Add DocumentListener to validate multiple JTextFields

Question

Code given below does real time validation for one JTextField. While entering some values to txt1 enables the save button and removing values reset the save button to disable. I use Netbeans as IDE.

My Swing application has few JTextFields. What I want to do is, enable Save button after checking multiple JTextFields for validity. If any of the text fields is empty, btnSave must be disabled.

Can someone assist me to expand this program to validate multiple JTextFields?

public NewJFrame() {
        initComponents();
        btnSave.setEnabled(false);

        txt1.getDocument().addDocumentListener(new DocumentListener() {
              @Override
              public void changedUpdate(DocumentEvent e) {

              }

              @Override
              public void removeUpdate(DocumentEvent e) {
                    validate(e);
              }

              @Override
              public void insertUpdate(DocumentEvent e) {
                    validate(e);
              }

              public void validate(DocumentEvent e) {
                    String currText = "";
                    try {
                          Document doc = (Document) e.getDocument();
                          currText = doc.getText(0, doc.getLength());
                    } catch (BadLocationException e1) {
                          e1.printStackTrace();
                    }
                    if (currText.isEmpty()) {
                          Runnable doRun = new Runnable() {
                                @Override
                                public void run() {
                                      isValidFromTextField1 = false;
                                      validFormatterLimit();

                                }
                          };
                          SwingUtilities.invokeLater(doRun);
                    } else {
                          Runnable doRun = new Runnable() {
                                @Override
                                public void run() {
                                      isValidFromTextField1 = true;
                                      validFormatterLimit();

                                }
                          };
                          SwingUtilities.invokeLater(doRun);
                    }
              }
        });


        txt2.getDocument().addDocumentListener(new DocumentListener() {
              @Override
              public void changedUpdate(DocumentEvent e) {

              }

              @Override
              public void removeUpdate(DocumentEvent e) {
                    validate(e);
              }

              @Override
              public void insertUpdate(DocumentEvent e) {
                    validate(e);
              }

              public void validate(DocumentEvent e) {
                    String currText = "";
                    try {
                          Document doc = (Document) e.getDocument();
                          currText = doc.getText(0, doc.getLength());
                    } catch (BadLocationException e1) {
                          e1.printStackTrace();
                    }
                    if (currText.isEmpty()) {
                          Runnable doRun = new Runnable() {
                                @Override
                                public void run() {
                                      isValidFromTextField2 = false;
                                      validFormatterLimit();

                                }
                          };
                          SwingUtilities.invokeLater(doRun);
                    } else {
                          Runnable doRun = new Runnable() {
                                @Override
                                public void run() {
                                      isValidFromTextField2 = true;
                                      validFormatterLimit();

                                }
                          };
                          SwingUtilities.invokeLater(doRun);
                    }
              }
        });





  }

  public void validFormatterLimit() {

        if (isValidFromTextField1 == true && isValidFromTextField2 == true) {
              btnSave.setEnabled(true);
        } else {
              btnSave.setEnabled(false);
        }

  }

Answer 1

• have to split validations

• each of events should be called from every JComponents

• very simple example with required steps

delayed (3,5 sec) by Swing Timer

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.font.TextAttribute;
import java.math.*;
import java.text.*;
import java.util.Map;
import java.util.Vector;
import javax.swing.*;
import javax.swing.JFormattedTextField.AbstractFormatter;
import javax.swing.JFormattedTextField.AbstractFormatterFactory;
import javax.swing.event.*;
import javax.swing.text.InternationalFormatter;

public class FormatterLimit {

    private JFrame frame = new JFrame("AbstractTextField Test");
    private Map attributes = (new Font("Serif", Font.BOLD, 16)).getAttributes();
    private JFormattedTextField textField1 = new JFormattedTextField(new Float(710.01));
    private JFormattedTextField textField2 = new JFormattedTextField(new Float(150.01));
    private Vector<Boolean> comboBoxItems = new Vector<Boolean>();
    private JComboBox box = new JComboBox(comboBoxItems);
    private JButton btn = new JButton("Validations !!!");
    private Boolean isValidFromTextField1 = true;
    private Boolean isValidFromTextField2 = true;
    private Boolean isValidFromBox = true;
    private javax.swing.Timer timer = null;

    public FormatterLimit() {
        attributes.put(TextAttribute.STRIKETHROUGH, TextAttribute.STRIKETHROUGH_ON);
        textField1.setFormatterFactory(new AbstractFormatterFactory() {
            @Override
            public AbstractFormatter getFormatter(JFormattedTextField tf) {
                NumberFormat format = DecimalFormat.getInstance();
                format.setMinimumFractionDigits(2);
                format.setMaximumFractionDigits(2);
                format.setRoundingMode(RoundingMode.HALF_UP);
                InternationalFormatter formatter = new InternationalFormatter(format);
                formatter.setAllowsInvalid(false);
                formatter.setMinimum(0.0);
                formatter.setMaximum(1000.00);
                return formatter;
            }
        });
        textField1.getDocument().addDocumentListener(new DocumentListener() {
            @Override
            public void changedUpdate(DocumentEvent documentEvent) {
                printIt(documentEvent);
            }

