Java Event handling 4 (Focus, keyboard

FocusEvent Focus Event

Interface

Addfocuslistener (Focuslistener Listener)

There are two ways of

 Public void Focusgains (focusevent e)  Public void focuslost (focusevent e)

Test code

classMywinextendsjframe{JTextField text1,text2;    JButton Button1,button2;        Mywin () {init (); SetVisible (true);    Setdefaultcloseoperation (Jframe.exit_on_close); }    voidinit () {Text1=NewJTextField (8);        Add (Text1); SetLayout (NewFlowLayout ()); Focuspolice FocusPolice1=NewFocuspolice ();        Text1.addfocuslistener (FocusPolice1); Add (NewJButton ("click")); }}classFocuspoliceImplementsfocuslistener{ Public voidfocusgained (focusevent e) {System.out.print ("11"); }     Public voidFocuslost (focusevent e) {System.out.print ("22"); }}

Keyboard events

Addkeylistener (KeyEvent e)

KeyListener has three interfaces

void keypressed (keyevent e)// Press the keyboard void keyreleased (keyevent e)//  Release keyboard void keytyped (keyevent e)// set of Actions

There are two methods of KeyEvent

getKeyCode ()// return a key code value, but do not know I always return 0Getkeychar ()// return the character on the key

A code that automatically jumps the text box

classMywinextendsjframe{JTextField text[]=NewJtextfield[3];    JButton Button1,button2;        Mywin () {init (); SetVisible (true);    Setdefaultcloseoperation (Jframe.exit_on_close); }    voidinit () {setlayout (NewFlowLayout ()); Keypolice KeyPolice1=NewKeypolice ();  for(inti=0;i<3;i++) {Text[i]=NewJTextField (8);            Text[i].addkeylistener (KeyPolice1);            Text[i].addfocuslistener (KeyPolice1);        Add (Text[i]); } text[1].requestfocusinwindow (); Add (button1=NewJButton ("click")); }}classKeypoliceImplementskeylistener,focuslistener{ Public voidkeypressed (KeyEvent e) {} Public voidkeyreleased (KeyEvent e) {} Public voidkeytyped (KeyEvent e) {JTextField Text1=(JTextField) E.getsource (); if(Text1.gettext (). Length () >=6)//There's 7 of them to jump.Text1.transferfocus ();//Jump Function    }     Public voidfocusgained (focusevent e) {//JTextField text= (JTextField) E.getsource ();//It doesn't seem to work .//text.settext (null);    }     Public voidFocuslost (FocusEvent e) {}}

Java Event handling 4 (Focus, keyboard