How to Scroll to a Selected Item in a Java JList?

How can I programmatically scroll to a selected item in a JList in Java?

DefaultListModel<String> model = new DefaultListModel<>();
// Add items to model
model.addElement("Item 1");
model.addElement("Item 2");
model.addElement("Item 3");

JList<String> jList = new JList<>(model);

// Select item at index 1 (second item)
jList.setSelectedIndex(1);
jList.ensureIndexIsVisible(jList.getSelectedIndex()); // Scroll to selected item

In Java, when working with a `JList`, it is often necessary to scroll to a selected item for better user experience. This can be easily achieved using the `ensureIndexIsVisible(int index)` method of the `JList` class. This method ensures that the specified index is visible by scrolling, if necessary.

DefaultListModel<String> model = new DefaultListModel<>();
// Populating the model with sample items
model.addElement("Item 1");
model.addElement("Item 2");
model.addElement("Item 3");

JList<String> jList = new JList<>(model);

// Selecting the item at index 1
jList.setSelectedIndex(1);
// Ensuring the selected index is visible
jList.ensureIndexIsVisible(jList.getSelectedIndex()); // Scroll to the selected item

Causes

• The user interface may not display the selected item if it is not within the visible area of the list.
• Users may find it difficult to navigate through long lists without automatically scrolling to their selected items.

Solutions

• Use `setSelectedIndex(int index)` to select the desired item in the JList.
• Call `ensureIndexIsVisible(int index)` right after setting the selected item to ensure it is in view when selected.

Mistake: Not calling ensureIndexIsVisible after setting the selected index.

Solution: Always call ensureIndexIsVisible after changing the selected index to ensure the selected item is visible.

Mistake: Attempting to scroll without the JList having focus.

Solution: Make sure the JList has focus and is visible in the GUI before making selection and scrolling calls.