Question

在JAVA中如何做菜单窗体？

Answer 1

package test.combobox;

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.AbstractAction;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JToolBar;
public class TestFrame extends JFrame
{
JTextArea theArea=null;

static final String ComboStr[] = ;

public TestFrame()
{
super("JMenu1");
theArea=new JTextArea();
theArea.setEditable(true);
getContentPane().setLayout(new BorderLayout());
getContentPane().add(new JScrollPane(theArea),BorderLayout.CENTER);
JToolBar theBar=buildToolBar();
getContentPane().add(theBar,BorderLayout.NORTH);
JMenuBar MBar=new JMenuBar();
JMenu mfile=buildFileMenu();
MBar.add(mfile);
setJMenuBar(MBar);
}//end of JMenu1()
public JMenu buildFileMenu()
{
JMenu thefile=new JMenu("文件");
JMenuItem newf=new JMenuItem("新建");
JMenuItem open=new JMenuItem("打开");
JMenuItem close=new JMenuItem("关闭");
JMenuItem exit=new JMenuItem("退出");
thefile.add(newf);
thefile.add(open);
thefile.add(close);
thefile.addSeparator();//分隔线
thefile.add(exit);
return thefile;
}//end of buildFileMenu()
public JToolBar buildToolBar()
{
JToolBar toolBar=new JToolBar();
toolBar.setFloatable(true);//设置JToolBar可否浮动.
//分别构造三个ToolBarAction的类组件,准备将这三个组件设置到JToolBar中.ToolBaarAction类是我们自己编写的inner
// class,这个inner class在程序后半部份,这个类继承AbstractAction,AbstractAction是一个抽象类,实现Action
//interface,而Action interface又继承ActionListener interface又继承AActionListener interface,因此可直接在
//AbstractAction中覆写actionPerformed()方法,处理ActionEvent事件.在JToolBar中有一个add(Action a)方法,只要传入
//Action参数就可以得到一个JButton对象,因此在程序中下面的98,100,102就是以这样的方式来构造出JToolBar上的按钮组
//件.
ToolBarAction tba_new=new ToolBarAction("new",new ImageIcon(
"icons/new24.gif"));
ToolBarAction tba_open=new ToolBarAction("open",new ImageIcon(
"icons/open24.gif"));
ToolBarAction tba_close=new ToolBarAction("close",new ImageIcon(
"icons/close24.gif"));
JButton JB;
JB=toolBar.add(tba_new);//将ToolBarAction组件加入JToolBar中.
JB.setActionCommand("#TooBar_NEW performed!");
JB=toolBar.add(tba_open);//将ToolBarAction组件加入JToolBar中.
JB.setActionCommand("#ToolBar_OPEN performed!");
JB=toolBar.add(tba_close);//将ToolBarAction组件加入JToolBar中.
JB.setActionCommand("#ToolBar_CLOSE performed!");
toolBar.addSeparator();//在JToolBar加上分隔线,如同在JMenu上利用addSeparator()方法加上分隔线一样,不同的是在
//JMenu中分隔线是以灰色直线的样式表现,而在JToolBar中则是以一小段空来表示.
//在JToolBar中加入一个JLabel组件.
JLabel JLfont=new JLabel("Font Type");
toolBar.add(JLfont);

toolBar.addSeparator();
//利用上面定义的ComboStr数建立一个JComboBox组件.
JComboBox jcb = new JComboBox(ComboStr);
//将JComboBar加入事件处理模式.这里是将所选到的组件名称填入JTextArea中.
jcb.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
theArea.append("*Combobox "+((JComboBox)e.getSource()).getSelectedItem()+
" performed!\n");
}});

toolBar.add(jcb);

return toolBar;
}//end of buildToolBar()
class ToolBarAction extends AbstractAction
{
public ToolBarAction(String name,Icon icon)
{
// super(name,icon);

super(name );
}
//对于JToolBar上按钮的事件处理是将组件的ActionCommand返回值字符串加入JTextArea中.
public void actionPerformed(ActionEvent e)
{
try
{
theArea.append(e.getActionCommand()+"\n");
} catch(Exception ex)
{
}
}
}
public static void main(String[] args)
{
JFrame F=new TestFrame();
F.setSize(400,200);
F.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});//end of addWindowListener
F.setVisible(true);
} // end of main
}//end of class JMenu1

Answer 2

窗体JFrame
菜单条JMenuBar
菜单JMenu
子菜单JMenuItem

Answer 3

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.awt.datatransfer.*;

class MyMenuBar extends MenuBar{
public MyMenuBar(Frame parent){
parent.setMenuBar(this);
}
public void addMenus(String [] menus){
for(int i=0;i<menus.length;i++)
add(new Menu(menus[i]));
}
public void addMenuItems(int menuNumber,String[] items){
for(int i=0;i<items.length;i++){
if(items[i]!=null)
getMenu(menuNumber).add(new MenuItem(items[i]));
else getMenu(menuNumber).addSeparator();
}
}
public void addActionListener(ActionListener al){
for(int i=0;i<getMenuCount();i++)
for(int j=0;j<getMenu(i).getItemCount();j++)
getMenu(i).getItem(j).addActionListener(al);
}
}

class MyFile{
private FileDialog fDlg;
public MyFile(Frame parent){
fDlg=new FileDialog(parent,"",FileDialog.LOAD);
}
private String getPath(){
return fDlg.getDirectory()+"\\"+fDlg.getFile();
}
public String getData() throws IOException{
fDlg.setTitle("打开");
fDlg.setMode(FileDialog.LOAD);
fDlg.setVisible(true);
BufferedReader br=new BufferedReader(new FileReader(getPath()));
StringBuffer sb=new StringBuffer();
String aline;
while((aline=br.readLine())!=null)
sb.append(aline+'\n');
br.close();
return sb.toString();
}
public void setData(String data) throws IOException{
fDlg.setTitle("保存");
fDlg.setMode(FileDialog.SAVE);
fDlg.setVisible(true);
BufferedWriter bw=new BufferedWriter(new FileWriter(getPath()));
bw.write(data);
bw.close();
}
}

