Value Change Listener to JTextField

Question

I want the message box to appear immediately after the user changes the value in the textfield. Currently, I need to hit the enter key to get the message box to pop out. Is

Answer 1

I know this relates to a really old problem, however, it caused me some problems too. As kleopatra responded in a comment above, I solved the problem with a JFormattedTextField. However, the solution requires a bit more work, but is neater.

The JFormattedTextField doesn't by default trigger a property change after every text changes in the field. The default constructor of JFormattedTextField does not create a formatter.

However, to do what the OP suggested, you need to use a formatter which will invoke the commitEdit() method after each valid edit of the field. The commitEdit() method is what triggers the property change from what I can see and without the formatter, this is triggered by default on a focus change or when the enter key is pressed.

See http://docs.oracle.com/javase/tutorial/uiswing/components/formattedtextfield.html#value for more details.

Create a default formatter (DefaultFormatter) object to be passed to the JFormattedTextField either via its constructor or a setter method. One method of the default formatter is setCommitsOnValidEdit(boolean commit), which sets the formatter to trigger the commitEdit() method every time the text is changed. This can then be picked up using a PropertyChangeListener and the propertyChange() method.