How to Bind a Shortcut Key to a JButton in Java

In Java, you can assign shortcut keys to buttons (e.g., clicking the "Delete" key triggers a button click) by implementing an Action, binding it to a KeyStroke, then associating the Action with the button.

To do so, follow these steps:

1. Create an Action class that defines the behavior when the shortcut key is pressed, typically using an anonymous inner class.
2. Register the Action with the button using a call to button.addActionListener().

3. Map the shortcut key to the Action using InputMap and ActionMap as shown:

   • getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW) retrieves the input map for keyboard events when the button panel has focus.
   • put(KeyStroke, Object) associates the desired key with the Action.
   • getActionMap().put(Object, Action) associates the Action with the mapped key.

Here's an example code snippet that implements these steps:

public class CalculatorPanel extends JPanel {
    // ... (code removed for brevity)

    for (int i = 0; i 
This code defines an Action that inserts the keystroke value into a text field when triggered. When the buttons are created, they are mapped to their respective keys on both the main and numeric keypads. As a result, pressing the corresponding keys (e.g., "1" or "NUMPAD 1") activates the associated button.