Updating background color of JTextField automatically

Question

well i made a JTextField and i want it's background to be red when there are no characters in it, and once a character is written to be automatically changed to green.

i tried this code

textField1.setBackground(textField1.getText().equalsIgnoreCase("") ? Color.RED : Color.GREEN);

but it doesn't automatically update it.

thanks

Answer 1

you should add documentListener

textfield.getDocument().addDocumentListener(this);

@Override
    public void insertUpdate(DocumentEvent e) 
    {
        textField1.setBackground(textField1.getText().equalsIgnoreCase("") ? Color.RED : Color.GREEN);
    }

    @Override
    public void removeUpdate(DocumentEvent e) 
    {
        textField1.setBackground(textField1.getText().equalsIgnoreCase("") ? Color.RED : Color.GREEN);
    }

    @Override
    public void changedUpdate(DocumentEvent e) 
    {
        textField1.setBackground(textField1.getText().equalsIgnoreCase("") ? Color.RED : Color.GREEN);    
    }

Also try setting the opaque property of the Textfield.

textField1.setOpaque(True)