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<div class="section">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="sec-buildapp-search-bar"></a>Adding a search bar</h2></div></div></div>
<p>
We continue to flesh out the functionality of our application. For now, we add search.
<span class="application">gtkmm</span> supports this with <code class="classname">Gtk::SearchEntry</code> and <code class="classname">Gtk::SearchBar</code>.
The search bar is a widget that can slide in from the top to present a search entry.
</p>
<p>
We add a toggle button to the header bar, which can be used to slide out the search bar
below the header bar. The new widgets are added in the <code class="filename">window.ui</code> file.
</p>
<p>
Implementing the search needs quite a few code changes that we are not going to completely
go over here. The central piece of the search implementation is a signal handler that
listens for text changes in the search entry, shown here without error handling.
</p>
<pre class="programlisting"><code class="code">void ExampleAppWindow::on_search_text_changed()
{
const auto text = m_searchentry->get_text();
auto tab = dynamic_cast<Gtk::ScrolledWindow*>(m_stack->get_visible_child());
auto view = dynamic_cast<Gtk::TextView*>(tab->get_child());
// Very simple-minded search implementation.
auto buffer = view->get_buffer();
Gtk::TextIter match_start;
Gtk::TextIter match_end;
if (buffer->begin().forward_search(text, Gtk::TextSearchFlags::CASE_INSENSITIVE,
match_start, match_end))
{
buffer->select_range(match_start, match_end);
view->scroll_to(match_start);
}
}
</code></pre>
<p>
With the search bar, our application now looks like this:
</p>
<div class="figure">
<a name="figure-buildapp-search-bar"></a><p class="title"><b>Figure 31.6. Adding a search bar</b></p>
<div class="figure-contents">
<div class="screenshot">
<div class="mediaobject"><img src="figures/buildapp_search_bar.png" alt="Adding a search bar"></div>
</div>
</div>
</div>
<br class="figure-break">
<p><a class="ulink" href="https://gitlab.gnome.org/GNOME/gtkmm-documentation/tree/master/examples/book/buildapp/step6" target="_top">Source Code</a></p>
<p>File: <code class="filename">exampleapplication.h</code> (For use with gtkmm 4)</p>
<pre class="programlisting"><code class="code">#include "../step4/exampleapplication.h"
// Equal to the corresponding file in step4
</code></pre>
<p>File: <code class="filename">exampleappprefs.h</code> (For use with gtkmm 4)</p>
<pre class="programlisting"><code class="code">#include "../step5/exampleappprefs.h"
// Equal to the corresponding file in step5
</code></pre>
<p>File: <code class="filename">exampleappwindow.h</code> (For use with gtkmm 4)</p>
<pre class="programlisting"><code class="code">#ifndef GTKMM_EXAMPLEAPPWINDOW_H_
#define GTKMM_EXAMPLEAPPWINDOW_H_
#include <gtkmm.h>
#define HAS_SEARCH_ENTRY2 GTKMM_CHECK_VERSION(4,13,2)
class ExampleAppWindow : public Gtk::ApplicationWindow
{
public:
ExampleAppWindow(BaseObjectType* cobject,
const Glib::RefPtr<Gtk::Builder>& refBuilder);
static ExampleAppWindow* create();
void open_file_view(const Glib::RefPtr<Gio::File>& file);
protected:
// Signal handlers
void on_search_text_changed();
void on_visible_child_changed();
Glib::RefPtr<Gtk::Builder> m_refBuilder;
Glib::RefPtr<Gio::Settings> m_settings;
Gtk::Stack* m_stack {nullptr};
Gtk::ToggleButton* m_search {nullptr};
Gtk::SearchBar* m_searchbar {nullptr};
#if HAS_SEARCH_ENTRY2
Gtk::SearchEntry2* m_searchentry {nullptr};
#else
Gtk::SearchEntry* m_searchentry {nullptr};
#endif
Gtk::MenuButton* m_gears {nullptr};
Glib::RefPtr<Glib::Binding> m_prop_binding;
};
#endif /* GTKMM_EXAMPLEAPPWINDOW_H */
</code></pre>
<p>File: <code class="filename">exampleapplication.cc</code> (For use with gtkmm 4)</p>
<pre class="programlisting"><code class="code">#include "../step5/exampleapplication.cc"
// Equal to the corresponding file in step5
</code></pre>
<p>File: <code class="filename">exampleappprefs.cc</code> (For use with gtkmm 4)</p>
<pre class="programlisting"><code class="code">#include "../step5/exampleappprefs.cc"
// Equal to the corresponding file in step5
</code></pre>
<p>File: <code class="filename">exampleappwindow.cc</code> (For use with gtkmm 4)</p>
<pre class="programlisting"><code class="code">#include "exampleappwindow.h"
#include <iostream>
#include <stdexcept>
ExampleAppWindow::ExampleAppWindow(BaseObjectType* cobject,
const Glib::RefPtr<Gtk::Builder>& refBuilder)
: Gtk::ApplicationWindow(cobject),
m_refBuilder(refBuilder)
{
// Get widgets from the Gtk::Builder file.
