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<HTML><HEAD><TITLE>Toggle Buttons</TITLE><METANAME="GENERATOR"CONTENT="Modular DocBook HTML Stylesheet Version 1.49"><LINKREL="HOME"TITLE="GTK+ 1.2 Tutorial"HREF="gtk-tut.html"><LINKREL="UP"TITLE="The Button Widget"HREF="ch-buttonwidget.html"><LINKREL="PREVIOUS"TITLE="The Button Widget"HREF="ch-buttonwidget.html"><LINKREL="NEXT"TITLE="Check Buttons"HREF="sec-checkbuttons.html"></HEAD></head><body bgcolor="#FFFFFF" marginheight=0 marginwidth=0 width="100%"><table cellspacing=6 border=0 cellpadding=0 width="100%"> <tr> <td bgcolor="#FFFFFF" valign=top nowrap> <centeR><A HREF="/"><img src="/images/gtk-logo-rgb.gif" width=107 height=140 border=0></A> <font face="helvetica,lucidia" color="#000000"><BR><BR><b>GTK+<BR>The GIMP Toolkit</b></center><BR><table width=100% cellspacing=0 cellpadding=2 border=0><tr><td bgcolor="#000000"><table width=100% cellspacing=0 cellpadding=4 border=0><tr><td bgcolor="#AAAAEE" nowrap><B>General</B></td></tr><tr><td bgcolor="#FFFFFF" nowrap><A HREF="/">Introduction</A><BR><A HREF="/screenshots/">Screenshots</A><br><A HREF="/download/">Download</A><br><A HREF="/mailinglists.html">Mailing Lists</A><BR><A HREF="/bindings.html">Language Bindings</A><BR><A HREF="http://gtk.themes.org/">Themes</A><BR><A HREF="/bugs.html">Bug Tracker</A><BR></td></tr></table></td></tr></table><BR> <table width=100% cellspacing=0 cellpadding=2 border=0><tr><td bgcolor="#000000"><table width=100% cellspacing=0 cellpadding=4 border=0><tr><td bgcolor="#AAAAEE" nowrap><B>Documentation</B></td></tr><tr><td bgcolor="#FFFFFF" nowrap><A HREF="/faq/">FAQ</A><br><A HREF="/tutorial/">Tutorial</A><BR><A HREF="/api/">API Reference</A><br><A HREF="/books.html">Published Books</A><BR></td></tr></table></td></tr></table><BR> <table width=100% cellspacing=0 cellpadding=2 border=0><tr><td bgcolor="#000000"><table width=100% cellspacing=0 cellpadding=4 border=0><tr><td bgcolor="#AAAAEE" nowrap><B>Projects</B></td></tr><tr><td bgcolor="#FFFFFF" nowrap><A HREF="http://www.pango.org/">Pango</A><BR><A HREF="http://sources.redhat.com/inti/">Inti</A><BR><A HREF="http://www.gnome.org/">GNOME</A><BR><A HREF="http://user.sgic.fi/~tml/gimp/win32/">GTK+ for Win32</A><br><A HREF="http://people.redhat.com/sopwith/gtkfb/">GtkFB (Framebuffer)</A><br><A HREF="http://www.directfb.org/gtk.xml">GTK+ on DirectFB</A><BR><A HREF="/beos/">GTK+ for BeOS</A></td></tr></table></td></tr></table><BR> <table width=100% cellspacing=0 cellpadding=2 border=0><tr><td bgcolor="#000000"><table width=100% cellspacing=0 cellpadding=4 border=0><tr><td bgcolor="#AAAAEE" nowrap><B><B>Applications</B></B></td></tr><tr><td bgcolor="#FFFFFF" nowrap><A HREF="http://www.gimp.org/">GIMP</A><BR><A HREF="http://www.abiword.org/">Abiword</A><BR><A HREF="http://www.lysator.liu.se/~alla/dia/dia.html">Dia</A><BR><A HREF="http://glade.pn.org/">Glade</A><BR><A HREF="http://www.gnucash.org/">GnuCash</A><BR><A HREF="http://www.gnome.org/projects/gnumeric/">Gnumeric</A><BR><BR><A HREF="http://www.gnome.org/applist/">GNOME Software Map</A><br></td></tr></table></td></tr></table><BR> </td> <td bgcolor="#ffffff" valign=top width="99%"><font face="lucida,helvetica"><BODYCLASS="SECT1"BGCOLOR="#FFFFFF"TEXT="#000000"LINK="#0000FF"VLINK="#840084"ALINK="#0000FF"><DIVCLASS="NAVHEADER"><TABLEWIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><THCOLSPAN="3"ALIGN="center">GTK+ 1.2 Tutorial</TH></TR><TR><TDWIDTH="10%"ALIGN="left"VALIGN="bottom"><AHREF="ch-buttonwidget.html"><<< Previous</A></TD><TDWIDTH="80%"ALIGN="center"VALIGN="bottom">Chapter 6. The Button Widget</TD><TDWIDTH="10%"ALIGN="right"VALIGN="bottom"><AHREF="sec-checkbuttons.html">Next >>></A></TD></TR></TABLE><HRALIGN="LEFT"WIDTH="100%"></DIV><DIVCLASS="SECT1"><H1CLASS="SECT1"><ANAME="SEC-TOGGLEBUTTONS">6.2. Toggle Buttons</A></H1><P>Toggle buttons are derived from normal buttons and are very similar,except they will always be in one of two states, alternated by aclick. They may be depressed, and when you click again, they will popback up. Click again, and they will pop back down.