GTK 对话框 - 《ZetCode 中文系列教程》

MessageDialog
GtkAboutDialog
GtkFontSelectionDialog
GtkColorSelectionDialog

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

在 GTK+ 编程教程的这一部分中，我们使用对话框。

对话框窗口或对话框是大多数现代 GUI 应用必不可少的部分。对话被定义为两个或更多人之间的对话。在计算机应用中，对话框是一个窗口，用于与应用“对话”。对话框用于输入数据，修改数据，更改应用设置等。

`MessageDialog`

消息对话框是方便的对话框，可向应用的用户提供消息。该消息包含文本和图像数据。

messagedialogs.c

#include <gtk/gtk.h>
void show_info(GtkWidget *widget, gpointer window) {
  GtkWidget *dialog;
  dialog = gtk_message_dialog_new(GTK_WINDOW(window),
            GTK_DIALOG_DESTROY_WITH_PARENT,
            GTK_MESSAGE_INFO,
            GTK_BUTTONS_OK,
            "Download Completed");
  gtk_window_set_title(GTK_WINDOW(dialog), "Information");
  gtk_dialog_run(GTK_DIALOG(dialog));
  gtk_widget_destroy(dialog);
}
void show_error(GtkWidget *widget, gpointer window) {
  GtkWidget *dialog;
  dialog = gtk_message_dialog_new(GTK_WINDOW(window),
            GTK_DIALOG_DESTROY_WITH_PARENT,
            GTK_MESSAGE_ERROR,
            GTK_BUTTONS_OK,
            "Error loading file");
  gtk_window_set_title(GTK_WINDOW(dialog), "Error");
  gtk_dialog_run(GTK_DIALOG(dialog));
  gtk_widget_destroy(dialog);
}
void show_question(GtkWidget *widget, gpointer window) {
  GtkWidget *dialog;
  dialog = gtk_message_dialog_new(GTK_WINDOW(window),
            GTK_DIALOG_DESTROY_WITH_PARENT,
            GTK_MESSAGE_QUESTION,
            GTK_BUTTONS_YES_NO,
            "Are you sure to quit?");
  gtk_window_set_title(GTK_WINDOW(dialog), "Question");
  gtk_dialog_run(GTK_DIALOG(dialog));
  gtk_widget_destroy(dialog);
}
void show_warning(GtkWidget *widget, gpointer window) {
  GtkWidget *dialog;
  dialog = gtk_message_dialog_new(GTK_WINDOW(window),
            GTK_DIALOG_DESTROY_WITH_PARENT,
            GTK_MESSAGE_WARNING,
            GTK_BUTTONS_OK,
            "Unallowed operation");
  gtk_window_set_title(GTK_WINDOW(dialog), "Warning");
  gtk_dialog_run(GTK_DIALOG(dialog));
  gtk_widget_destroy(dialog);
}
int main(int argc, char *argv[]) {
  GtkWidget *window;
  GtkWidget *table;
  GtkWidget *info;
  GtkWidget *warn;
  GtkWidget *que;
  GtkWidget *err;
  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_default_size(GTK_WINDOW(window), 220, 150);
  gtk_window_set_title(GTK_WINDOW(window), "Message dialogs");
  table = gtk_table_new(2, 2, TRUE);
  gtk_table_set_row_spacings(GTK_TABLE(table), 2);
  gtk_table_set_col_spacings(GTK_TABLE(table), 2);
  info = gtk_button_new_with_label("Info");
  warn = gtk_button_new_with_label("Warning");
  que = gtk_button_new_with_label("Question");
  err = gtk_button_new_with_label("Error");
  gtk_table_attach(GTK_TABLE(table), info, 0, 1, 0, 1, 
      GTK_FILL, GTK_FILL, 3, 3);
  gtk_table_attach(GTK_TABLE(table), warn, 1, 2, 0, 1, 
      GTK_FILL, GTK_FILL, 3, 3);
  gtk_table_attach(GTK_TABLE(table), que, 0, 1, 1, 2, 
      GTK_FILL, GTK_FILL, 3, 3);
  gtk_table_attach(GTK_TABLE(table), err, 1, 2, 1, 2, 
      GTK_FILL, GTK_FILL, 3, 3);
  gtk_container_add(GTK_CONTAINER(window), table);
  gtk_container_set_border_width(GTK_CONTAINER(window), 15);
  g_signal_connect(G_OBJECT(info), "clicked", 
        G_CALLBACK(show_info), (gpointer) window); 
  g_signal_connect(G_OBJECT(warn), "clicked", 
        G_CALLBACK(show_warning), (gpointer) window); 
  g_signal_connect(G_OBJECT(que), "clicked", 
        G_CALLBACK(show_question), (gpointer) window); 
  g_signal_connect(G_OBJECT(err), "clicked", 
        G_CALLBACK(show_error), (gpointer) window); 
  g_signal_connect(G_OBJECT(window), "destroy",
        G_CALLBACK(gtk_main_quit), G_OBJECT(window));
  gtk_widget_show_all(window);
  gtk_main();
  return 0;
}

