Key events occur when a key is pressed on the keyboard. Any component can generate these events, and a class must implement KeyListener interface to support them. The following example shows how to use key events in Swing. Hi, everyone, please explain displaying JPanel, ON button click in the same Frame i've displayed a new JFrame with respect to button click but not JPanel.
The following Java code shows an example program that implements the KeyListener interface. When executed, the Java code will show a very simple Swing Graphical User Interface.
Background
The GUI is made up of a JFrame which contains two JTextAreas. The first, feedbackTextJTextArea, is placed inside a JScrollPane and is used to display text generated by the KeyListener events. The JScrollPane allows the user to see all the lines of text generated by the KeyListener events.
The second is the inputText JTextArea. This JTextArea has the focus and will generate KeyListener events as the user types into it. By default, the inputArea JTextArea will have the focus when the JFrame appears.
The KeyListener interface could have been implemented as a separate class, or extending the JFrame, but in this instance using an anonymous inner class makes the most sense.
The keyPressed method is called when a user presses down on a key and the keyReleased method is called when a key is released. The keyTyped method is called when a character key is typed into the inputText JTextArea.
Generate Key Code
Java Code Listing
