<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Widgets</title> <link rel="stylesheet" type="text/css" href="style.css"> <meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> <link rel="home" href="index.html" title="Programming with gtkmm 3"> <link rel="up" href="chapter-basics.html" title="Chapter 3. Basics"> <link rel="prev" href="sec-headers-and-linking.html" title="Headers and Linking"> <link rel="next" href="sec-signals-overview.html" title="Signals"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <div class="navheader"> <table width="100%" summary="Navigation header"> <tr><th colspan="3" align="center">Widgets</th></tr> <tr> <td width="20%" align="left"> <a accesskey="p" href="sec-headers-and-linking.html"><img src="icons/prev.png" alt="Prev"></a> </td> <th width="60%" align="center">Chapter 3. Basics</th> <td width="20%" align="right"> <a accesskey="n" href="sec-signals-overview.html"><img src="icons/next.png" alt="Next"></a> </td> </tr> </table> <hr> </div> <div class="sect1"> <div class="titlepage"><div><div><h2 class="title" style="clear: both"> <a name="sec-widgets-overview"></a>Widgets</h2></div></div></div> <p><span class="application">gtkmm</span> applications consist of windows containing widgets, such as buttons and text boxes. In some other systems, widgets are called "controls". For each widget in your application's windows, there is a C++ object in your application's code. So you just need to call a method of the widget's class to affect the visible widget.</p> <p>Widgets are arranged inside container widgets such as frames and notebooks, in a hierarchy of widgets within widgets. Some of these container widgets, such as <code class="classname">Gtk::Grid</code>, are not visible - they exist only to arrange other widgets. Here is some example code that adds 2 <code class="classname">Gtk::Button</code> widgets to a <code class="classname">Gtk::Box</code> container widget: </p> <pre class="programlisting">m_box.pack_start(m_Button1); m_box.pack_start(m_Button2);</pre> <p> and here is how to add the <code class="classname">Gtk::Box</code>, containing those buttons, to a <code class="classname">Gtk::Frame</code>, which has a visible frame and title: </p> <pre class="programlisting">m_frame.add(m_box);</pre> <p> </p> <p> Most of the chapters in this book deal with specific widgets. See the <a class="link" href="chapter-container-widgets.html" title="Chapter 8. Container Widgets">Container Widgets</a> section for more details about adding widgets to container widgets. </p> <p>Although you can specify the layout and appearance of windows and widgets with C++ code, you will probably find it more convenient to design your user interfaces with <code class="literal">Glade</code> and load them at runtime with <code class="literal">Gtk::Builder</code>. See the <a class="link" href="chapter-builder.html" title="Chapter 26. Glade and Gtk::Builder">Glade and Gtk::Builder</a> chapter. </p> <p>Although <span class="application">gtkmm</span> widget instances have lifetimes and scopes just like those of other C++ classes, <span class="application">gtkmm</span> has an optional time-saving feature that you will see in some of the examples. The <code class="function">Gtk::make_managed()</code> allows you to create a new widget and state that it will become owned by the container into which you place it. This allows you to create the widget, add it to the container and not be concerned about deleting it, since that will occur when the parent container (which may itself be managed) is deleted. You can learn more about <span class="application">gtkmm</span> memory management techniques in the <a class="link" href="chapter-memory.html" title="Chapter 25. Memory management">Memory Management chapter</a>. </p> </div> <div class="navfooter"> <hr> <table width="100%" summary="Navigation footer"> <tr> <td width="40%" align="left"> <a accesskey="p" href="sec-headers-and-linking.html"><img src="icons/prev.png" alt="Prev"></a> </td> <td width="20%" align="center"><a accesskey="u" href="chapter-basics.html"><img src="icons/up.png" alt="Up"></a></td> <td width="40%" align="right"> <a accesskey="n" href="sec-signals-overview.html"><img src="icons/next.png" alt="Next"></a> </td> </tr> <tr> <td width="40%" align="left" valign="top">Headers and Linking </td> <td width="20%" align="center"><a accesskey="h" href="index.html"><img src="icons/home.png" alt="Home"></a></td> <td width="40%" align="right" valign="top"> Signals</td> </tr> </table> </div> </body> </html>
