空的字符串是””,不带空格
outputStream 在打印时,打印的内容后面不要加\n,否则对方接受和判定不正确
G:\PROJECTION\IC2N\1c2njava>javac Jsubnetframe.java
Jsubnetframe.java:22: Jsubnetframe should be declared abstract; it does not defi
ne valueChanged(javax.swing.event.ListSelectionEvent) in Jsubnetframe
public class Jsubnetframe extends JFrame implements ListSelectionListener {
^
Jsubnetframe.java:68: cannot resolve symbol
symbol : class TableModel
location: class Jsubnetframe
TableModel dataModel = new AbstractTableModel() {
^
Jsubnetframe.java:68: cannot resolve symbol
symbol : class AbstractTableModel
location: class Jsubnetframe
TableModel dataModel = new AbstractTableModel() {
^
Jsubnetframe.java:89: addActionListener(java.awt.event.ActionListener) in javax.
swing.AbstractButton cannot be applied to (Jsubnetframe)
cancelb.addActionListener(this);
^
Note: Jsubnetframe.java uses or overrides a deprecated API.
Note: Recompile with -deprecation for details.
4 errors
原因是没有import javax.swing.table.*;
G:\PROJECTION\IC2N\1c2njava>javac Jhpportframe.java
Jhpportframe.java:27: Jhpportframe should be declared abstract; it does not defi
ne mousePressed(java.awt.event.MouseEvent) in Jhpportframe
public class Jhpportframe extends JFrame implements
^
Note: Jhpportframe.java uses or overrides a deprecated API.
Note: Recompile with -deprecation for details.
1 error
Jhpportframe should be declared abstract; it does not defi 原因是因为在这里必须用MouseListener 的相关方法进行覆盖,也就是说必须加入如下的方法:
public void mousePressed(MouseEvent evt) {//if (audio != null) audio.play();}
public void mouseEntered (MouseEvent me) {}
public void mouseExited (MouseEvent me) {}
public void mouseReleased(MouseEvent me) {}
鼠标左键和右件的事件获取:
public void mousePressed(MouseEvent evt) {
Point point1=evt.getPoint();
int x,y;
int onmask = evt.BUTTON1_DOWN_MASK;//左键的ID号
if ((evt.getModifiersEx() & onmask ) == onmask) // 点击左键时
{
}
else //点击右键时
抽象类,不能进行初始化或者生成实例
hpportimg=new Image(getDocumentBase(),”aaa.gif”);
这句话是错的,因为Image()是抽象类,不能进行初始化或者生成实例.,应该用:
hpportimg=getImage(“adf.gif”);
并且应该注重它不能放在构造函数中,而应该放在INIT()等方法中.
各种动作和事件的处理:
监视键盘的动作,用usertf.addKeyListener(this);它的接口软件包是KeyListener,应该import java.awt.event.*; 必须重载的接口函数是
public void keyPressed(KeyEvent e){}
public void keyReleased(KeyEvent e){}
public void keyTyped(KeyEvent e){}
监视焦点的动作,用usertf.add FocusListener (this);它的接口软件包是FocusListener应该import java.awt.event.*; 必须重载的接口函数是
public void focusLost(FocusEvent e) { }
public void focusGained(FocusEvent e) {}
监视鼠标的动作,用usertf.addMouseListener(this);它的接口软件包是MouseyListener,应该import java.awt.event.*;
//必须增加MouseListener(this) 或component. MouseListener(this)
必须重载的接口函数是
public void mouseClicked(MouseEvent e){ }
public void mousePressed(MouseEvent evt) {}
public void mouseEntered (MouseEvent me) {}
public void mouseExited (MouseEvent me) {}
public void mouseReleased(MouseEvent me) {}
监视鼠标移动的动作,用usertf.addMouseListener(this);它的接口软件包是MouseyMotionListener,应该import java.awt.event.*; 必须重载的接口函数是
public void mouseMoved(MouseEvent e){}
public void mouseDragged(MouseEvent e){ }
以上各种事件必须在组件上增加相应的侦听,如
user.addKeyListener(this);
pass.addKeyListener(this);
user.addFocusListener(this);
pass.addFocusListener(this);
按钮事件的执行在JAVA2中应该用下列函数，无须重载:
public void actionPerformed(ActionEvent ae) {
JButton source=(JButton)ae.getSource();
if(source==okb)
{ slkdfjalskdjflaksdjlfjads;flkjasld;kjfl;kasjdfl;k}
焦点事件:focusLost(),focusGain()
transferFocus()是将焦点传递到下一个组件
requestFocus()是将焦点传递到指定的组件,
if(e.getComponent()==user) user.transferFocus();
else if(e.getComponent()==pass) pass.transferFocus();
else if(e.getComponent()==ok) ok.transferFocus();
经过观察发现,焦点可以在文本框上传递,但是在按钮上好象没法传递.
