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<META name=vsisbn content="1558515682"><META name=vstitle content="Java Digital Signal Processing"><META name=vsauthor content="Douglas A. Lyon"><META name=vsimprint content="M&T Books"><META name=vspublisher content="IDG Books Worldwide, Inc."><META name=vspubdate content="11/01/97"><META name=vscategory content="Web and Software Development: Programming, Scripting, and Markup Languages: Java"><TITLE>Java Digital Signal Processing:The Graphical User Interface</TITLE>
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<P><BR></P>
<H4 ALIGN="LEFT"><A NAME="Heading16"></A><FONT COLOR="#000077">Class Usage</FONT></H4>
<P>The <I>MenuItem</I> class is a subclass of <I>MenuComponent</I> and is used to store a string item that represents a menu choice. Assume that the following variables are predefined:</P>
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<PRE>
MenuItem ifft_mi = new MenuItem(“[2] IFFT”);
String label;
boolean on;
</PRE>
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<P>To get and set the string contained in the <I>MenuItem</I> instance, use the following:</P>
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<PRE>
str = ifft_mi.getLabel();
ifft_mi.setLabel(label);
</PRE>
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<P>To get and set the enabling on the <I>MenuItem</I> instance:</P>
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<PRE>
on = ifft_mi.isEnabled();
ifft_mi.enable(); // always enables
ifft_mi.enable(on); // conditionally enables
ifft_mi.disable(); // always disables
</PRE>
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<P>To obtain <I>“label=”</I> + <I>ifft_mi.getLabel()</I>, use this:</P>
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<PRE>
label = ifft_mi.paramString();
</PRE>
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<BLOCKQUOTE>
<P><FONT SIZE="-1"><HR>The <I>MenuItem</I> class has a special “-” label that is used as a separator. An example of the separator’s appearance in the menu is shown in Figure 3.5.<HR></FONT>
</BLOCKQUOTE>
<P><A NAME="Fig5"></A><A HREF="javascript:displayWindow('images/03-05.jpg',146,177 )"><IMG SRC="images/03-05t.jpg"></A>
<BR><A HREF="javascript:displayWindow('images/03-05.jpg',146,177)"><FONT COLOR="#000077"><B>Figure 3.5</B></FONT></A> The separator is shown between <I>SendMail</I> and <I>ls</I>.
</P>
<H3><A NAME="Heading17"></A><FONT COLOR="#000077">The Event Class</FONT></H3>
<P>The <I>Event</I> class is a reference data type that is a direct descendent of the <I>java.lang.Object</I> class. The <I>handleEvent</I> method is invoked with an instance of the <I>Event</I> class whenever user input is detected. <I>Components</I> are said to <I>post</I> events.</P>
<H4 ALIGN="LEFT"><A NAME="Heading18"></A><FONT COLOR="#000077">Class Summary</FONT></H4>
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<PRE>
public class Event {
public static final int SHIFT_MASK
public static final int CTRL_MASK
public static final int META_MASK
public static final int ALT_MASK
public static final int HOME
public static final int END
public static final int PGUP
public static final int PGDN
public static final int UP
public static final int DOWN
public static final int LEFT
public static final int RIGHT
public static final int F1
public static final int F2
public static final int F3
public static final int F4
public static final int F5
public static final int F6
public static final int F7
public static final int F8
public static final int F9
public static final int F10
public static final int F11
public static final int F12
public static final int WINDOW_DESTROY
public static final int WINDOW_EXPOSE
public static final int WINDOW_ICONIFY
public static final int WINDOW_DEICONIFY
public static final int WINDOW_MOVED
public static final int KEY_PRESS
public static final int KEY_RELEASE
public static final int KEY_ACTION
public static final int KEY_ACTION_RELEASE
public static final int MOUSE_DOWN
public static final int MOUSE_UP
public static final int MOUSE_MOVE
public static final int MOUSE_ENTER
public static final int MOUSE_EXIT
public static final int MOUSE_DRAG
public static final int SCROLL_LINE_UP
public static final int SCROLL_LINE_DOWN
public static final int SCROLL_PAGE_UP
public static final int SCROLL_PAGE_DOWN
public static final int SCROLL_ABSOLUTE
public static final int LIST_SELECT
public static final int LIST_DESELECT
public static final int ACTION_EVENT
public static final int LOAD_FILE
public static final int SAVE_FILE
public static final int GOT_FOCUS
public static final int LOST_FOCUS
public Object target;
public long when;
public int id;
public int x;
public int y;
public int key;
public int modifiers;
public int clickCount;
public Object arg;
public Event evt;
/* Methods */
public Event(Object target, long when, int id, int x, int y, int key,
int modifiers, Object arg)
public Event(Object target, long when, int id, int x, int y, int key,
int modifiers)
public Event(Object target, int id, Object arg)
public void translate(int x, int y)
public boolean shiftDown()
public boolean controlDown()
public boolean metaDown()
protected String paramString()
public String toString()
}
</PRE>
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