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  1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>The QuickNotepadOptionPane Class</title><meta name="generator" content="DocBook XSL Stylesheets V1.65.1"><link rel="home" href="index.html" title="jEdit 4.2 User's Guide"><link rel="up" href="plugin-implement.html" title="Chapter 18. Implementing a Simple Plugin"><link rel="previous" href="plugin-implement-quicknotepadtoolbar.html" title="The QuickNotepadToolBar Class"><link rel="next" href="plugin-implement-docs.html" title="Plugin Documentation"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">The QuickNotepadOptionPane Class</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="plugin-implement-quicknotepadtoolbar.html">Prev</a> </td><th width="60%" align="center">Chapter 18. Implementing a Simple Plugin</th><td width="20%" align="right"> <a accesskey="n" href="plugin-implement-docs.html">Next</a></td></tr></table><hr></div><div class="sect1" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="plugin-implement-options"></a>The QuickNotepadOptionPane Class</h2></div></div><div></div></div><p>
  2  Using the default implementation provided by
  3  <tt class="classname">AbstractOptionPane</tt> reduces the preparation of an
  4  option pane to two principal tasks: writing a
  5  <tt class="function">_init()</tt> method to layout and initialize the pane,
  6  and writing a <tt class="function">_save()</tt> method to commit any settings
  7  changed by user input. If a button on the option pane should trigger
  8  another dialog, such as a <tt class="classname">JFileChooser</tt> or jEdit's
  9  own enhanced <tt class="classname">VFSFileChooserDialog</tt>, the option
 10  pane will also have to implement the
 11  <tt class="classname">ActionListener</tt> interface to display additional
 12  components.
 13</p><p>
 14  The QuickNotepad plugin has only three options to set: the path name of
 15  the file that will store the notepad text, the visibility of the
 16  path name on the tool bar, and the notepad's display font.
 17  Using the shortcut methods of the plugin API, the implementation of
 18  <tt class="function">_init()</tt> looks like this:
 19</p><div class="informalexample"><table border="0" bgcolor="#E0E0E0"><tr><td><pre class="programlisting">public class QuickNotepadOptionPane extends AbstractOptionPane
 20      implements ActionListener
 21{
 22    private JTextField pathName;
 23    private JButton pickPath;
 24    private FontSelector font;
 25
 26    ...
 27
 28    public void _init()
 29    {
 30        showPath = new JCheckBox(jEdit.getProperty(
 31            QuickNotepadPlugin.OPTION_PREFIX
 32            + "show-filepath.title"),
 33        jEdit.getProperty(
 34            QuickNotepadPlugin.OPTION_PREFIX +  "show-filepath")
 35            .equals("true"));
 36        addComponent(showPath);
 37
 38        pathName = new JTextField(jEdit.getProperty(
 39            QuickNotepadPlugin.OPTION_PREFIX
 40            + "filepath"));
 41        JButton pickPath = new JButton(jEdit.getProperty(
 42            QuickNotepadPlugin.OPTION_PREFIX
 43            + "choose-file"));
 44        pickPath.addActionListener(this);
 45
 46        JPanel pathPanel = new JPanel(new BorderLayout(0, 0));
 47        pathPanel.add(pathName, BorderLayout.CENTER);
 48        pathPanel.add(pickPath, BorderLayout.EAST);
 49
 50        addComponent(jEdit.getProperty(
 51            QuickNotepadPlugin.OPTION_PREFIX + "file"),
 52            pathPanel);
 53
 54        font = new FontSelector(makeFont());
 55        addComponent(jEdit.getProperty(
 56            QuickNotepadPlugin.OPTION_PREFIX + "choose-font"),
 57            font);
 58    }
 59
 60    ...
 61
 62}</pre></td></tr></table></div><p>
 63  Here we adopt the vertical arrangement offered by use of the
 64  <tt class="function">addComponent()</tt> method with one embellishment.
 65  We want the first &#8220;<span class="quote">row</span>&#8221; of the option pane to contain
 66  a text field with the current notepad file path and a button that will
 67  trigger a file chooser dialog when pressed.  To place both of them on
 68  the same line (along with an identifying label for the file option),
 69  we create a <tt class="classname">JPanel</tt> to contain both components and
 70  pass the configured panel to <tt class="function">addComponent()</tt>.
 71</p><p>
 72  The <tt class="function">_init()</tt> method uses properties from the plugin's
 73  property file to provide the names of label for the components placed
 74  in the option pane.  It also uses a property whose name begins with
 75  <tt class="function">PROPERTY_PREFIX</tt> as a persistent data item - the
 76  path of the current notepad file.  The elements of the notepad's font
 77  are also extracted from properties using a static method of the option
 78  pane class.
 79</p><p>
 80  The <tt class="function">_save()</tt> method extracts data from the user
 81  input components and
 82  assigns them to the plugin's properties.  The implementation is
 83  straightforward:
 84</p><div class="informalexample"><table border="0" bgcolor="#E0E0E0"><tr><td><pre class="programlisting">public void _save()
 85{
 86    jEdit.setProperty(QuickNotepadPlugin.OPTION_PREFIX
 87        + "filepath", pathName.getText());
 88    Font _font = font.getFont();
 89
 90    jEdit.setProperty(QuickNotepadPlugin.OPTION_PREFIX
 91        + "font", _font.getFamily());
 92    jEdit.setProperty(QuickNotepadPlugin.OPTION_PREFIX
 93        + "fontsize", String.valueOf(_font.getSize()));
 94    jEdit.setProperty(QuickNotepadPlugin.OPTION_PREFIX
 95        + "fontstyle", String.valueOf(_font.getStyle()));
 96    jEdit.setProperty(QuickNotepadPlugin.OPTION_PREFIX
 97        + "show-filepath", String.valueOf(showPath.isSelected()));
 98}</pre></td></tr></table></div><p>
 99  The class has only two other methods, one to display a file chooser
100  dialog in response to user action, and the other
101  to construct a <tt class="classname">Font</tt> object from the plugin's font
102  properties. They do not require discussion here.
103</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="plugin-implement-quicknotepadtoolbar.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="plugin-implement.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="plugin-implement-docs.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">The QuickNotepadToolBar Class </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Plugin Documentation</td></tr></table></div></body></html>