增加搜索条

我们继续充实我们应用程序的功能。如今，我们添加搜索。GTK+在GtkSearchEntry和Gtksearchbar中支持这个功能。搜索条是一个可以嵌入顶端来展现搜索输入。

我们在头栏增加一个开关按钮，他可以用来滑出头栏下的搜索条。

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <interface>
  3.   <!-- interface-requires gtk+ 3.8 -->
  4.   <template class="ExampleAppWindow" parent="GtkApplicationWindow">
  5.     <property name="title" translatable="yes">Example Application</property>
  6.     <property name="default-width">600</property>
  7.     <property name="default-height">400</property>
  8.     <child>
  9.       <object class="GtkBox" id="content_box">
  10.         <property name="visible">True</property>
  11.         <property name="orientation">vertical</property>
  12.         <child>
  13.           <object class="GtkHeaderBar" id="header">
  14.             <property name="visible">True</property>
  15.             <child type="title">
  16.               <object class="GtkStackSwitcher" id="tabs">
  17.                 <property name="visible">True</property>
  18.                 <property name="margin">6</property>
  19.                 <property name="stack">stack</property>
  20.               </object>
  21.             </child>
  22.             <child>
  23.               <object class="GtkToggleButton" id="search">
  24.                 <property name="visible">True</property>
  25.                 <property name="sensitive">False</property>
  26.                 <style>
  27.                   <class name="image-button"/>
  28.                 </style>
  29.                 <child>
  30.                   <object class="GtkImage" id="search-icon">
  31.                     <property name="visible">True</property>
  32.                     <property name="icon-name">edit-find-symbolic</property>
  33.                     <property name="icon-size">1</property>
  34.                   </object>
  35.                 </child>
  36.               </object>
  37.               <packing>
  38.                 <property name="pack-type">end</property>
  39.               </packing>
  40.             </child>
  41.           </object>
  42.         </child>
  43.         <child>
  44.           <object class="GtkSearchBar" id="searchbar">
  45.             <property name="visible">True</property>
  46.             <child>
  47.               <object class="GtkSearchEntry" id="searchentry">
  48.                 <signal name="search-changed" handler="search_text_changed"/>
  49.                 <property name="visible">True</property>
  50.               </object>
  51.             </child>
  52.           </object>
  53.         </child>
  54.         <child>
  55.           <object class="GtkStack" id="stack">
  56.             <signal name="notify::visible-child" handler="visible_child_changed"/>
  57.             <property name="visible">True</property>
  58.           </object>
  59.         </child>
  60.       </object>
  61.     </child>
  62.   </template>
  63. </interface>

实现搜索条需要更改一点我们还没打算完成的代码。搜索实现的核心是一个监听搜索条文字变化的信号句柄。

  1. ...
  3. static void
  4. search_text_changed (GtkEntry         *entry,
  5.                      ExampleAppWindow *win)
  6. {
  7.   ExampleAppWindowPrivate *priv;
  8.   const gchar *text;
  9.   GtkWidget *tab;
  10.   GtkWidget *view;
  11.   GtkTextBuffer *buffer;
  12.   GtkTextIter start, match_start, match_end;
  14.   text = gtk_entry_get_text (entry);
  16.   if (text[0] == '\0')
  17.     return;
  19.   priv = example_app_window_get_instance_private (win);
  21.   tab = gtk_stack_get_visible_child (GTK_STACK (priv->stack));
  22.   view = gtk_bin_get_child (GTK_BIN (tab));
  23.   buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));
  25.   /* Very simple-minded search implementation */
  26.   gtk_text_buffer_get_start_iter (buffer, &start);
  27.   if (gtk_text_iter_forward_search (&start, text, GTK_TEXT_SEARCH_CASE_INSENSITIVE,
  28.                                     &match_start, &match_end, NULL))
  29.     {
  30.       gtk_text_buffer_select_range (buffer, &match_start, &match_end);
  31.       gtk_text_view_scroll_to_iter (GTK_TEXT_VIEW (view), &match_start,
  32.                                     0.0, FALSE, 0.0, 0.0);
  33.     }
  34. }
  36. static void
  37. example_app_window_init (ExampleAppWindow *win)
  38. {
  40. ...
  42.   gtk_widget_class_bind_template_callback (GTK_WIDGET_CLASS (class), search_text_changed);
  44. ...
  46. }
  48. ...

(full source)

加上了搜索条，我们的应用程序现在是这样的：

getting-started-app7.png