(remove), "clicked",
          G_CALLBACK(remove_item), selection);
  g_signal_connect(G_OBJECT(removeAll), "clicked",
          G_CALLBACK(remove_all), selection);
  g_signal_connect(G_OBJECT(window), "destroy",
          G_CALLBACK(gtk_main_quit), NULL);
  gtk_widget_show_all(window);
  gtk_main();
  return 0;
}

在示例中，我们有三个按钮和一个文本输入。这些按钮添加一个新项目，删除选定的项目，然后删除所有项目。

sw = gtk_scrolled_window_new(NULL, NULL);
list = gtk_tree_view_new();  
gtk_container_add(GTK_CONTAINER(sw), list);

GtkTreeView放置在滚动窗口内。

if (gtk_tree_selection_get_selected(GTK_TREE_SELECTION(selection), 
    &model, &iter)) {
  gtk_list_store_remove(store, &iter);
}

gtk_list_store_remove()函数从列表中删除一个项目。

gtk_list_store_clear(store);

gtk_list_store_clear()从列表中删除所有项目。

if (gtk_tree_model_get_iter_first(model, &iter) == FALSE) {
    return;
}

此代码检查列表中是否还有剩余项目。显然，只有列表中至少剩余一个，我们才能删除项目。

`GtkTreeView`小部件 - 图2

图：动态列表视图

`TreeView`

以下示例使用GtkTreeView小部件显示分层数据。在前两个示例中，我们使用了列表视图。现在我们将使用树形视图。

treeview.c

#include <gtk/gtk.h>
enum {
  COLUMN = 0,
  NUM_COLS
};
void on_changed(GtkWidget *widget, gpointer statusbar) {
  GtkTreeIter iter;
  GtkTreeModel *model;
  gchar *value;
  if (gtk_tree_selection_get_selected(
      GTK_TREE_SELECTION(widget), &model, &iter)) {
    gtk_tree_model_get(model, &iter, COLUMN, &value,  -1);
    gtk_statusbar_push(GTK_STATUSBAR(statusbar),
        gtk_statusbar_get_context_id(GTK_STATUSBAR(statusbar), 
            value), value);
    g_free(value);
  }
}
GtkTreeModel *create_and_fill_model(void) {
  GtkTreeStore *treestore;
  GtkTreeIter toplevel, child;
  treestore = gtk_tree_store_new(NUM_COLS,
                  G_TYPE_STRING);
  gtk_tree_store_append(treestore, &toplevel, NULL);
  gtk_tree_store_set(treestore, &toplevel,
                     COLUMN, "Scripting languages",
                     -1);
  gtk_tree_store_append(treestore, &child, &toplevel);
  gtk_tree_store_set(treestore, &child,
                     COLUMN, "Python",
                     -1);
  gtk_tree_store_append(treestore, &child, &toplevel);
  gtk_tree_store_set(treestore, &child,
                     COLUMN, "Perl",
                     -1);
  gtk_tree_store_append(treestore, &child, &toplevel);
  gtk_tree_store_set(treestore, &child,
                     COLUMN, "PHP",
                     -1);
  gtk_tree_store_append(treestore, &toplevel, NULL);
  gtk_tree_store_set(treestore, &toplevel,
                     COLUMN, "Compiled languages",
                     -1);
  gtk_tree_store_append(treestore, &child, &toplevel);
  gtk_tree_store_set(treestore, &child,
                     COLUMN, "C",
                     -1);
  gtk_tree_store_append(treestore, &child, &toplevel);
  gtk_tree_store_set(treestore, &child,
                     COLUMN, "C++",
                     -1);
  gtk_tree_store_append(treestore, &child, &toplevel);
  gtk_tree_store_set(treestore, &child,
                     COLUMN, "Java",
                     -1);
  return GTK_TREE_MODEL(treestore);
}
GtkWidget *create_view_and_model(void) {
  GtkTreeViewColumn *col;
  GtkCellRenderer *renderer;
  GtkWidget *view;
  GtkTreeModel *model;
  view = gtk_tree_view_new();
  col = gtk_tree_view_column_new();
  gtk_tree_view_column_set_title(col, "Programming languages");
  gtk_tree_view_append_column(GTK_TREE_VIEW(view), col);
  renderer = gtk_cell_renderer_text_new();
  gtk_tree_view_column_pack_start(col, renderer, TRUE);
  gtk_tree_view_column_add_attribute(col, renderer, 
      "text", COLUMN);
  model = create_and_fill_model();
  gtk_tree_view_set_model(GTK_TREE_VIEW(view), model);
  g_object_unref(model); 
  return view;
}
int main(int argc, char *argv[]) {
  GtkWidget *window;
  GtkWidget *view;
  GtkTreeSelection *selection; 
  GtkWidget *vbox;
  GtkWidget *statusbar;
  gtk_init(&argc, &argv);
  window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
  gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER);
  gtk_window_set_title(GTK_WINDOW(window), "Tree view");
  gtk_widget_set_size_request(window, 350, 300);
  vbox = gtk_vbox_new(FALSE, 2);
  gtk_container_add(GTK_CONTAINER(window), vbox);
  view = create_view_and_model();
  selection = gtk_tree_view_get_selection(GTK_TREE_VIEW(view));
  gtk_box_pack_start(GTK_BOX(vbox), view, TRUE, TRUE, 1);
  statusbar = gtk_statusbar_new();
  gtk_box_pack_start(GTK_BOX(vbox), statusbar, FALSE, TRUE, 1);
  g_signal_connect(selection, "changed", 
      G_CALLBACK(on_changed), statusbar);
  g_signal_connect (G_OBJECT (window), "destroy",
          G_CALLBACK(gtk_main_quit), NULL);
  gtk_widget_show_all(window);
  gtk_main();
  return 0;
}

在示例中，我们将编程语言分为两组：脚本语言和编译语言。语言类别是其项目列表的顶级节点。当前选择的项目显示在状态栏中。创建树视图的步骤与创建列表视图非常相似。

treestore = gtk_tree_store_new(NUM_COLS,
                G_TYPE_STRING);

gtk_tree_store_new()函数创建GtkTreeStore，它是与GtkTreeView一起使用的树状数据结构。

gtk_tree_store_append(treestore, &toplevel, NULL);
gtk_tree_store_set(treestore, &toplevel,
                  COLUMN, "Scripting languages",
                  -1);

这两行创建一个顶级节点。

gtk_tree_store_append(treestore, &child, &toplevel);
gtk_tree_store_set(treestore, &child,
                  COLUMN, "Python",
                  -1);

在这里，我们将一个子项添加到顶级节点。

`GtkTreeView`小部件 - 图3

图：树形视图

在本章中，我们介绍了GtkTreeView小部件。