m_stack = m_refBuilder->get_widget<Gtk::Stack>("stack");
if (!m_stack)
throw std::runtime_error("No \"stack\" object in window.ui");
m_search = m_refBuilder->get_widget<Gtk::ToggleButton>("search");
if (!m_search)
throw std::runtime_error("No \"search\" object in window.ui");
m_searchbar = m_refBuilder->get_widget<Gtk::SearchBar>("searchbar");
if (!m_searchbar)
throw std::runtime_error("No \"searchbar\" object in window.ui");
#if HAS_SEARCH_ENTRY2
m_searchentry = m_refBuilder->get_widget<Gtk::SearchEntry2>("searchentry");
#else
m_searchentry = m_refBuilder->get_widget<Gtk::SearchEntry>("searchentry");
#endif
if (!m_searchentry)
throw std::runtime_error("No \"searchentry\" object in window.ui");
m_gears = m_refBuilder->get_widget<Gtk::MenuButton>("gears");
if (!m_gears)
throw std::runtime_error("No \"gears\" object in window.ui");
// Bind settings.
m_settings = Gio::Settings::create("org.gtkmm.exampleapp");
m_settings->bind("transition", m_stack->property_transition_type());
// Bind properties.
m_prop_binding = Glib::Binding::bind_property(m_search->property_active(),
m_searchbar->property_search_mode_enabled(), Glib::Binding::Flags::BIDIRECTIONAL);
// Connect signal handlers.
m_searchentry->signal_search_changed().connect(
sigc::mem_fun(*this, &ExampleAppWindow::on_search_text_changed));
m_stack->property_visible_child().signal_changed().connect(
sigc::mem_fun(*this, &ExampleAppWindow::on_visible_child_changed));
// Connect the menu to the MenuButton m_gears.
// (The connection between action and menu item is specified in gears_menu.ui.)
auto menu_builder = Gtk::Builder::create_from_resource("/org/gtkmm/exampleapp/gears_menu.ui");
auto menu = menu_builder->get_object<Gio::MenuModel>("menu");
if (!menu)
throw std::runtime_error("No \"menu\" object in gears_menu.ui");
m_gears->set_menu_model(menu);
}
//static
ExampleAppWindow* ExampleAppWindow::create()
{
// Load the Builder file and instantiate its widgets.
