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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"><HTML><HEAD><TITLE>单选按钮 Radio Buttons</TITLE><METANAME="GENERATOR"CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+"><LINKREL="HOME"TITLE="GTK+ 2.0 教程"HREF="book1.html"><LINKREL="UP"TITLE="按钮构件"HREF="c554.html"><LINKREL="PREVIOUS"TITLE="复选按钮 Check Buttons"HREF="x600.html"><LINKREL="NEXT"TITLE="调整对象 Adjustments"HREF="c628.html"></HEAD><BODYCLASS="SECT1"BGCOLOR="#FFFFFF"TEXT="#000000"LINK="#0000FF"VLINK="#840084"ALINK="#0000FF"><DIVCLASS="NAVHEADER"><TABLESUMMARY="Header navigation table"WIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><THCOLSPAN="3"ALIGN="center">GTK+ 2.0 教程</TH></TR><TR><TDWIDTH="10%"ALIGN="left"VALIGN="bottom"><AHREF="x600.html"ACCESSKEY="P"><<< Previous</A></TD><TDWIDTH="80%"ALIGN="center"VALIGN="bottom">按钮构件</TD><TDWIDTH="10%"ALIGN="right"VALIGN="bottom"><AHREF="c628.html"ACCESSKEY="N">Next >>></A></TD></TR></TABLE><HRALIGN="LEFT"WIDTH="100%"></DIV><DIVCLASS="SECT1"><H1CLASS="SECT1"><ANAME="SEC-RADIOBUTTONS">单选按钮 Radio Buttons</H1><P>单选按钮与复选按钮相似，只是单选按钮是分组的，在一组中只有一个处于选中/按下状态。这在你的应用程序中要从几个选项中选一个的地方可以用到。</P><P>用这些调用之一来创建一个新的单选按钮：</P><TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><PRECLASS="PROGRAMLISTING">GtkWidget *gtk_radio_button_new( GSList *group );GtkWidget *gtk_radio_button_new_from_widget( GtkRadioButton *group );GtkWidget *gtk_radio_button_new_with_label( GSList *group, const gchar *label );GtkWidget* gtk_radio_button_new_with_label_from_widget( GtkRadioButton *group, const gchar *label );GtkWidget *gtk_radio_button_new_with_mnemonic( GSList *group, const gchar *label );GtkWidget *gtk_radio_button_new_with_mnemonic_from_widget( GtkRadioButton *group, const gchar *label ); </PRE></TD></TR></TABLE><P>你可能注意到了，这些调用有个额外的参数。它们需要一个组以正常运作。第一次调用 gtk_radio_button_new() 或 gtk_radio_button_new_with_label() 应该传递 NULL 值作为第一个参数。接着用如下函数创建一个组：</P><TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><PRECLASS="PROGRAMLISTING">GSList *gtk_radio_button_get_group( GtkRadioButton *radio_button );</PRE></TD></TR></TABLE><P>有一点很重要，必须为每个添加到组的新按钮调用 gtk_radio_button_get_group()，并把前一个按钮作为参数。返回的结果再传给下一个调用 gtk_radio_button_new() 或 gtk_radio_button_new_with_label()。这样才能建立连锁的按钮。看一下下面的示例会更清楚一些。</P><P>你可以使用下面的语法来稍微缩短上面的步骤，它不需要一个变量来存储按钮列表：</P><TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><PRECLASS="PROGRAMLISTING"> button2 = gtk_radio_button_new_with_label( gtk_radio_button_get_group (GTK_RADIO_BUTTON (button1)), "button2");</PRE></TD></TR></TABLE><P>而 _from_widget() 创建函数可以让你做得更简洁些，它完全省略了 gtk_radio_button_get_group() 调用。在下面示例的第三个按钮就是用这种方法创建的。</P><TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><PRECLASS="PROGRAMLISTING"> button2 = gtk_radio_button_new_with_label_from_widget( GTK_RADIO_BUTTON (button1), "button2");</PRE></TD></TR></TABLE><P>明确地指定哪个按钮应该被默认按下也是个好主意，用：</P><TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><PRECLASS="PROGRAMLISTING">void gtk_toggle_button_set_active( GtkToggleButton *toggle_button, gboolean state );</PRE></TD></TR></TABLE><P>这在开关按钮部分描述过，在这里它也确切地以同样的方式工作。多个单选按钮组合到一起后，组中一次只能有一个被激活。