添加搜索栏
我们将继续充实我们的应用程序的功能。现在，我们向其中添加搜索功能。gtkmm通过Gtk::SearchEntry和Gtk::SearchBar对此提供了支持。搜索栏是一个部件，可以从从顶部滑入以显示搜索条目。
我们向标题栏添加了一个开关按钮，可以用于滑出位于标题栏下方的搜索栏。新的部件将添加到window.ui文件中。
实现搜索需要进行大量的代码更改，在此我们不对其进行详细的介绍。实现搜索的核心部分是一个信号处理函数，它监听搜索条目的变更，此处显示的示例没有进行错误处理。
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);
}
}
有了搜索栏后，我们的应用程序看起来像这样：
File: exampleapplication.h (For use with gtkmm 4)
#include "../step4/exampleapplication.h" // Equal to the corresponding file in step4
File: exampleappprefs.h (For use with gtkmm 4)
#include "../step5/exampleappprefs.h" // Equal to the corresponding file in step5
File: exampleappwindow.h (For use with gtkmm 4)
#ifndef GTKMM_EXAMPLEAPPWINDOW_H_
#define GTKMM_EXAMPLEAPPWINDOW_H_
#include <gtkmm.h>
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;
Gtk::ToggleButton* m_search;
Gtk::SearchBar* m_searchbar;
Gtk::SearchEntry* m_searchentry;
Gtk::MenuButton* m_gears;
Glib::RefPtr<Glib::Binding> m_prop_binding;
};
#endif /* GTKMM_EXAMPLEAPPWINDOW_H */
File: main.cc (For use with gtkmm 4)
#include "../step5/main.cc" // Equal to the corresponding file in step5
File: exampleappwindow.cc (For use with gtkmm 4)
#include "exampleappwindow.h"
#include <iostream>
#include <stdexcept>
ExampleAppWindow::ExampleAppWindow(BaseObjectType* cobject,
const Glib::RefPtr<Gtk::Builder>& refBuilder)
: Gtk::ApplicationWindow(cobject),
m_refBuilder(refBuilder),
m_settings(),
m_stack(nullptr),
m_search(nullptr),
m_searchbar(nullptr),
m_searchentry(nullptr),
m_gears(nullptr),
m_prop_binding()
{
// 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");
m_searchentry = m_refBuilder->get_widget<Gtk::SearchEntry>("searchentry");
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);
}
File: exampleappprefs.cc (For use with gtkmm 4)
#include "../step5/exampleappprefs.cc" // Equal to the corresponding file in step5
File: exampleapplication.cc (For use with gtkmm 4)
#include "../step5/exampleapplication.cc" // Equal to the corresponding file in step5
File: window.ui (For use with gtkmm 4)
<?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>