Java - Scroll to specific text inside JTextArea
This should work:
textArea.setCaretPosition(posOfTextToScroll);
You can get the posOfTextToScroll
by the Document
model. Read about it, in the Javadoc.
This is a VERY basic example. This basically walks the document to find the position of the word within the document and ensures that the text is moved to the viewable area.
It also highlights the match
public class MoveToText {
public static void main(String[] args) {
new MoveToText();
}
public MoveToText() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new FindTextPane());
frame.setSize(400, 400);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class FindTextPane extends JPanel {
private JTextField findField;
private JButton findButton;
private JTextArea textArea;
private int pos = 0;
public FindTextPane() {
setLayout(new BorderLayout());
findButton = new JButton("Next");
findField = new JTextField("Java", 10);
textArea = new JTextArea();
textArea.setWrapStyleWord(true);
textArea.setLineWrap(true);
Reader reader = null;
try {
reader = new FileReader(new File("Java.txt"));
textArea.read(reader, null);
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
reader.close();
} catch (Exception e) {
}
}
JPanel header = new JPanel(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
gbc.anchor = GridBagConstraints.WEST;
header.add(findField, gbc);
gbc.gridx++;
header.add(findButton, gbc);
add(header, BorderLayout.NORTH);
add(new JScrollPane(textArea));
findButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// Get the text to find...convert it to lower case for eaiser comparision
String find = findField.getText().toLowerCase();
// Focus the text area, otherwise the highlighting won't show up
textArea.requestFocusInWindow();
// Make sure we have a valid search term
if (find != null && find.length() > 0) {
Document document = textArea.getDocument();
int findLength = find.length();
try {
boolean found = false;
// Rest the search position if we're at the end of the document
if (pos + findLength > document.getLength()) {
pos = 0;
}
// While we haven't reached the end...
// "<=" Correction
while (pos + findLength <= document.getLength()) {
// Extract the text from teh docuemnt
String match = document.getText(pos, findLength).toLowerCase();
// Check to see if it matches or request
if (match.equals(find)) {
found = true;
break;
}
pos++;
}
// Did we find something...
if (found) {
// Get the rectangle of the where the text would be visible...
Rectangle viewRect = textArea.modelToView(pos);
// Scroll to make the rectangle visible
textArea.scrollRectToVisible(viewRect);
// Highlight the text
textArea.setCaretPosition(pos + findLength);
textArea.moveCaretPosition(pos);
// Move the search position beyond the current match
pos += findLength;
}
} catch (Exception exp) {
exp.printStackTrace();
}
}
}
});
}
}
}