如果用户点击一个单选按钮，接着点另一个，第一个单选按钮会首先发出 "toggled" 信号 (以报告变得不激活了)，然后第二个也会发出 "toggled" 信号 (以报告变得激活了)。</P><P>下面的示例创建一个含三个按钮的单选按钮组。</P><P><SPANCLASS="INLINEMEDIAOBJECT"><IMGSRC="images/radiobuttons.png"></SPAN></P><TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><PRECLASS="PROGRAMLISTING"> #include <glib.h>#include <gtk/gtk.h>gint close_application( GtkWidget *widget, GdkEvent *event, gpointer data ){ gtk_main_quit (); return FALSE;}int main( int argc, char *argv[] ){ GtkWidget *window = NULL; GtkWidget *box1; GtkWidget *box2; GtkWidget *button; GtkWidget *separator; GSList *group; gtk_init (&argc, &argv); window = gtk_window_new (GTK_WINDOW_TOPLEVEL); g_signal_connect (G_OBJECT (window), "delete_event", G_CALLBACK (close_application), NULL); gtk_window_set_title (GTK_WINDOW (window), "radio buttons"); gtk_container_set_border_width (GTK_CONTAINER (window), 0); box1 = gtk_vbox_new (FALSE, 0); gtk_container_add (GTK_CONTAINER (window), box1); gtk_widget_show (box1); box2 = gtk_vbox_new (FALSE, 10); gtk_container_set_border_width (GTK_CONTAINER (box2), 10); gtk_box_pack_start (GTK_BOX (box1), box2, TRUE, TRUE, 0); gtk_widget_show (box2); button = gtk_radio_button_new_with_label (NULL, "button1"); gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0); gtk_widget_show (button); group = gtk_radio_button_get_group (GTK_RADIO_BUTTON (button)); button = gtk_radio_button_new_with_label (group, "button2"); gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (button), TRUE); gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0); gtk_widget_show (button); button = gtk_radio_button_new_with_label_from_widget (GTK_RADIO_BUTTON (button), "button3"); gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0); gtk_widget_show (button); separator = gtk_hseparator_new (); gtk_box_pack_start (GTK_BOX (box1), separator, FALSE, TRUE, 0); gtk_widget_show (separator); box2 = gtk_vbox_new (FALSE, 10); gtk_container_set_border_width (GTK_CONTAINER (box2), 10); gtk_box_pack_start (GTK_BOX (box1), box2, FALSE, TRUE, 0); gtk_widget_show (box2); button = gtk_button_new_with_label ("close"); g_signal_connect_swapped (G_OBJECT (button), "clicked", G_CALLBACK (close_application), window); gtk_box_pack_start (GTK_BOX (box2), button, TRUE, TRUE, 0); GTK_WIDGET_SET_FLAGS (button, GTK_CAN_DEFAULT); gtk_widget_grab_default (button); gtk_widget_show (button); gtk_widget_show (window); gtk_main (); return 0;}</PRE></TD></TR></TABLE></DIV><DIVCLASS="NAVFOOTER"><HRALIGN="LEFT"WIDTH="100%"><TABLESUMMARY="Footer navigation table"WIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top"><AHREF="x600.html"ACCESSKEY="P"><<< Previous</A></TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><AHREF="book1.html"ACCESSKEY="H">Home</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top"><AHREF="c628.html"ACCESSKEY="N">Next >>></A></TD></TR><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top">复选按钮 Check Buttons</TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><AHREF="c554.html"ACCESSKEY="U">Up</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top">调整对象 Adjustments</TD></TR></TABLE></DIV></BODY></HTML>⌨️ 快捷键说明
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