我有两个切换按钮，分别名为 RUN 和 KILL。当我打开（即按下）RUN 按钮时，我只想通过按下 KILL 切换按钮（而不是通过关闭 RUN 按钮）来关闭它。除非按下 KILL 按钮，否则我希望随后在 RUN 按钮上单击鼠标什么都不做。同样，当 KILL 按钮打开时，我只想通过按下 RUN 按钮来关闭它（同样，不是通过关闭 KILL 按钮）。我不确定如何构建将这两个切换按钮的操作绑定在一起的事件处理程序。我正在使用 GTK+ 和 Glade 并用 C 编程。
【问题讨论】：
由于GtkToggleButton 是一个通用按钮，它会随着所有用户交互而切换，我们必须防止它在某些条件下切换。在这种情况下，切换后的按钮不能在其自身上再次切换，而是通过另一个切换按钮。为此，您必须：
要实现 1) 我们可以将回调连接到 GtkWidget "button-press-event" 信号并根据所需条件返回，TRUE 阻止信号传播，否则为 FALSE。
然后，为了处理 2)，我们可以使用带有 G_BINDING_INVERTED_BOOLEAN 标志的 GtkToggleButton "active" 属性的 g_object_bind_property 来获得所需的行为。请注意，我们必须将其中一个设置为激活状态。
所以，一个简单的例子可以是：
#include <gtk/gtk.h>
gboolean on_toggle_button_press_event(GtkWidget *widget, GdkEventButton *event, gpointer user_data) {
if (gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(widget)) == TRUE) {
return TRUE;
}
return FALSE;
}
void on_run_toggle_active(GObject *obj, GParamSpec *pspec, gpointer user_data) {
g_return_if_fail (user_data != NULL);
GtkLabel *label = GTK_LABEL(user_data);
GtkToggleButton *button = GTK_TOGGLE_BUTTON(obj);
if (gtk_toggle_button_get_active(button) == TRUE) {
gtk_label_set_text (label, "Running...");
} else {
gtk_label_set_text (label, "Idle");
}
}
gint main(gint argc, gchar **argv) {
GtkLabel *status;
GtkWindow *window;
GtkBuilder *builder;
GtkToggleButton *run_toggle;
GtkToggleButton *kill_toggle;
gtk_init(&argc, &argv);
builder = gtk_builder_new_from_file("gui.ui");
window = GTK_WINDOW(gtk_builder_get_object(builder, "window1"));
status = GTK_LABEL(gtk_builder_get_object(builder, "status"));
run_toggle = GTK_TOGGLE_BUTTON(gtk_builder_get_object(builder, "toggle"));
kill_toggle = GTK_TOGGLE_BUTTON(gtk_builder_get_object(builder, "kill"));
g_object_bind_property (G_OBJECT(run_toggle), "active", G_OBJECT(kill_toggle), "active", G_BINDING_INVERT_BOOLEAN);
g_object_bind_property (G_OBJECT(kill_toggle), "active", G_OBJECT(run_toggle), "active", G_BINDING_INVERT_BOOLEAN);
g_signal_connect(G_OBJECT(run_toggle), "button-press-event", G_CALLBACK(on_toggle_button_press_event), NULL);
g_signal_connect(G_OBJECT(kill_toggle), "button-press-event", G_CALLBACK(on_toggle_button_press_event), NULL);
g_signal_connect(G_OBJECT(run_toggle), "notify::active", G_CALLBACK(on_run_toggle_active), status);
g_signal_connect(G_OBJECT(window), "destroy", G_CALLBACK(gtk_main_quit), NULL);
gtk_widget_show_all(GTK_WIDGET(window));
gtk_main();
return 0;
}
为简化起见，我使用 glade (gui.ui) 概述了用户界面：
<?xml version="1.0" encoding="UTF-8"?>
<!-- Generated with glade 3.20.2 -->
<interface>
<requires lib="gtk+" version="3.18"/>
<object class="GtkWindow" id="window1">
<property name="can_focus">False</property>
<child>
<object class="GtkGrid">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="halign">center</property>
<property name="valign">center</property>
<property name="row_spacing">20</property>
<child>
<object class="GtkLabel" id="status">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="label" translatable="yes">Idle</property>
</object>
<packing>
<property name="left_attach">0</property>
<property name="top_attach">1</property>
<property name="width">2</property>
</packing>
</child>
<child>
<object class="GtkBox">
<property name="visible">True</property>
<property name="can_focus">False</property>
<child>
<object class="GtkToggleButton" id="toggle">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="focus_on_click">False</property>
<property name="receives_default">True</property>
<child>
<object class="GtkBox">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="spacing">3</property>
<child>
<object class="GtkImage">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="icon_name">media-playback-start-symbolic</property>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">True</property>
<property name="position">0</property>
</packing>
</child>
<child>
<object class="GtkLabel" id="label1">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="label" translatable="yes">Run</property>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">True</property>
<property name="position">1</property>
</packing>
</child>
</object>
</child>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">True</property>
<property name="position">0</property>
</packing>
</child>
<child>
<object class="GtkToggleButton" id="kill">
<property name="visible">True</property>
<property name="can_focus">True</property>
<property name="receives_default">True</property>
<property name="active">True</property>
<child>
<object class="GtkBox">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="spacing">3</property>
<child>
<object class="GtkImage">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="icon_name">user-trash-symbolic</property>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">True</property>
<property name="position">0</property>
</packing>
</child>
<child>
<object class="GtkLabel" id="label2">
<property name="visible">True</property>
<property name="can_focus">False</property>
<property name="label" translatable="yes">Kill</property>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">True</property>
<property name="position">1</property>
</packing>
</child>
</object>
</child>
</object>
<packing>
<property name="expand">False</property>
<property name="fill">True</property>
<property name="position">1</property>
</packing>
</child>
<style>
<class name="linked"/>
</style>
</object>
<packing>
<property name="left_attach">0</property>
<property name="top_attach">0</property>
<property name="width">2</property>
</packing>
</child>
</object>
</child>
<child type="titlebar">
<placeholder/>
</child>
</object>
<object class="GtkSizeGroup">
<widgets>
<widget name="label1"/>
<widget name="label2"/>
</widgets>
</object>
</interface>
编译：
gcc -o main main.c `pkg-config --cflags --libs gtk+-3.0`
输出应该是这样的：
切换按钮是互斥的，在激活时按下它们不会有任何视觉效果。
PS：假设没有键盘处理，否则我们必须处理这些信号并采取相应的行动。
【讨论】：