在我们的示例中，我们显示了四种消息对话框：信息，警告，问题和错误消息对话框。

void show_question(GtkWidget *widget, gpointer window) {
  GtkWidget *dialog;
  dialog = gtk_message_dialog_new(GTK_WINDOW(window),
            GTK_DIALOG_DESTROY_WITH_PARENT,
            GTK_MESSAGE_QUESTION,
            GTK_BUTTONS_YES_NO,
            "Are you sure to quit?");
  gtk_window_set_title(GTK_WINDOW(dialog), "Question");
  gtk_dialog_run(GTK_DIALOG(dialog));
  gtk_widget_destroy(dialog);
}

在show_question()函数中，我们弹出消息对话框。消息对话框是使用gtk_message_dialog_new()调用创建的。函数的参数指定我们创建哪种消息对话框。 GTK_MESSAGE_QUESTION常量创建一个问题类型对话框。 GTK_BUTTONS_YES_NO常量将在对话框中添加“是”和“否”按钮。最后一个参数是我们在对话框中显示的文本。 gtk_dialog_run()函数显示对话框并阻塞主循环，直到对话框响应或被破坏为止。该对话框必须使用gtk_widget_destroy()函数销毁。

GTK 对话框 - 图1

GTK 对话框 - 图2

GTK 对话框 - 图3

GTK 对话框 - 图4

图：消息对话框

`GtkAboutDialog`

GtkAboutDialog是一个对话框，其目的是显示有关应用的信息。它可以显示徽标，应用名称，版本，版权，网站和许可证信息。也有可能对作者，文档撰写者，翻译者和艺术家予以赞扬。

aboutdialog.c

#include <gtk/gtk.h>
void show_about(GtkWidget *widget, gpointer data) {
  GdkPixbuf *pixbuf = gdk_pixbuf_new_from_file("battery.png", NULL);
  GtkWidget *dialog = gtk_about_dialog_new();
  gtk_about_dialog_set_name(GTK_ABOUT_DIALOG(dialog), "Battery");
  gtk_about_dialog_set_version(GTK_ABOUT_DIALOG(dialog), "0.9"); 
  gtk_about_dialog_set_copyright(GTK_ABOUT_DIALOG(dialog),"(c) Jan Bodnar");
  gtk_about_dialog_set_comments(GTK_ABOUT_DIALOG(dialog), 
     "Battery is a simple tool for battery checking.");
  gtk_about_dialog_set_website(GTK_ABOUT_DIALOG(dialog), 
     "http://www.batteryhq.net");
  gtk_about_dialog_set_logo(GTK_ABOUT_DIALOG(dialog), pixbuf);
  g_object_unref(pixbuf), pixbuf = NULL;
  gtk_dialog_run(GTK_DIALOG (dialog));
  gtk_widget_destroy(dialog);
}
int main(int argc, char *argv[]) {
  GtkWidget *window;
  GtkWidget *about;
  GdkPixbuf *battery;
  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_default_size(GTK_WINDOW(window), 220, 150);
  gtk_window_set_title(GTK_WINDOW(window), "Battery");
  gtk_container_set_border_width(GTK_CONTAINER(window), 15);
  gtk_widget_add_events(window, GDK_BUTTON_PRESS_MASK);
  g_signal_connect(G_OBJECT(window), "button-press-event", 
        G_CALLBACK(show_about), (gpointer) window); 
  g_signal_connect(G_OBJECT(window), "destroy",
        G_CALLBACK(gtk_main_quit), G_OBJECT(window));
  gtk_widget_show_all(window);
  gtk_main();
  return 0;
}