class MyClipboard{
private Clipboard cb;
public MyClipboard(){
cb=Toolkit.getDefaultToolkit().getSystemClipboard();
}
public void setData(String data){
cb.setContents(new StringSelection(data),null);
}
public String getData(){
Transferable content=cb.getContents(null);
try{
return (String) content.getTransferData(DataFlavor.stringFlavor);
//DataFlavor.stringFlavor会将剪贴板中的字符串转换成Unicode码形式的String对象。
//DataFlavor类是与存储在剪贴板上的数据的形式有关的类。
}catch(Exception ue){}
return null;
}
}

class MyFindDialog extends Dialog implements ActionListener{
private Label lFind=new Label("查找字符串");
private Label lReplace=new Label("替换字符串");
private TextField tFind=new TextField(10);
private TextField tReplace=new TextField(10);
private Button bFind=new Button("查找");
private Button bReplace=new Button("替换");
private TextArea ta;
public MyFindDialog(Frame owner,TextArea ta){
super(owner,"查找",false);
this.ta=ta;
setLayout(null);
lFind.setBounds(10,30,80,20);
lReplace.setBounds(10,70,80,20);
tFind.setBounds(90,30,90,20);
tReplace.setBounds(90,70,90,20);
bFind.setBounds(190,30,80,20);
bReplace.setBounds(190,70,80,20);
add(lFind);
add(tFind);
add(bFind);
add(lReplace);
add(tReplace);
add(bReplace);
setResizable(false);
bFind.addActionListener(this);
bReplace.addActionListener(this);
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
MyFindDialog.this.dispose();
}
});
}//构造函数结束
public void showFind(){
setTitle("查找");
setSize(280,60);
setVisible(true);
}
public void showReplace(){
setTitle("查找替换");
setSize(280,110);
setVisible(true);
}
private void find(){
String text=ta.getText();
String str=tFind.getText();
int end=text.length();
int len=str.length();
int start=ta.getSelectionEnd();
if(start==end) start=0;
for(;start<=end-len;start++){
if(text.substring(start,start+len).equals(str)){
ta.setSelectionStart(start);
ta.setSelectionEnd(start+len);
return;
}
}
//若找不到待查字符串，则将光标置于末尾
ta.setSelectionStart(end);
ta.setSelectionEnd(end);
}

public Button getBFind() {
return bFind;
}
private void replace(){
String str=tReplace.getText();
if(ta.getSelectedText().equals(tFind.getText()))
ta.replaceRange(str,ta.getSelectionStart(),ta.getSelectionEnd());
else find();
}

public void actionPerformed(ActionEvent e) {
if(e.getSource()==bFind)
find();
else if(e.getSource()==bReplace)
replace();
}
}

public class MyMemo extends Frame implements ActionListener{
private TextArea editor=new TextArea(); //可编辑的TextArea
private MyFile mf=new MyFile(this);//MyFile对象
private MyClipboard cb=new MyClipboard();
private MyFindDialog findDlg=new MyFindDialog(this,editor);

public MyMemo(String title){ //构造函数
super(title);
MyMenuBar mb=new MyMenuBar(this);
//添加需要的菜单及菜单项
mb.addMenus(new String[]{"文件","编辑","查找","帮助"});
mb.addMenuItems(0,new String[]{"新建","打开","保存",null,"全选"});
mb.addMenuItems(1,new String[]{"剪贴","复制","粘贴","清除",null,"全选"});
mb.addMenuItems(2,new String[]{"查找",null,"查找替换"});
mb.addMenuItems(3,new String[]{"我的记事本信息"});

add(editor); //为菜单项注册动作时间监听器
mb.addActionListener(this);

addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
MyMemo.this.dispose();
}
}); //分号不能忘了
} //构造函数完

public void actionPerformed(ActionEvent e){
String selected=e.getActionCommand(); //获取菜单项标题
if(selected.equals("新建"))
editor.setText("");
else if(selected.equals("打开")){
try{
editor.setText(mf.getData());
}catch(IOException ie){}
}
else if(selected.equals("保存")){
try{
mf.setData(editor.getText());
}catch(IOException ie){}
}
else if(selected.equals("退出")){
dispose();
}
else if(selected.equals("剪贴")){
//将选中的字符串复制到剪贴板中并清除字符串
cb.setData(editor.getSelectedText());
editor.replaceRange("",editor.getSelectionStart(),editor.getSelectionEnd());
}
else if(selected.equals("复制")){
cb.setData(editor.getSelectedText());
}
else if(selected.equals("粘贴")){
String str=cb.getData();
editor.replaceRange(str,editor.getSelectionStart(),editor.getSelectionEnd());
//粘贴在光标位置
}
else if(selected.equals("清除")){
editor.replaceRange("",editor.getSelectionStart(),editor.getSelectionEnd());
}
else if(selected.equals("全选")){
editor.setSelectionStart(0);
editor.setSelectionEnd(editor.getText().length());
}
else if(selected.equals("查找")){
findDlg.showFind();
}
else if(selected.equals("查找替换")){
findDlg.showReplace();
}
}

public static void main(String[] args){
MyMemo memo=new MyMemo("记事本");
memo.setSize(650,450);
memo.setVisible(true);
}
}