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<div class="sect1">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="sec-progressbar"></a>ProgressBar</h2></div></div></div>
<p>
Progress bars are used to show the status of an ongoing operation. For
instance, a <code class="classname">ProgressBar</code> can show how much of a task has
been completed.
</p>
<p>
To change the value shown, use the <code class="methodname">set_fraction()</code> method,
passing a <span class="type">double</span> between 0.0 and 1.0 to provide the new percentage.
</p>
<p>
A <code class="classname">ProgressBar</code> is horizontal and left-to-right by default,
but you can change it to a vertical progress bar by using the
<code class="methodname">set_orientation()</code> method.
</p>
<p><a class="ulink" href="http://developer.gnome.org/gtkmm/3.24/classGtk_1_1ProgressBar.html" target="_top">Reference</a></p>
<div class="sect2">
<div class="titlepage"><div><div><h3 class="title">
<a name="progressbar-activity-mode"></a>Activity Mode</h3></div></div></div>
<p>
Besides indicating the amount of progress that has occured, the
progress bar can also be used to indicate that there is some activity;
this is done by placing the progress bar in <span class="emphasis"><em>activity mode</em></span>. In
this mode, the progress bar displays a small rectangle which moves
back and forth. Activity mode is useful in situations where the
progress of an operation cannot be calculated as a value range (e.g.,
receiving a file of unknown length).
</p>
<p>
To do this, you need to call the <code class="methodname">pulse()</code> method at regular
intervals. You can also choose the step size, with the
<code class="methodname">set_pulse_step()</code> method.
</p>
<p>
The progress bar can also display a configurable text
string within its trough, using the <code class="methodname">set_text()</code> method.
</p>
</div>
<div class="sect2">
<div class="titlepage"><div><div><h3 class="title">
<a name="progressbar-example"></a>Example</h3></div></div></div>
<div class="figure">
<a name="figure-progressbar"></a><p class="title"><b>Figure 7.7. ProgressBar</b></p>
<div class="figure-contents"><div class="screenshot"><div><img src="figures/progressbar.png" alt="ProgressBar"></div></div></div>
</div>
<br class="figure-break"><p><a class="ulink" href="http://git.gnome.org/browse/gtkmm-documentation/tree/examples/book/progressbar?h=gtkmm-3-24" target="_top">Source Code</a></p>
<p>File: <code class="filename">examplewindow.h</code> (For use with gtkmm 3, not gtkmm 2)
</p>
<pre class="programlisting">
#ifndef GTKMM_EXAMPLEWINDOW_H
#define GTKMM_EXAMPLEWINDOW_H
#include <gtkmm.h>
class ExampleWindow : public Gtk::Window
{
public:
ExampleWindow();
virtual ~ExampleWindow();
protected:
//Signal handlers:
void on_checkbutton_text();
void on_checkbutton_activity();
void on_checkbutton_inverted();
bool on_timeout();
void on_button_close();
//Child widgets:
Gtk::Box m_VBox;
Gtk::Grid m_Grid;
Gtk::ProgressBar m_ProgressBar;
Gtk::Separator m_Separator;
Gtk::CheckButton m_CheckButton_Text, m_CheckButton_Activity, m_CheckButton_Inverted;
Gtk::Button m_Button_Close;
sigc::connection m_connection_timeout;
bool m_bActivityMode;
};
#endif //GTKMM_EXAMPLEWINDOW_H
</pre>
<p>File: <code class="filename">main.cc</code> (For use with gtkmm 3, not gtkmm 2)
</p>
<pre class="programlisting">
#include "examplewindow.h"
#include <gtkmm/application.h>
int main(int argc, char *argv[])
{
auto app = Gtk::Application::create(argc, argv, "org.gtkmm.example");
ExampleWindow window;
//Shows the window and returns when it is closed.
return app->run(window);
}
</pre>
<p>File: <code class="filename">examplewindow.cc</code> (For use with gtkmm 3, not gtkmm 2)
</p>
<pre class="programlisting">
#include "examplewindow.h"
#include <iostream>
ExampleWindow::ExampleWindow()
: m_VBox(Gtk::ORIENTATION_VERTICAL, 5),
m_CheckButton_Text("Show text"),
m_CheckButton_Activity("Activity mode"),
m_CheckButton_Inverted("Right to Left"),
m_Button_Close("Close"),
m_bActivityMode(false)
{
set_resizable();
set_title("Gtk::ProgressBar");
m_VBox.set_border_width(10);
add(m_VBox);
m_VBox.pack_start(m_ProgressBar, Gtk::PACK_SHRINK, 5);
m_ProgressBar.set_halign(Gtk::ALIGN_CENTER);
m_ProgressBar.set_valign(Gtk::ALIGN_CENTER);
m_ProgressBar.set_text("some text");
m_ProgressBar.set_show_text(false);
//Add a timer callback to update the value of the progress bar:
m_connection_timeout = Glib::signal_timeout().connect(sigc::mem_fun(*this,
&ExampleWindow::on_timeout), 50 );
m_VBox.pack_start(m_Separator, Gtk::PACK_SHRINK);
m_VBox.pack_start(m_Grid);
m_Grid.set_row_homogeneous(true);
//Add a check button to select displaying of the trough text:
m_Grid.attach(m_CheckButton_Text, 0, 0, 1, 1);
m_CheckButton_Text.property_margin() = 5;
m_CheckButton_Text.signal_clicked().connect(sigc::mem_fun(*this,
&ExampleWindow::on_checkbutton_text) );
//Add a check button to toggle activity mode:
m_Grid.attach(m_CheckButton_Activity, 0, 1, 1, 1);
m_CheckButton_Activity.property_margin() = 5;
m_CheckButton_Activity.signal_clicked().connect(sigc::mem_fun(*this,
&ExampleWindow::on_checkbutton_activity) );
//Add a check button to select growth from left to right or from right to left:
m_Grid.attach(m_CheckButton_Inverted, 0, 2, 1, 1);
m_CheckButton_Inverted.property_margin() = 5;
m_CheckButton_Inverted.signal_clicked().connect(sigc::mem_fun(*this,
&ExampleWindow::on_checkbutton_inverted) );
//Add a button to exit the program.
m_VBox.pack_start(m_Button_Close, Gtk::PACK_SHRINK);
m_Button_Close.signal_clicked().connect(sigc::mem_fun(*this,
&ExampleWindow::on_button_close) );
m_Button_Close.set_can_default();
m_Button_Close.grab_default();
show_all_children();
}
ExampleWindow::~ExampleWindow()
{
}
void ExampleWindow::on_checkbutton_text()
{
const bool show_text = m_CheckButton_Text.get_active();
m_ProgressBar.set_show_text(show_text);
}
void ExampleWindow::on_checkbutton_activity()
{
m_bActivityMode = m_CheckButton_Activity.get_active();
if(m_bActivityMode)
m_ProgressBar.pulse();
else
m_ProgressBar.set_fraction(0.0);
}
void ExampleWindow::on_checkbutton_inverted()
{
const bool inverted = m_CheckButton_Inverted.get_active();
m_ProgressBar.set_inverted(inverted);
}
void ExampleWindow::on_button_close()
{
hide();
}
/* Update the value of the progress bar so that we get
* some movement */
bool ExampleWindow::on_timeout()
{
if(m_bActivityMode)
m_ProgressBar.pulse();
else
{
double new_val = m_ProgressBar.get_fraction() + 0.01;
if(new_val > 1.0)
new_val = 0.0;
//Set the new value:
m_ProgressBar.set_fraction(new_val);
}
//As this is a timeout function, return true so that it
//continues to get called
return true;
}
</pre>
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