Hi, this adds a simple demonstration for the NavigationFilter class to the Swing Activity board. It installs a NavigationFilter that restricts cursor movement to be word-wise. It works well on the RI but currently causes an endless recursive loop on Classpath. Seems like I have overlooked something. :)
I will file a PR and fix that tomorrow.
Here is the ChangeLog:
2006-04-18 Robert Schuster <[EMAIL PROTECTED]>
* examples/gnu/classpath/examples/swing/NavigationFilterDemo.java:
New file.
* examples/gnu/classpath/examples/swing/Demo.java:
(mkMenuBar): Added NavigationFilter demo.
cya
Robert
Index: examples/gnu/classpath/examples/swing/Demo.java
===================================================================
RCS file: /cvsroot/classpath/classpath/examples/gnu/classpath/examples/swing/Demo.java,v
retrieving revision 1.44
diff -u -r1.44 Demo.java
--- examples/gnu/classpath/examples/swing/Demo.java 18 Apr 2006 19:37:48 -0000 1.44
+++ examples/gnu/classpath/examples/swing/Demo.java 18 Apr 2006 20:50:54 -0000
@@ -153,6 +153,9 @@
examples.add(new JMenuItem(new PopupAction("DocumentFilter",
DocumentFilterDemo.createDemoFactory())));
+
+ examples.add(new JMenuItem(new PopupAction("NavigationFilter",
+ NavigationFilterDemo.createDemoFactory())));
final JMenuItem vmMenu;
Index: examples/gnu/classpath/examples/swing/NavigationFilterDemo.java
===================================================================
RCS file: examples/gnu/classpath/examples/swing/NavigationFilterDemo.java
diff -N examples/gnu/classpath/examples/swing/NavigationFilterDemo.java
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ examples/gnu/classpath/examples/swing/NavigationFilterDemo.java 18 Apr 2006 20:50:54 -0000
@@ -0,0 +1,206 @@
+/* NavigationFilterDemo.java -- An example for the NavigationFilter class.
+ Copyright (C) 2006 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath examples.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+*/
+
+
+package gnu.classpath.examples.swing;
+
+import java.awt.BorderLayout;
+import java.awt.Point;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+import javax.swing.JButton;
+import javax.swing.JComponent;
+import javax.swing.JFrame;
+import javax.swing.JPanel;
+import javax.swing.JTextArea;
+import javax.swing.SwingConstants;
+import javax.swing.SwingUtilities;
+import javax.swing.text.BadLocationException;
+import javax.swing.text.JTextComponent;
+import javax.swing.text.NavigationFilter;
+import javax.swing.text.Position;
+import javax.swing.text.Utilities;
+
+/**
+ * A demonstration of the <code>javax.swing.text.NavigationFilter</code> class.
+ *
+ * <p>It shows a NavigationFilter which lets you walk word-wise
+ * through a text.</p>
+ *
+ * @author Robert Schuster
+ */
+public class NavigationFilterDemo
+ extends JPanel
+ implements ActionListener
+{
+
+ JTextArea textArea;
+
+ /**
+ * Creates a new demo instance.
+ */
+ public NavigationFilterDemo()
+ {
+ createContent();
+ // initFrameContent() is only called (from main) when running this app
+ // standalone
+ }
+
+ /**
+ * When the demo is run independently, the frame is displayed, so we should
+ * initialise the content panel (including the demo content and a close
+ * button). But when the demo is run as part of the Swing activity board,
+ * only the demo content panel is used, the frame itself is never displayed,
+ * so we can avoid this step.
+ */
+ void initFrameContent()
+ {
+ JPanel closePanel = new JPanel();
+ JButton closeButton = new JButton("Close");
+ closeButton.setActionCommand("CLOSE");
+ closeButton.addActionListener(this);
+ closePanel.add(closeButton);
+ add(closePanel, BorderLayout.SOUTH);
+ }
+
+ private void createContent()
+ {
+ setLayout(new BorderLayout());
+
+ add(textArea = new JTextArea(10, 20));
+
+ textArea.setWrapStyleWord(true);
+
+ textArea.setLineWrap(true);
+
+ textArea.setNavigationFilter(new WordFilter());
+
+ textArea.setText("GNU Classpath, Essential Libraries for Java, " +
+ "is a GNU project to create free core class " +
+ "libraries for use with virtual machines and " +
+ "compilers for the java programming language.");
+ }
+
+ public void actionPerformed(ActionEvent e)
+ {
+ if (e.getActionCommand().equals("CLOSE"))
+ System.exit(0);
+
+ }
+
+ public static void main(String[] args)
+ {
+ SwingUtilities.invokeLater
+ (new Runnable()
+ {
+ public void run()
+ {
+ NavigationFilterDemo app = new NavigationFilterDemo();
+ app.initFrameContent();
+ JFrame frame = new JFrame("NavigationFilterDemo");
+ frame.getContentPane().add(app);
+ frame.pack();
+ frame.setVisible(true);
+ frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+ }
+ });
+ }
+
+ /**
+ * Returns a DemoFactory that creates a NavigationFilterDemo.
+ *
+ * @return a DemoFactory that creates a NavigationFilterDemo
+ */
+ public static DemoFactory createDemoFactory()
+ {
+ return new DemoFactory()
+ {
+ public JComponent createDemo()
+ {
+ return new NavigationFilterDemo();
+ }
+ };
+ }
+
+ class WordFilter extends NavigationFilter
+ {
+ public int getNextVisualPositionFrom(JTextComponent text,
+ int pos,
+ Position.Bias bias,
+ int direction,
+ Position.Bias[] biasRet)
+ throws BadLocationException
+ {
+ Point pt;
+
+ int newpos = pos;
+ switch (direction)
+ {
+ case SwingConstants.NORTH:
+ // Find out where the caret want to be positioned ideally.
+ pt = text.getCaret().getMagicCaretPosition();
+
+ // Calculate its position above.
+ newpos = Utilities.getPositionAbove(text, pos, pt.x);
+
+ // If we have a valid position, then calculate the next word start
+ // from there.
+ if (newpos != -1)
+ return Utilities.getWordStart(text, newpos);
+ else
+ return pos;
+ case SwingConstants.SOUTH:
+ // Find out where the caret want to be positioned ideally.
+ pt = text.getCaret().getMagicCaretPosition();
+
+ // Calculate its position below.
+ newpos = Utilities.getPositionBelow(text, pos, pt.x);
+
+ // If we have a valid position, then calculate the next word start
+ // from there.
+ if (newpos != -1)
+ return Utilities.getWordStart(text, newpos);
+ else
+ return pos;
+ case SwingConstants.WEST:
+ // Calculate the next word start.
+ newpos = Utilities.getWordStart(text, newpos);;
+
+ // If that means that the caret will not move, return
+ // the start of the previous word.
+ if (newpos != pos)
+ return newpos;
+ else
+ return Utilities.getPreviousWord(text, newpos);
+ case SwingConstants.EAST:
+ // Simply calculate the next word's start offset.
+ return Utilities.getNextWord(text, newpos);
+ default:
+ // Do whatever the super implementation did.
+ return super.getNextVisualPositionFrom(text, pos, bias,
+ direction, biasRet);
+ }
+ }
+
+ }
+
+}
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