Realtime printing of what's typed

Question

public class NewJFrame3 extends javax.swing.JFrame {

/**
 * Creates new form NewJFrame3
 */
public NewJFrame3() {
    initComponents();
}

/**
 * This method is called          


        

Answer 1

Try something like this :

// Listen for changes in the text
textField.getDocument().addDocumentListener(new DocumentListener() {
  public void changedUpdate(DocumentEvent e) {
    warn();
  }
  public void removeUpdate(DocumentEvent e) {
    warn();
  }
  public void insertUpdate(DocumentEvent e) {
    warn();
  }

  public void warn() {
     if (Integer.parseInt(textField.getText())<=0){
       JOptionPane.showMessageDialog(null,
          "Error: Please enter number bigger than 0", "Error Massage",
          JOptionPane.ERROR_MESSAGE);
     }
  }
});

Answer 2

You will need to attach a DocumentListener to your textfield. See this tutorial for more information.