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GtkTreeView 控件

最后修改于 2023 年 10 月 18 日

在本 GTK+ 编程教程中，我们将使用 GtkTreeView 控件。

GtkTreeView 控件是一个复杂的控件，可以用来显示列表和树。该控件可以有一个或多个列。GtkTreeView 控件具有 MVC（模型-视图-控制器）设计架构。这意味着数据与视图是分离的。

还有几个与其他 GtkTreeView 控件一起使用的对象。GtkCellRenderer 决定了数据如何在 GtkTreeViewColumn 中显示。GtkListStore 和 GtkTreeStore 代表模型。它们处理显示在 GtkTreeView 控件中的数据。GtkTreeIter 是一个用于引用 GtkTreeView 中的行的结构。GtkTreeSelection 是一个处理选择的对象。

列表视图

第一个例子将展示一个简单的列表视图。我们显示文本数据。

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 中显示五个项目。我们只有一列，并且隐藏了该列的标题。我们将一个 GtkVBox 放置在窗口中。该框有两个控件：一个 GtkTreeView 和一个 GtkLabel。

list = gtk_tree_view_new();

gtk_tree_view_new 函数创建一个新的 GtkTreeView 控件。

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);

GtkLabel 被创建并放置在 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，我们创建一个单列并将其附加到列表中。

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（一个模型）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，该模型将随视图自动销毁。

add_to_list(list, "Aliens");

此用户函数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 函数调用获取模型。我们追加一个新行，并为该行设置一个值，该行由 GtkTreeIter 对象引用。

selection = gtk_tree_view_get_selection(GTK_TREE_VIEW(list));

不需要显式创建 GtkTreeSelection；它与 GtkTreeView 控件一起自动创建。使用 gtk_tree_view_get_selection 函数调用获取对该控件的引用。

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

GtkTreeSelection 的 changed 信号连接到 on_changed 处理程序。

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);

在处理程序函数内部，我们获取由 iter 对象引用的行中单元格的值。

gtk_label_set_text(GTK_LABEL(label), value);

检索到的值使用 gtk_label_set_text 函数设置为标签。

List view
图：列表视图

动态列表视图

第二个例子在前面的基础上增加了额外的功能。我们将能够从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;
}

在该示例中，我们有三个按钮和一个文本输入框。这些按钮用于添加新项目、删除选定项目和删除所有项目。

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，只有当列表中至少剩下一个项目时，我们才能删除项目。

Dynamic List view
图：动态列表视图

树视图

以下示例使用 GtkTreeView 控件来显示分层数据。在前面的两个示例中，我们使用了列表视图；现在我们将使用树视图。

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;
}

在该示例中，我们将编程语言分为两组：脚本语言和编译语言。语言类别用作其项目列表的顶级节点。当前选定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 函数创建一个 GtkTreeStore，它是一个与 GtkTreeView 一起使用的类似树的数据结构。

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中。

Tree View
图：树视图

在本章中，我们介绍了 GtkTreeView 控件。