mirror of https://github.com/fltk/fltk
89 lines
4.1 KiB
HTML
89 lines
4.1 KiB
HTML
<HTML>
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<HEAD>
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<TITLE>Fl_Choice</TITLE>
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</HEAD>
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<BODY>
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<!-- NEW PAGE -->
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<H2><A name=Fl_Choice>class Fl_Choice</A></H2>
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<HR>
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<H3>Class Hierarchy</H3>
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<UL>
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<PRE>
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<A href=Fl_Menu_.html#Fl_Menu_>Fl_Menu_</A>
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+----<B>Fl_Choice</B>
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</PRE>
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</UL>
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<H3>Include Files</H3>
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<UL>
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<PRE>
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#include <FL/Fl_Choice.H>
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</PRE>
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</UL>
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<H3>Description</H3>
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This is a button that when pushed pops up a menu (or hierarchy of
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menus) defined by an array of <A href=Fl_Menu_Item.html#Fl_Menu_Item><TT>
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Fl_Menu_Item</TT></A> objects. Motif calls this an OptionButton.
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<P>The only difference between this and a <A href=Fl_Menu_Button.html#Fl_Menu_Button>
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<TT>Fl_Menu_Button</TT></A> is that the name of the most recent chosen
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menu item is displayed inside the box, while the label is displayed
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outside the box. However, since the use of this is most often to
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control a single variable rather than do individual callbacks, some of
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the <TT>Fl_Menu_Button</TT> methods are redescribed here in those
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terms. </P>
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<P>When the user picks an item off the menu the <TT>value()</TT>
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is set to that item and then the item's callback is done with
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the menu_button as the <TT>Fl_Widget*</TT> argument. If the
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item does not have a callback the menu_button's callback is done
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instead. </P>
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<P>All three mouse buttons pop up the menu. The Forms behavior of the
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first two buttons to increment/decrement the choice is not implemented.
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This could be added with a subclass, however. </P>
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<P>The menu will also pop up in response to shortcuts indicated by
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putting a '&' character in the <TT>label()</TT>. See <A href=Fl_Button.html#Fl_Button>
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<TT>Fl_Button</TT></A> for a description of this. </P>
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<P>Typing the <TT>shortcut()</TT> of any of the items will do exactly
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the same as when you pick the item with the mouse. The '&' character in
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item names are only looked at when the menu is popped up, however. </P>
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<P ALIGN=CENTER><IMG src="choice.gif" ALT="Fl_Choice widget."></P>
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<H3>Methods</H3>
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<UL>
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<LI><A href=#Fl_Choice.Fl_Choice>Fl_Choice</A></LI>
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<LI><A href=#Fl_Choice.~Fl_Choice>~Fl_Choice</A></LI>
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<LI><A href=#Fl_Choice.clear_changed>clear_changed</A></LI>
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<LI><A href=#Fl_Choice.changed>changed</A></LI>
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<LI><A href=#Fl_Choice.down_box>down_box</A></LI>
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<LI><A href=#Fl_Choice.set_changed>set_changed</A></LI>
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<LI><A href=#Fl_Choice.value>value</A></LI>
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</UL>
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<H4><A name=Fl_Choice.Fl_Choice>Fl_Choice::Fl_Choice(int x, int y, int
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w, int h, const char *label = 0)</A></H4>
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Creates a new <TT>Fl_Choice</TT> widget using the given position,
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size, and label string. The default boxtype is <TT>FL_UP_BOX</TT>.
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<P>The constructor sets <TT>menu()</TT> to <TT>NULL</TT>. See <A href=Fl_Menu_.html#Fl_Menu_>
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<TT>Fl_Menu_</TT></A> for the methods to set or change the menu. </P>
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<H4><A name=Fl_Choice.~Fl_Choice>virtual Fl_Choice::~Fl_Choice()</A></H4>
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The destructor removes the <TT>Fl_Choice</TT> widget and all of its
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menu items.
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<H4><A name=Fl_Choice.value>int Fl_Choice::value() const
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<BR> int Fl_Choice::value(int)
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<BR> int Fl_Choice::value(const Fl_Menu *)</A></H4>
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The value is the index into the <TT>Fl_Menu</TT> array of the last
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item chosen by the user. It is zero initially. You can set it as an
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integer, or set it with a pointer to a menu item. The set routines
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return non-zero if the new value is different than the old one.
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Changing it causes a <TT>redraw()</TT>.
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<H4><A name=Fl_Choice.changed>int Fl_Widget::changed() const</A></H4>
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This value is true if the user picks a different value. <I>It is
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turned off by <TT>value()</TT> and just before doing a callback (the
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callback can turn it back on if desired).</I>
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<H4><A name=Fl_Choice.set_changed>void Fl_Widget::set_changed()</A></H4>
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This method sets the <TT>changed()</TT> flag.
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<H4><A name=Fl_Choice.clear_changed>void Fl_Widget::clear_changed()</A></H4>
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This method clears the <TT>changed()</TT> flag.
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<H4><A name=Fl_Choice.down_box>Fl_Boxtype Fl_Choice::down_box() const
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<BR> void Fl_Choice::down_box(Fl_Boxtype b)</A></H4>
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The first form gets the current down box, which is used when the menu
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is popped up. The default down box type is <TT>FL_DOWN_BOX</TT> The
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second form sets the current down box type to <TT>b</TT>. </BODY></HTML>
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