19.1 The Swing Text Components

Despite all the complexity and power Swing's text components provide, it's still pretty simple to do most things. Figure 19-1 shows each of the six Swing text components, plus an extra JTextArea (to show a different wrapping style) and an extra JEditorPane (to show a different EditorKit).

// TextComponentSampler.java // import javax.swing.*; import javax.swing.text.*; import javax.swing.border.*; import java.awt.*; public class TextComponentSampler extends JFrame {   public static String word = "portmeiron";   public static String markup =     "Questions are <font size='+1' color='blue'>a burden</font> to others,\n" +     "answers <font size='+2' color='red'>a prison</font> for oneself.";   public TextComponentSampler( ) {     super("TextComponentSampler");     JTextField tf = new JTextField(word, 12);     JPasswordField pf = new JPasswordField(word, 12);     MaskFormatter formatter = null;     try { formatter = new MaskFormatter("UUUUU");         } catch (java.text.ParseException ex) { }     JFormattedTextField ftf = new JFormattedTextField(formatter);     ftf.setColumns(12);     ftf.setValue(word);     JTextArea ta1 = new JTextArea(markup);     JScrollPane scroll1 = new JScrollPane(ta1);     JTextArea ta2 = new JTextArea(markup);     ta2.setLineWrap(true);     ta2.setWrapStyleWord(true);     JScrollPane scroll2 = new JScrollPane(ta2);     JTextPane tp = new JTextPane( );     tp.setText(markup);     // Create an AttributeSet with which to change color and font.     SimpleAttributeSet attrs = new SimpleAttributeSet( );     StyleConstants.setForeground(attrs, Color.blue);     StyleConstants.setFontFamily(attrs, "Serif");     // Apply the AttributeSet to a few blocks of text.     StyledDocument sdoc = tp.getStyledDocument( );     sdoc.setCharacterAttributes(14, 29, attrs, false);     sdoc.setCharacterAttributes(51, 7, attrs, false);     sdoc.setCharacterAttributes(78, 28, attrs, false);     sdoc.setCharacterAttributes(114, 7, attrs, false);     JScrollPane scroll3 = new JScrollPane(tp);     JEditorPane ep1 = new JEditorPane("text/plain", markup);     JScrollPane scroll4 = new JScrollPane(ep1);     JEditorPane ep2 = new JEditorPane("text/html", markup);     JScrollPane scroll5 = new JScrollPane(ep2);     // Done creating text components; now lay them out and make them pretty.     JPanel panel_tf = new JPanel( );     JPanel panel_pf = new JPanel( );     JPanel panel_ftf = new JPanel( );     panel_tf.add(tf);     panel_pf.add(pf);     panel_ftf.add(ftf);     panel_tf.setBorder(new TitledBorder("JTextField"));     panel_pf.setBorder(new TitledBorder("JPasswordField"));     panel_ftf.setBorder(new TitledBorder("JFormattedTextField"));     scroll1.setBorder(new TitledBorder("JTextArea (line wrap off)"));     scroll2.setBorder(new TitledBorder("JTextArea (line wrap on)"));     scroll3.setBorder(new TitledBorder("JTextPane"));     scroll4.setBorder(new TitledBorder("JEditorPane (text/plain)"));     scroll5.setBorder(new TitledBorder("JEditorPane (text/html)"));     JPanel pan = new JPanel(new FlowLayout(FlowLayout.LEFT));     pan.add(panel_tf);     pan.add(panel_pf);     pan.add(panel_ftf);     Container contentPane = getContentPane( );     contentPane.setLayout(new GridLayout(2, 3, 8, 8));     contentPane.add(pan);     contentPane.add(scroll1);     contentPane.add(scroll2);     contentPane.add(scroll3);     contentPane.add(scroll4);     contentPane.add(scroll5);   }   public static void main(String args[]) {     JFrame frame = new TextComponentSampler( );     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);     frame.setSize(600, 450);     frame.setVisible(true);   } } 

Unlike java.awt.TextArea, the multiline Swing text components lack built-in scrollbars. If you want scrollbars and you almost always do you must create your own JScrollPane. Fortunately, this is easy to do. Just replace add(myTextComp) with add(new JScrollPane(myTextComp)). In most L&Fs, scrollbars do not appear unless they are needed.