# Ruby GTK 中的对话框 > 原文： [http://zetcode.com/gui/rubygtk/dialogs/](http://zetcode.com/gui/rubygtk/dialogs/) 在 Ruby GTK 编程教程的这一部分中，我们将介绍对话框。 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。对话框是用户与计算机程序之间进行通信的重要手段。 ## `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。 ```rb #!/usr/bin/ruby ''' ZetCode Ruby GTK tutorial This example shows message dialogs. Author: Jan Bodnar Website: www.zetcode.com Last modified: May 2014 ''' require 'gtk3' class RubyApp < Gtk::Window def initialize super init_ui end def init_ui table = Gtk::Table.new 2, 2, true info = Gtk::Button.new :label => "Information" warn = Gtk::Button.new :label => "Warning" ques = Gtk::Button.new :label => "Question" erro = Gtk::Button.new :label => "Error" info.signal_connect "clicked" do on_info end warn.signal_connect "clicked" do on_warn end ques.signal_connect "clicked" do on_ques end erro.signal_connect "clicked" do on_erro end table.attach info, 0, 1, 0, 1 table.attach warn, 1, 2, 0, 1 table.attach ques, 0, 1, 1, 2 table.attach erro, 1, 2, 1, 2 add table set_title "Messages" signal_connect "destroy" do Gtk.main_quit end set_default_size 300, 100 set_window_position :center show_all end def on_info md = Gtk::MessageDialog.new :parent => self, :flags => :destroy_with_parent, :type => :info, :buttons_type => :close, :message => "Download completed" md.run md.destroy end def on_erro md = Gtk::MessageDialog.new :parent => self, :flags => :modal, :type => :error, :buttons_type => :close, :message => "Error loading file" md.run md.destroy end def on_ques md = Gtk::MessageDialog.new :parent => self, :flags => :destroy_with_parent, :type => :question, :buttons_type => :close, :message => "Are you sure to quit?" md.run md.destroy end def on_warn md = Gtk::MessageDialog.new :parent => self, :flags => :destroy_with_parent, :type => :warning, :buttons_type => :close, :message => "Unallowed operation" md.run md.destroy end end Gtk.init window = RubyApp.new Gtk.main ``` 在我们的示例中，我们将显示四种消息对话框：信息，警告，问题和错误消息对话框。 ```rb info = Gtk::Button.new :label => "Information" warn = Gtk::Button.new :label => "Warning" ques = Gtk::Button.new :label => "Question" erro = Gtk::Button.new :label => "Error" ``` 我们有四个按钮。 这些按钮中的每个按钮都会显示不同类型的消息对话框。 ```rb def on_info md = Gtk::MessageDialog.new :parent => self, :flags => :destroy_with_parent, :type => :info, :buttons_type => :close, :message => "Download completed" md.run md.destroy end ``` 如果单击信息按钮，则会显示信息对话框。 `Gtk::MessageDialog::INFO`指定对话框的类型。 `Gtk::MessageDialog::BUTTONS_CLOSE`指定要在对话框中显示的按钮的类型。 最后一个参数是显示的消息。 该对话框使用`run`方法显示。 程序员还必须调用`destroy`或`hide`方法。     ## `AboutDialog` `AboutDialog`显示有关应用的信息。 它可以显示徽标，应用名称，版本，版权，网站或许可证信息。 也有可能对作者，文档撰写者，翻译者和艺术家予以赞扬。 ```rb #!/usr/bin/ruby ''' ZetCode Ruby GTK tutorial This example demonstrates the Gtk::AboutDialog dialog. Author: Jan Bodnar Website: www.zetcode.com Last modified: May 2014 ''' require 'gtk3' class RubyApp < Gtk::Window def initialize super set_title "About dialog" signal_connect "destroy" do Gtk.main_quit end init_ui set_default_size 300, 150 set_window_position :center show_all end def init_ui button = Gtk::Button.new :label => "About" button.set_size_request 80, 30 button.signal_connect "clicked" do on_clicked end fix = Gtk::Fixed.new fix.put button, 20, 20 add fix end def on_clicked about = Gtk::AboutDialog.new about.set_program_name "Battery" about.set_version "0.1" about.set_copyright "(c) Jan Bodnar" about.set_comments "Battery is a simple tool for battery checking" about.set_website "http://www.zetcode.com" begin logo = Gdk::Pixbuf.new :file => "batter.png" about.set_logo logo rescue IOError => e puts e puts "cannot load image" exit end about.run about.destroy end end Gtk.init window = RubyApp.new Gtk.main ``` 该代码示例使用具有某些功能的`Gtk::AboutDialog`。 ```rb about = Gtk::AboutDialog.new ``` 我们创建`Gkt::AboutDialog`小部件。 ```rb about.set_program_name "Battery" about.set_version "0.1" about.set_copyright "(c) Jan Bodnar" ``` 在这里，我们指定名称，版本和版权。 ```rb begin logo = Gdk::Pixbuf.new :file => "batter.png" about.set_logo logo rescue IOError => e puts e puts "cannot load image" exit end ``` 此行为对话框创建徽标。 执行一些错误检查。  图：`Gtk::AboutDialog` ## `Gtk::FontSelectionDialog` `Gtk::FontSelectionDialog`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。 ```rb #!/usr/bin/ruby ''' ZetCode Ruby GTK tutorial This example presents the Gtk::FontSelectionDialog. Author: Jan Bodnar Website: www.zetcode.com Last modified: May 2014 ''' require 'gtk3' class RubyApp < Gtk::Window def initialize super init_ui end def init_ui set_border_width 10 @label = Gtk::Label.new "The only victory over love is flight." button = Gtk::Button.new :label => "Select font" button.signal_connect "clicked" do on_clicked end fix = Gtk::Fixed.new fix.put button, 100, 30 fix.put @label, 30, 90 add fix set_title "Gtk::FontSelectionDialog" signal_connect "destroy" do Gtk.main_quit end set_default_size 300, 150 set_window_position :center show_all end def on_clicked fdia = Gtk::FontChooserDialog.new :title => "Select font name", :parent => nil response = fdia.run if response == Gtk::ResponseType::OK font_desc = Pango::FontDescription.new fdia.font_desc if font_desc @label.override_font font_desc end end fdia.destroy end end Gtk.init window = RubyApp.new Gtk.main ``` 在代码示例中，我们有一个按钮和一个标签。 单击按钮显示`Gtk::FontSelectionDialog`。 ```rb fdia = Gtk::FontSelectionDialog.new "Select font name" ``` 我们创建`GtkFontSelectionDialog`。 ```rb if response == Gtk::ResponseType::OK font_desc = Pango::FontDescription.new fdia.font_desc if font_desc @label.override_font font_desc end end ``` 如果单击“确定”按钮，则标签小部件的字体将更改为我们在对话框中选择的字体。 ## `Gtk::ColorSelectionDialog` `Gtk::ColorSelectionDialog`是用于选择颜色的对话框。 ```rb #!/usr/bin/ruby ''' ZetCode Ruby GTK tutorial This example presents the Gtk::ColorSelectionDialog. Author: Jan Bodnar Website: www.zetcode.com Last modified: May 2014 ''' require 'gtk3' class RubyApp < Gtk::Window def initialize super init_ui end def init_ui set_border_width 10 @label = Gtk::Label.new "The only victory over love is flight." button = Gtk::Button.new :label => "Select colour" button.signal_connect "clicked" do on_clicked end fix = Gtk::Fixed.new fix.put button, 100, 30 fix.put @label, 30, 90 add fix set_title "Gtk::ColorSelectionDialog" signal_connect "destroy" do Gtk.main_quit end set_default_size 350, 150 set_window_position :center show_all end def on_clicked cdia = Gtk::ColorSelectionDialog.new :title => "Select colour" response = cdia.run if response == Gtk::ResponseType::OK colorsel = cdia.color_selection col = colorsel.current_rgba @label.override_color :normal, col end cdia.destroy end end Gtk.init window = RubyApp.new Gtk.main ``` 该示例与上一个示例非常相似。 这次我们更改标签的颜色。 ```rb cdia = Gtk::ColorSelectionDialog.new :title => "Select colour" ``` 我们创建`Gtk::ColorSelectionDialog`。 ```rb if response == Gtk::ResponseType::OK colorsel = cdia.color_selection col = colorsel.current_rgba @label.override_color :normal, col end ``` 如果按“确定”按钮，我们将获得颜色值并修改标签的颜色。  图：`Gtk::ColorSelectionDialog` 在 Ruby GTK 教程的这一部分中，我们介绍了对话框。