该代码示例使用具有某些功能的GtkAboutDialog。单击窗口的客户区域会弹出对话框。

GtkWidget *dialog = gtk_about_dialog_new();

GtkAboutDialog是使用gtk_about_dialog_new()函数创建的。

gtk_about_dialog_set_name(GTK_ABOUT_DIALOG(dialog), "Battery");
gtk_about_dialog_set_version(GTK_ABOUT_DIALOG(dialog), "0.9"); 
gtk_about_dialog_set_copyright(GTK_ABOUT_DIALOG(dialog), 
    "(c) Jan Bodnar");

这些函数调用设置应用的名称，版本和版权。

gtk_about_dialog_set_comments(GTK_ABOUT_DIALOG(dialog), 
    "Battery is a simple tool for battery checking.");
gtk_about_dialog_set_website(GTK_ABOUT_DIALOG(dialog), 
    "http://www.batteryhq.net");

这些行设置了描述性注释和应用的网站。

GdkPixbuf *pixbuf = gdk_pixbuf_new_from_file("battery.png", NULL);
...
gtk_about_dialog_set_logo(GTK_ABOUT_DIALOG(dialog), pixbuf);
g_object_unref(pixbuf), pixbuf = NULL;

此代码创建应用的徽标。

GTK 对话框 - 图5

图：GtkAboutDialog

`GtkFontSelectionDialog`

GtkFontSelectionDialog是用于选择字体的对话框。它通常用于进行一些文本编辑或格式化的应用中。

fontdialog.c

#include <gtk/gtk.h>
void select_font(GtkWidget *widget, gpointer label) {
  GtkResponseType result;
  GtkWidget *dialog = gtk_font_selection_dialog_new("Select Font");
  result = gtk_dialog_run(GTK_DIALOG(dialog));
  if (result == GTK_RESPONSE_OK || result == GTK_RESPONSE_APPLY) {
     PangoFontDescription *font_desc;
     gchar *fontname = gtk_font_selection_dialog_get_font_name(
                            GTK_FONT_SELECTION_DIALOG(dialog));
     font_desc = pango_font_description_from_string(fontname);
     gtk_widget_modify_font(GTK_WIDGET(label), font_desc);
     g_free(fontname);
   }
  gtk_widget_destroy(dialog);
}
int main(int argc, char *argv[]) {
  GtkWidget *window;
  GtkWidget *label;
  GtkWidget *vbox;
  GtkWidget *toolbar;
  GtkToolItem *font;
  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_default_size(GTK_WINDOW(window), 280, 200);
  gtk_window_set_title(GTK_WINDOW(window), "Font Selection Dialog");
  vbox = gtk_vbox_new(FALSE, 0);
  gtk_container_add(GTK_CONTAINER(window), vbox);
  toolbar = gtk_toolbar_new();
  gtk_toolbar_set_style(GTK_TOOLBAR(toolbar), GTK_TOOLBAR_ICONS);
  gtk_container_set_border_width(GTK_CONTAINER(toolbar), 2);
  font = gtk_tool_button_new_from_stock(GTK_STOCK_SELECT_FONT);
  gtk_toolbar_insert(GTK_TOOLBAR(toolbar), font, -1);
  gtk_box_pack_start(GTK_BOX(vbox), toolbar, FALSE, FALSE, 5);
  label = gtk_label_new("ZetCode");
  gtk_label_set_justify(GTK_LABEL(label), GTK_JUSTIFY_CENTER);
  gtk_box_pack_start(GTK_BOX(vbox), label, TRUE, FALSE, 5);
  g_signal_connect(G_OBJECT(font), "clicked", 
        G_CALLBACK(select_font), label);
  g_signal_connect(G_OBJECT(window), "destroy",
        G_CALLBACK(gtk_main_quit), NULL);
  gtk_widget_show_all(window);
  gtk_main();
  return 0;
}

在代码示例中，我们在窗口中心放置了一个简单标签。我们通过单击工具栏按钮显示一个字体选择对话框。

GtkWidget *dialog = gtk_font_selection_dialog_new("Select Font");
result = gtk_dialog_run(GTK_DIALOG(dialog));

