Java tutorial
/* Core SWING Advanced Programming By Kim Topley ISBN: 0 13 083292 8 Publisher: Prentice Hall */ import java.awt.Color; import java.awt.Cursor; import java.awt.GridBagConstraints; import java.awt.GridBagLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import java.beans.PropertyChangeEvent; import java.beans.PropertyChangeListener; import java.io.BufferedOutputStream; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.io.Writer; import java.net.URL; import javax.swing.JButton; import javax.swing.JEditorPane; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JOptionPane; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTextField; import javax.swing.UIManager; import javax.swing.text.BadLocationException; import javax.swing.text.Document; public class EditorPaneExample6 extends JFrame { public EditorPaneExample6() { super("JEditorPane Example 6"); pane = new JEditorPane(); pane.setEditable(false); // Start read-only getContentPane().add(new JScrollPane(pane), "Center"); // Build the panel of controls JPanel panel = new JPanel(); panel.setLayout(new GridBagLayout()); GridBagConstraints c = new GridBagConstraints(); c.gridwidth = 1; c.gridheight = 1; c.anchor = GridBagConstraints.EAST; c.fill = GridBagConstraints.NONE; c.weightx = 0.0; c.weighty = 0.0; JLabel urlLabel = new JLabel("File name: ", JLabel.RIGHT); panel.add(urlLabel, c); JLabel loadingLabel = new JLabel("State: ", JLabel.RIGHT); c.gridy = 1; panel.add(loadingLabel, c); JLabel typeLabel = new JLabel("Type: ", JLabel.RIGHT); c.gridy = 2; panel.add(typeLabel, c); c.gridx = 1; c.gridy = 0; c.gridwidth = 1; c.weightx = 1.0; c.fill = GridBagConstraints.HORIZONTAL; textField = new JTextField(32); panel.add(textField, c); loadingState = new JLabel(spaces, JLabel.LEFT); loadingState.setForeground(Color.black); c.gridy = 1; c.gridwidth = 2; panel.add(loadingState, c); loadedType = new JLabel(spaces, JLabel.LEFT); loadedType.setForeground(Color.black); c.gridy = 2; panel.add(loadedType, c); // Add a "Save" button saveButton = new JButton("Save"); saveButton.setEnabled(false); c.gridwidth = 1; c.gridx = 2; c.gridy = 0; c.weightx = 0.0; panel.add(saveButton, c); getContentPane().add(panel, "South"); // Change page based on text field textField.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent evt) { String fileName = textField.getText().trim(); file = new File(fileName); absolutePath = file.getAbsolutePath(); String url = "file:///" + absolutePath; try { // Check if the new page and the old // page are the same. URL newURL = new URL(url); URL loadedURL = pane.getPage(); if (loadedURL != null && loadedURL.sameFile(newURL)) { return; } // Try to display the page textField.setEnabled(false); // Disable input textField.paintImmediately(0, 0, textField.getSize().width, textField.getSize().height); saveButton.setEnabled(false); saveButton.paintImmediately(0, 0, saveButton.getSize().width, saveButton.getSize().height); setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR)); // Busy cursor loadingState.setText("Loading..."); loadingState.paintImmediately(0, 0, loadingState.getSize().width, loadingState.getSize().height); loadedType.setText(""); loadedType.paintImmediately(0, 0, loadedType.getSize().width, loadedType.getSize().height); pane.setEditable(false); pane.setPage(url); loadedType.setText(pane.getContentType()); } catch (Exception e) { JOptionPane.showMessageDialog(pane, new String[] { "Unable to open file", url }, "File Open Error", JOptionPane.ERROR_MESSAGE); loadingState.setText("Failed"); textField.setEnabled(true); setCursor(Cursor.getDefaultCursor()); } } }); // Listen for page load to complete pane.addPropertyChangeListener(new PropertyChangeListener() { public void propertyChange(PropertyChangeEvent evt) { if (evt.getPropertyName().equals("page")) { loadingState.setText("Page loaded."); textField.setEnabled(true); // Allow entry of new file name textField.requestFocus(); setCursor(Cursor.getDefaultCursor()); // Allow editing and saving if appropriate pane.setEditable(file.canWrite()); saveButton.setEnabled(file.canWrite()); } } }); // Save button saveButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent evt) { try { String type = pane.getContentType(); OutputStream os = new BufferedOutputStream(new FileOutputStream(file + ".save")); pane.setEditable(false); textField.setEnabled(false); saveButton.setEnabled(false); setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR)); Document doc = pane.getDocument(); int length = doc.getLength(); if (type.endsWith("/rtf")) { // Saving RTF - use the OutputStream try { pane.getEditorKit().write(os, doc, 0, length); os.close(); } catch (BadLocationException ex) { } } else { // Not RTF - use a Writer. Writer w = new OutputStreamWriter(os); pane.write(w); w.close(); } } catch (IOException e) { JOptionPane.showMessageDialog(pane, new String[] { "Unable to save file", file.getAbsolutePath(), }, "File Save Error", JOptionPane.ERROR_MESSAGE); } pane.setEditable(file.canWrite()); textField.setEnabled(true); saveButton.setEnabled(file.canWrite()); setCursor(Cursor.getDefaultCursor()); } }); } public static void main(String[] args) { try { UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); } catch (Exception evt) { } JFrame f = new EditorPaneExample6(); f.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent evt) { System.exit(0); } }); f.setSize(500, 400); f.setVisible(true); } private static final String spaces = " "; private File file; private String absolutePath; private JEditorPane pane; private JTextField textField; private JLabel loadingState; private JLabel loadedType; private JButton saveButton; }