CODEWITHSUNDEEP
javaswingbuttonlistenerjtextfield
user3648179
user3648179

Reputation: 35

Set enable button if text field is fill

I have few text fields. How to enable button if user filled all text fields and disable if user delete something? I'm using Swing.

Upvotes: 1

Views: 8273

Answers (2)

René Link
René Link

Reputation: 51333

Since swing is based on MVC you can use the model objects and listen to changes.

public class Main {

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        Container contentPane = frame.getContentPane();
        contentPane.setLayout(new BoxLayout(contentPane, BoxLayout.PAGE_AXIS));

        JTextField textField1 = new JTextField(30);
        JTextField textField2 = new JTextField(30);
        JTextField textField3 = new JTextField(30);
        JButton jButton = new JButton("Button");

        ButtonModel model = jButton.getModel();
        Document document1 = textField1.getDocument();
        Document document2 = textField2.getDocument();
        Document document3 = textField3.getDocument();

        ButtonEnablement buttonEnablement = new ButtonEnablement(model);
        buttonEnablement.addDocument(document1);
        buttonEnablement.addDocument(document2);
        buttonEnablement.addDocument(document3);

        contentPane.add(textField1);
        contentPane.add(textField2);
        contentPane.add(textField3);
        contentPane.add(jButton);

        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

}

Whenever one Document changes the ButtonEnablement will take a look at all Documents and enable the ButtonModel.

public class ButtonEnablement implements DocumentListener {

        private ButtonModel buttonModel;
        private List<Document> documents = new ArrayList<Document>();

        public ButtonEnablement(ButtonModel buttonModel) {
            this.buttonModel = buttonModel;
        }

        public void addDocument(Document document) {
            document.addDocumentListener(this);
            this.documents.add(document);
            documentChanged();
        }

        public void documentChanged() {
            boolean buttonEnabled = false;
            for (Document document : documents) {
                if (document.getLength() > 0) {
                    buttonEnabled = true;
                    break;
                }
            }
            buttonModel.setEnabled(buttonEnabled);
        }

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

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

        @Override
        public void changedUpdate(DocumentEvent e) {
            documentChanged();
        }
    }

The advantage of using a ButtonModel and Document instead of a JButton and JTextField is that you can easily change the concrete implementations and you don't have to worry on how your ui components get updated, because they get updated automatically when their model changes.

Upvotes: 1

Roy Iacob
Roy Iacob

Reputation: 412

You could set an event listener to see when textfields change. Then disable the button if an fields are empty:

field1.addKeyListener(new KeyAdapter() {
        public void keyReleased(KeyEvent e) { //watch for key strokes
            if(field1.getText().length() == 0 || field2.getText().length() == 0)
                button.setEnabled(false);
            else
            {
                Button.setEnabled(true);
            }
        }
 });

The strategy here is:

  1. Watch for any key strokes on your fields. You need to duplicate this event listener for field 2 (and any other fields you might have).
  2. Default your button to disabled since the fields are empty
  3. If the fields ever have zero characters, disable the button. Otherwise, enable it.

Upvotes: 0

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