StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
text
Body
copied!<p>Here second <code>JTextField</code> is acting the way you want it to. Try your hands on this code example : </p> <pre><code>import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.text.*; public class TextFieldExample { private JTextField tfield1; private JTextField tfield2; private JLabel label; private JButton button; private FocusListener tfieldListener = new FocusListener() { @Override public void focusGained(FocusEvent fe) { } @Override public void focusLost(FocusEvent fe) { System.out.println("I am LOST"); String num1 = tfield1.getText().trim(); String num2 = tfield2.getText().trim(); if (num1 == null || num1.equals("")) num1 = "0"; if (num2 == null || num2.equals("")) num2 = "0"; label.setText(Integer.toString(Integer.parseInt(num1) + Integer.parseInt(num2))); } }; private void displayGUI() { JFrame frame = new JFrame("Text Field Focus Example"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JPanel contentPane = new JPanel(); contentPane.setLayout(new FlowLayout(FlowLayout.LEFT, 5, 5)); tfield1 = new JTextField(10); tfield2 = new JTextField(10); tfield2.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent ae) { button.requestFocusInWindow(); } }); tfield1.addFocusListener(tfieldListener); tfield2.addFocusListener(tfieldListener); ((AbstractDocument)tfield1.getDocument()).setDocumentFilter(new MyDocumentFilter()); ((AbstractDocument)tfield2.getDocument()).setDocumentFilter(new MyDocumentFilter()); label = new JLabel("SUM IS"); button = new JButton("USELESS"); contentPane.add(tfield1); contentPane.add(tfield2); contentPane.add(label); contentPane.add(button); frame.setContentPane(contentPane); frame.pack(); frame.setLocationByPlatform(true); frame.setVisible(true); } class MyDocumentFilter extends DocumentFilter { @Override public void insertString(FilterBypass fb, int offset , String text , AttributeSet aset) { try { super.insertString(fb, offset, text.replaceAll("\\D++", ""), aset); } catch(BadLocationException ble) { ble.printStackTrace(); } } @Override public void replace(FilterBypass fb, int offset, int len , String text , AttributeSet aset) { try { super.replace(fb, offset, len, text.replaceAll("\\D++", ""), aset); } catch(BadLocationException ble) { ble.printStackTrace(); } } } public static void main(String... args) { SwingUtilities.invokeLater(new Runnable() { public void run() { new TextFieldExample().displayGUI(); } }); } } </code></pre>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload