Java key Event KeyEvent

Key events can use the keyboard to control and perform some actions, or to get input from the keyboard, as long as the press, releasing a key or tapping on a component, triggers a key event. The KeyEvent object describes the characteristics of the event (press, release, or tap a key) and the corresponding value. Java provides keylistener interface for handling key events.

      When a key is pressed, the keypressed processor is called, and when a key is released, the keyreleased processor is called, and the keytyped processor is called when a uniform encoding is entered. If this key is not a unified code (such as function keys, modifier keys, action keys and Control keys)       Each keystroke event has a related key character and key code, which is returned by the Getkeychar () and getKeyCode () methods in KeyEvent respectively       getkeychar ():  char           Returns the key-related characters in this event      G Etkeycode ():  int             Returns the integer key associated with the key in this event  keypressed (e:keyevent)   &nbs P     called after pressing a key on the source component keyreleased (e:keyevent)       Releasing a key on the source component after it is called keytyped (e:keyevent)   & nbsp       Press a key on the source component and then release the key after being called   Key constants  vk_home         HOME key       &N Bsp                  vk_control                   Control key vk_end            end               &NBS P             Vk_shift                      SHIFT key Vk_pgup         &NB Sp;page up                       vk_back_space     &NBSP ;       BACKSPACE vk_pgdn          page down key             &NB Sp     Vk_caps_lock               case lock key vk_up               UP ARROW                            vk_num_l Ock                 keypad LOCK key
Vk_down         down ARROW                       &NBSP ;    vk_enter                       Enter Vk_left           LEFT arrow                           &NBSP ; vk_undefined                 unknown key vk_right           RIGHT ARROW &nbs P                         VK_F1--VK_F12       &NB Sp        F1-f12vk_escape       ESC               & nbsp              VK_0--vk_9                    0---9vk_tab             TAB               &NBSP ;             VK_A--vk_z                    A---- Z getkeycode () returns the value defined in the table Getkeychar () returns the input character  

1 Importjava.awt.*;2 Importjava.awt.event.*;3 Importjavax.swing.*;4  5  Public classKeyeventdemoextendsjframe{6         PrivateKeyboardpanel Keyboardpanel =NewKeyboardpanel ();7        8          PublicKeyeventdemo () {9 Add (keyboardpanel);Ten                OneKeyboardpanel.setfocusable (true); A                -        } -         the          Public Static voidMain (string[] args) { -Keyeventdemo frame =NewKeyeventdemo (); -Frame.settitle ("Keyeventdemo"); -Frame.setsize (300,300); +Frame.setlocationrelativeto (NULL); - frame.setdefaultcloseoperation (JFrame. Exit_on_close); +Frame.setvisible (true); A                at        } -         -         Static classKeyboardpanelextendsjpanel{ -                Private intx = 100; -                Private inty = 100; -                Private CharKeyChar = ' A ' ; in                -                 PublicKeyboardpanel () { toAddkeylistener (NewKeyadapter () { +                              Public voidkeypressed (KeyEvent e) { -                                    Switch(E.getkeycode ()) { the                                     CaseKeyevent.vk_down:y + = 10; Break; *                                     CaseKeyevent.vk_up:y-= 10; Break; $                                     CaseKeyevent.vk_left:x-= 10; Break;Panax Notoginseng                                     CaseKeyevent.vk_right:x + = 10; Break; -                                    default: KeyChar =E.getkeychar (); the                                   } +                                    A repaint (); the                            } +                      }); -               } $                $                protected voidpaintcomponent (Graphics g) { -                       Super. paintcomponent (g); -                       theG.setfont (NewFont ("Timesroman", font.plain,24)); - g.drawstring (String. ValueOf (KeyChar), x, y);Wuyi               } the        } -}

Java key Event KeyEvent