我们使用gtk_font_selection_dialog_new()函数创建GtkFontSelectionDialog，然后使用gtk_dialog_run()函数运行它。

if (result == GTK_RESPONSE_OK || result == GTK_RESPONSE_APPLY) {
    PangoFontDescription *font_desc;
    gchar *fontname = gtk_font_selection_dialog_get_font_name(
                        GTK_FONT_SELECTION_DIALOG(dialog));
    font_desc = pango_font_description_from_string(fontname);
    gtk_widget_modify_font(GTK_WIDGET(label), font_desc);
    g_free(fontname);
}

如果用户单击“确定”或“应用”按钮，则继续。我们使用gtk_font_selection_dialog_get_font_name()函数获得选定的字体名称。然后，将标签的字体更改为选定的字体名称。

GTK 对话框 - 图6

图：GtkFontSelectionDialog

`GtkColorSelectionDialog`

GtkColorSelectionDialog是用于选择颜色的对话框。

colordialog.c

#include <gtk/gtk.h>
void select_font(GtkWidget *widget, gpointer label) {
  GtkResponseType result;
  GtkColorSelection *colorsel;
  GtkWidget *dialog = gtk_color_selection_dialog_new("Font Color");
  result = gtk_dialog_run(GTK_DIALOG(dialog));
  if (result == GTK_RESPONSE_OK) {
    GdkColor color;
    colorsel = GTK_COLOR_SELECTION(
                   GTK_COLOR_SELECTION_DIALOG(dialog)->colorsel);
    gtk_color_selection_get_current_color(colorsel,
                                &color);
    gtk_widget_modify_fg(GTK_WIDGET(label),
                             GTK_STATE_NORMAL,
                             &color);
  } 
  gtk_widget_destroy(dialog);
}
int main(int argc, char *argv[]) {
  GtkWidget *window;
  GtkWidget *widget;
  GtkWidget *label;
  GtkWidget *vbox;
  GtkWidget *toolbar;
  GtkToolItem *font;
  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_default_size(GTK_WINDOW(window), 280, 200);
  gtk_window_set_title(GTK_WINDOW(window), "Color Selection Dialog");
  vbox = gtk_vbox_new(FALSE, 0);
  gtk_container_add(GTK_CONTAINER(window), vbox);
  toolbar = gtk_toolbar_new();
  gtk_toolbar_set_style(GTK_TOOLBAR(toolbar), GTK_TOOLBAR_ICONS);
  gtk_container_set_border_width(GTK_CONTAINER(toolbar), 2);
  font = gtk_tool_button_new_from_stock(GTK_STOCK_SELECT_COLOR);
  gtk_toolbar_insert(GTK_TOOLBAR(toolbar), font, -1);
  gtk_box_pack_start(GTK_BOX(vbox), toolbar, FALSE, FALSE, 5);
  label = gtk_label_new("ZetCode");
  gtk_label_set_justify(GTK_LABEL(label), GTK_JUSTIFY_CENTER);
  gtk_box_pack_start(GTK_BOX(vbox), label, TRUE, FALSE, 5);
  g_signal_connect(G_OBJECT(font), "clicked", 
        G_CALLBACK(select_font), label);
  g_signal_connect(G_OBJECT(window), "destroy",
        G_CALLBACK(gtk_main_quit), NULL);
  gtk_widget_show_all(window);
  gtk_main();
  return 0;
}

该示例与上一个示例非常相似。这次我们更改标签的颜色。

GtkWidget *dialog = gtk_color_selection_dialog_new("Font Color");
result = gtk_dialog_run(GTK_DIALOG(dialog));

我们创建并显示GtkColorSelectionDialog。

if (result == GTK_RESPONSE_OK) {
  GdkColor color;
  colorsel = GTK_COLOR_SELECTION(
                 GTK_COLOR_SELECTION_DIALOG(dialog)->colorsel);
  gtk_color_selection_get_current_color(colorsel,
                 &color);
  gtk_widget_modify_fg(GTK_WIDGET(label),
                 GTK_STATE_NORMAL,
                 &color);
}

如果按“确定”按钮，我们将获得颜色并修改标签的颜色。颜色值通过gtk_color_selection_get_current_color()函数返回。

GTK 对话框 - 图7

图：GtkColorSelectionDialog

本章是关于 GTK+ 中的对话框的。