java语言程序设计-基础篇--第八版--英文课件(第16章).pptVIP

Handling Mouse Events * Example: Moving Message Using Mouse Objective: Create a program to display a message in a panel. You can use the mouse to move the message. The message moves as the mouse drags and is always displayed at the mouse point. * MoveMessageDemo Run Handling Keyboard Events keyPressed(KeyEvent e) Called when a key is pressed. keyReleased(KeyEvent e) Called when a key is released. keyTyped(KeyEvent e) Called when a key is pressed and thenreleased. * To process a keyboard event, use the following handlers in the KeyListener interface: The KeyEvent Class Methods: getKeyChar() method getKeyCode() method Keys: Home VK_HOME End VK_END Page Up VK_PGUP Page Down VK_PGDN etc... * The KeyEvent Class, cont. * Example: Keyboard Events Demo Objective: Display a user-input character. The user can also move the character up, down, left, and right using the arrow keys. * KeyEventDemo Run The Timer Class Some non-GUI components can fire events. The javax.swing.Timer class is a source component that fires an ActionEvent at a predefined rate. * The Timer class can be used to control animations. For example, you can use it to display a moving message. AnimationDemo Run Clock Animation In Chapter 14, you drew a StillClock to show the current time. The clock does not tick after it is displayed. What can you do to make the clock display a new current time every second? The key to making the clock tick is to repaint it every second with a new current time. You can use a timer to control how to repaint the clock. * ClockAnimation Run * * * * Liang, Introduction to Java Programming, Eighth Edition, (c) 2011 Pearson Education, Inc. All rights reserved. 0132130807 Liang, Introduction to Java Programming, Eighth Edition, (c) 2011 Pearson Education, Inc. All rights reserved. 0132130807 Liang, Introduction to Java Programming, Eighth Edition, (c) 2011 Pearson Education, Inc. All rights reserved. 0132130807 Chapter 16 Event-Driven Programming * Motivations