How to Dynamically Update a JLabel with ArrayList Data Using a Swing Timer?

Updating JLabel Dynamically in Java

When working with GUIs, it's essential to update labels dynamically to display real-time data or user input. This question explores how to update a JLabel at regular intervals within a Java program.

Question:

How to use Swing Timer to update JLabel at regular intervals to display the data stored in ArrayList?

Answer:

1. Use of Swing Timer

Swing Timer is used to perform regular tasks in the Java SWING library class. To update a JLabel every once in a while, we use a Swing Timer and set up an ActionListener to handle the update task.

2. ActionListener implementation

ActionListener implementation acts as a callback for Swing Timer. The ActionListener executes its actionPerformed method every time the timer fires. In this method, we access the words in the ArrayList and update the text of the JLabel.

3. Starting and stopping Timer

The timer is started by the start() method and stopped by the stop() method. The timer stops when it has finished traversing the ArrayList or when certain conditions are encountered.

Sample code:

private void updateJLabel() {
    final Timer timer = new Timer(500, null);
    ActionListener listener = new ActionListener() {
        private Iterator<word> iterator = words.iterator();
        @Override 
        public void actionPerformed(ActionEvent e) {
            if (iterator.hasNext()) {
                _textField.setText(iterator.next().getName());
            }
            else {
                timer.stop();
            }
        }
    };
    timer.addActionListener(listener);
    timer.start();
    
}</word>

Note:

We assume that _textField is the JLabel to be updated.

Following this step, you can dynamically update a JLabel in Java and display data at a specified interval.

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