auto refBuilder = Gtk::Builder::create_from_resource("/org/gtkmm/exampleapp/window.ui");
auto window = Gtk::Builder::get_widget_derived<ExampleAppWindow>(refBuilder, "app_window");
if (!window)
throw std::runtime_error("No \"app_window\" object in window.ui");
return window;
}
void ExampleAppWindow::open_file_view(const Glib::RefPtr<Gio::File>& file)
{
const Glib::ustring basename = file->get_basename();
auto scrolled = Gtk::make_managed<Gtk::ScrolledWindow>();
scrolled->set_expand(true);
auto view = Gtk::make_managed<Gtk::TextView>();
view->set_editable(false);
view->set_cursor_visible(false);
scrolled->set_child(*view);
m_stack->add(*scrolled, basename, basename);
auto buffer = view->get_buffer();
try
{
char* contents = nullptr;
gsize length = 0;
file->load_contents(contents, length);
buffer->set_text(contents, contents+length);
g_free(contents);
}
catch (const Glib::Error& ex)
{
std::cout << "ExampleAppWindow::open_file_view(\"" << file->get_parse_name()
<< "\"):\n " << ex.what() << std::endl;
return;
}
auto tag = buffer->create_tag();
m_settings->bind("font", tag->property_font());
buffer->apply_tag(tag, buffer->begin(), buffer->end());
m_search->set_sensitive(true);
}
void ExampleAppWindow::on_search_text_changed()
{
const auto text = m_searchentry->get_text();
if (text.empty())
return;
auto tab = dynamic_cast<Gtk::ScrolledWindow*>(m_stack->get_visible_child());
if (!tab)
{
std::cout << "ExampleAppWindow::on_search_text_changed(): No visible child." << std::endl;
return;
}
auto view = dynamic_cast<Gtk::TextView*>(tab->get_child());
if (!view)
{
std::cout << "ExampleAppWindow::on_search_text_changed(): No visible text view." << std::endl;
return;
}
// Very simple-minded search implementation.
auto buffer = view->get_buffer();
Gtk::TextIter match_start;
Gtk::TextIter match_end;
if (buffer->begin().forward_search(text, Gtk::TextSearchFlags::CASE_INSENSITIVE,
match_start, match_end))
{
buffer->select_range(match_start, match_end);
view->scroll_to(match_start);
}
}
void ExampleAppWindow::on_visible_child_changed()
{
m_searchbar->set_search_mode(false);
}
</code></pre>
<p>File: <code class="filename">main.cc</code> (For use with gtkmm 4)</p>
<pre class="programlisting"><code class="code">#include "exampleapplication.h"
#include "exampleappwindow.h"
int main(int argc, char* argv[])
{
#if HAS_SEARCH_ENTRY2
// A GtkSearchEntry (e.g. from window.ui) shall be wrapped in
// a Gtk::SearhcEntry2 and not in a deprecated Gtk::SearchEntry.
Gtk::Application::wrap_in_search_entry2(true);
#endif
// Since this example is running uninstalled, we have to help it find its
// schema. This is *not* necessary in a properly installed application.
Glib::setenv ("GSETTINGS_SCHEMA_DIR", ".", false);
auto application = ExampleApplication::create();
// Start the application, showing the initial window,
// and opening extra views for any files that it is asked to open,
// for instance as a command-line parameter.
// run() will return when the last window has been closed.
return application->run(argc, argv);
}
</code></pre>
<p>File: <code class="filename">window.ui</code> (For use with gtkmm 4)</p>
<pre class="programlisting"><code class="code"><?xml version="1.0" encoding="UTF-8"?>
<interface>
<object class="GtkApplicationWindow" id="app_window">
<property name="title" translatable="yes">Example Application</property>
<property name="default-width">600</property>
<property name="default-height">400</property>
<property name="hide-on-close">True</property>
<child type="titlebar">
<object class="GtkHeaderBar" id="header">
<child type="title">
<object class="GtkStackSwitcher" id="tabs">
<property name="stack">stack</property>
</object>
</child>
<child type="end">
<object class="GtkMenuButton" id="gears">
<property name="direction">none</property>
</object>
</child>
<child type="end">
<object class="GtkToggleButton" id="search">
<property name="sensitive">False</property>
<property name="icon-name">edit-find-symbolic</property>
</object>
</child>
</object>
</child>
<child>
<object class="GtkBox" id="content_box">
<property name="orientation">vertical</property>
<child>
<object class="GtkSearchBar" id="searchbar">
<child>
<object class="GtkSearchEntry" id="searchentry">
</object>
</child>
</object>
</child>
<child>
<object class="GtkStack" id="stack">
<property name="transition-duration">500</property>
</object>
</child>
</object>
</child>
</object>
</interface>
</code></pre>
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