</P><P>Toggle buttons are the basis for check buttons and radio buttons, assuch, many of the calls used for toggle buttons are inherited by radioand check buttons. I will point these out when we come to them.</P><P>Creating a new toggle button:</P><TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><PRECLASS="PROGRAMLISTING">GtkWidget *gtk_toggle_button_new( void );GtkWidget *gtk_toggle_button_new_with_label( gchar *label );</PRE></TD></TR></TABLE><P>As you can imagine, these work identically to the normal button widgetcalls. The first creates a blank toggle button, and the second, abutton with a label widget already packed into it.</P><P>To retrieve the state of the toggle widget, including radio and checkbuttons, we use a construct as shown in our example below. This teststhe state of the toggle, by accessing the <TTCLASS="LITERAL">active</TT> field of thetoggle widget's structure, after first using the<TTCLASS="LITERAL">GTK_TOGGLE_BUTTON</TT> macro to cast the widget pointer into a togglewidget pointer. The signal of interest to us emitted by togglebuttons (the toggle button, check button, and radio button widgets) isthe "toggled" signal. To check the state of these buttons, set up asignal handler to catch the toggled signal, and access the structureto determine its state. The callback will look something like:</P><TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><PRECLASS="PROGRAMLISTING">void toggle_button_callback (GtkWidget *widget, gpointer data){ if (GTK_TOGGLE_BUTTON (widget)->active) { /* If control reaches here, the toggle button is down */ } else { /* If control reaches here, the toggle button is up */ }}</PRE></TD></TR></TABLE><P>To force the state of a toggle button, and its children, the radio andcheck buttons, use this function:</P><TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><PRECLASS="PROGRAMLISTING">void gtk_toggle_button_set_active( GtkToggleButton *toggle_button, gint state );</PRE></TD></TR></TABLE><P>The above call can be used to set the state of the toggle button, andits children the radio and check buttons. Passing in your createdbutton as the first argument, and a TRUE or FALSE for the second stateargument to specify whether it should be down (depressed) or up(released). Default is up, or FALSE.</P><P>Note that when you use the gtk_toggle_button_set_active() function, andthe state is actually changed, it causes the "clicked" and "toggled"signals to be emitted from the button.</P><TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><PRECLASS="PROGRAMLISTING">gboolean gtk_toggle_button_get_active (GtkToggleButton *toggle_button);</PRE></TD></TR></TABLE><P>This returns the current state of the toggle button as a booleanTRUE/FALSE value.</P></DIV><DIVCLASS="NAVFOOTER"><HRALIGN="LEFT"WIDTH="100%"><TABLEWIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top"><AHREF="ch-buttonwidget.html"><<< Previous</A></TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><AHREF="gtk-tut.html">Home</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top"><AHREF="sec-checkbuttons.html">Next >>></A></TD></TR><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top">The Button Widget</TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><AHREF="ch-buttonwidget.html">Up</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top">Check Buttons</TD></TR></TABLE></DIV> </td> </tr></table> </td> </tr></table></body></BODY></HTML>⌨️ 快捷键说明
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