            @Override
            public void insertUpdate(DocumentEvent documentEvent) {
                printIt(documentEvent);
            }

            @Override
            public void removeUpdate(DocumentEvent documentEvent) {
                printIt(documentEvent);
            }

            private void printIt(DocumentEvent documentEvent) {
                DocumentEvent.EventType type = documentEvent.getType();
                double t1a1 = (((Number) textField1.getValue()).doubleValue());
                if (t1a1 < 500) {
                    Runnable doRun = new Runnable() {
                        @Override
                        public void run() {
                            isValidFromTextField1 = false;
                            validFormatterLimit();
                            textField1.setFont(new Font(attributes));
                            textField1.setForeground(Color.red);
                        }
                    };
                    SwingUtilities.invokeLater(doRun);
                } else {
                    Runnable doRun = new Runnable() {
                        @Override
                        public void run() {
                            isValidFromTextField1 = true;
                            validFormatterLimit();
                            textField1.setFont(new Font("Serif", Font.BOLD, 16));
                            textField1.setForeground(Color.black);
                        }
                    };
                    SwingUtilities.invokeLater(doRun);
                }
            }
        });
        textField2.setFormatterFactory(new AbstractFormatterFactory() {
            @Override
            public AbstractFormatter getFormatter(JFormattedTextField tf) {
                NumberFormat format = DecimalFormat.getInstance();
                format.setMinimumFractionDigits(2);
                format.setMaximumFractionDigits(2);
                format.setRoundingMode(RoundingMode.HALF_UP);
                InternationalFormatter formatter = new InternationalFormatter(format);
                formatter.setAllowsInvalid(false);
                //formatter.setMinimum(0.0);
                //formatter.setMaximum(1000.00);
                return formatter;
            }
        });
        textField2.getDocument().addDocumentListener(new DocumentListener() {
            @Override
            public void changedUpdate(DocumentEvent documentEvent) {
                printIt(documentEvent);
            }

            @Override
            public void insertUpdate(DocumentEvent documentEvent) {
                printIt(documentEvent);
            }

            @Override
            public void removeUpdate(DocumentEvent documentEvent) {
                printIt(documentEvent);
            }

            private void printIt(DocumentEvent documentEvent) {
                DocumentEvent.EventType type = documentEvent.getType();
                double t1a1 = (((Number) textField2.getValue()).doubleValue());
                if (t1a1 > 1000) {
                    Runnable doRun = new Runnable() {
                        @Override
                        public void run() {
                            isValidFromTextField2 = false;
                            validFormatterLimit();
                            textField2.setFont(new Font(attributes));
                            textField2.setForeground(Color.red);
                        }
                    };
                    SwingUtilities.invokeLater(doRun);
                } else {
                    Runnable doRun = new Runnable() {
                        @Override
                        public void run() {
                            isValidFromTextField2 = true;
                            validFormatterLimit();
                            textField2.setFont(new Font("Serif", Font.BOLD, 16));
                            textField2.setForeground(Color.black);
                        }
                    };
                    SwingUtilities.invokeLater(doRun);
                }
            }
        });
        comboBoxItems.add(Boolean.TRUE);
        comboBoxItems.add(Boolean.FALSE);
        box = new JComboBox(comboBoxItems);
        box.addItemListener(new ItemListener() {
            @Override
            public void itemStateChanged(ItemEvent e) {
                if (e.getStateChange() == ItemEvent.SELECTED) {
                    if (e.getSource() == box) {
                        if (box.getSelectedItem() == (Boolean) true) {
                            isValidFromBox = true;
                            validFormatterLimit();
                        } else {
                            isValidFromBox = false;
                            validFormatterLimit();
                        }
                    }
                }
            }
        });
        frame.setLayout(new GridLayout(5, 0, 5, 5));
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(textField1);
        frame.add(textField2);
        frame.add(box, BorderLayout.SOUTH);
        frame.add(new JLabel());
        frame.add(btn);
        frame.setVisible(true);
        frame.pack();
        start();
    }

    private void start() {
        timer = new javax.swing.Timer(3500, updateCol());
        timer.setRepeats(false);
        timer.start();
    }

    public Action updateCol() {
        return new AbstractAction("text load action") {
            private static final long serialVersionUID = 1L;

            @Override
            public void actionPerformed(ActionEvent e) {
                textField1.setValue(300);
                textField2.setValue(8000);
                if (box.getSelectedItem() == (Boolean) false) {
                    box.setSelectedItem((Boolean) true);
                } else {
                    box.setSelectedItem((Boolean) false);
                }
            }
        };
    }

    public void validFormatterLimit(/*Boolean isValidFromTextField1, 
             * Boolean isValidFromTextField2 , Boolean isValidFromBox*/) {
        if (isValidFromTextField1) {
            if (isValidFromTextField2) {
                if (isValidFromBox) {
                    btn.setEnabled(true);
                } else {
                    btn.setEnabled(false);
                }
            } else {
                btn.setEnabled(false);
            }
        } else {
            btn.setEnabled(false);
        }
    }


    public static void main(String args[]) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                FormatterLimit comboBoxModel = new FormatterLimit();
            }
        });
    }
}