用Java创建一个简单的文本编辑器

Question

如何创建记事本等文本编辑器？使用Java的GUI元素，使用“新文件”，“打开文件”，“保存文件”，“格式化文本”等功能。

Answer 1

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;

public class Texteditor extends JFrame implements ActionListener
{
            MenuBar mbar;
            Menu file,edit,format,font,font1,font2;
            MenuItem item1,item2,item3,item4;
            MenuItem item5,item6,item7,item8,item9,item10;
            MenuItem fname1,fname2,fname3,fname4;
            MenuItem fstyle1,fstyle2,fstyle3,fstyle4;
            MenuItem fsize1,fsize2,fsize3,fsize4;

JPanel mainpanel;
TextArea text;

Font f;
String months[]={
"Jan","Feb","Mar","Apr",
"May","Jun","Jul","Aug",
"Sep","Oct","Nov","Dec"};

GregorianCalendar gcalendar;


String command=" ";
String str=" ";

String str1=" ",str2=" ",str3=" ";
String str4=" ";

String str6=" ";
String str7=" ",str8=" ",str9=" ";

int len1;

int i=0;
int pos1;
int len;

public Texteditor(String str)
{

super(str);

mainpanel=new JPanel();
mainpanel=(JPanel)getContentPane();
mainpanel.setLayout(new FlowLayout());


mbar=new MenuBar();
setMenuBar(mbar);

file=new Menu("File");
edit=new Menu("Edit");
format=new Menu("Format");
font=new Menu("Font");
font1=new Menu("Font Style");
font2=new Menu("Size");

file.add(item1=new MenuItem("New..."));
file.add(item2=new MenuItem("Open"));
file.add(item3=new MenuItem("Save As..."));
file.add(item4=new MenuItem("Exit"));
mbar.add(file);


edit.add(item5=new MenuItem("Cut (Ctrl+X)"));
edit.add(item6=new MenuItem("Copy (Ctrl+C)"));
edit.add(item7=new MenuItem("Paste (Ctrl+V)"));
edit.add(item8=new MenuItem("Delete"));
edit.add(item10=new MenuItem("Select All (Ctrl+A)"));
edit.add(item9=new MenuItem("Time/Date"));
mbar.add(edit);

format.add(font);
format.add(font1);
format.add(font2);

font.add(fname1=new MenuItem("Courier"));
font.add(fname2=new MenuItem("Sans Serif"));
font.add(fname3=new MenuItem("Monospaced"));
font.add(fname4=new MenuItem("Symbol"));

font1.add(fstyle1=new MenuItem("Regular"));
font1.add(fstyle2=new MenuItem("Bold"));
font1.add(fstyle3=new MenuItem("Italic"));
font1.add(fstyle4=new MenuItem("Bold Italic"));

font2.add(fsize1=new MenuItem("12"));
font2.add(fsize2=new MenuItem("14"));
font2.add(fsize3=new MenuItem("18"));
font2.add(fsize4=new MenuItem("20"));

mbar.add(format);



item1.addActionListener(this);
item2.addActionListener(this);
item3.addActionListener(this);
item4.addActionListener(this);
item5.addActionListener(this);
item6.addActionListener(this);
item7.addActionListener(this);
item8.addActionListener(this);
item9.addActionListener(this);
item10.addActionListener(this);
fname1.addActionListener(this);
fname2.addActionListener(this);
fname3.addActionListener(this);
fname4.addActionListener(this);
fstyle1.addActionListener(this);
fstyle2.addActionListener(this);
fstyle3.addActionListener(this);
fstyle4.addActionListener(this);
fsize1.addActionListener(this);
fsize2.addActionListener(this);
fsize3.addActionListener(this);
fsize4.addActionListener(this);


text=new TextArea(26,60);
mainpanel.add(text);

f=new Font("Monotype Corsiva",Font.PLAIN,15);
text.setFont(f);
}




public void actionPerformed(ActionEvent ae)
{


command=(String)ae.getActionCommand();

if(command.equals("New..."))
{
dispose();
Texteditor note1 = new Texteditor("Untitled-Notepad");
note1.setSize(500,500);
note1.setVisible(true);
}

try
{

if(command.equals("Open"))
{

str4=" ";
FileDialog dialog=new FileDialog(this,"Open");
dialog.setVisible(true);

str1=dialog.getDirectory();
str2=dialog.getFile();
str3=str1+str2;
File f=new File(str3);
FileInputStream fobj=new FileInputStream(f);
len=(int)f.length();
for(int j=0;j<len;j++)
{
char str5=(char)fobj.read();
str4=str4 + str5;

}

text.setText(str4);

}
}
catch(IOException e)
{}


try
{

if(command.equals("Save As..."))
{
FileDialog dialog1=new FileDialog(this,"Save As",FileDialog.SAVE);
dialog1.setVisible(true);

str7=dialog1.getDirectory();
str8=dialog1.getFile();
str9=str7+str8;


str6=text.getText();
len1=str6.length();
byte buf[]=str6.getBytes();

File f1=new File(str9);
FileOutputStream fobj1=new FileOutputStream(f1);
for(int k=0;k<len1;k++)
{
fobj1.write(buf[k]);
}
fobj1.close();
}

this.setTitle(str8);

}
catch(IOException e){}



if(command.equals("Exit"))
{
System.exit(0);
}

if(command.equals("Cut (Ctrl+X)"))
{
str=text.getSelectedText();
i=text.getText().indexOf(str);
text.replaceRange(" ",i,i+str.length());
}

if(command.equals("Copy (Ctrl+C)"))
{
str=text.getSelectedText();
}

if(command.equals("Paste (Ctrl+V)"))
{
pos1=text.getCaretPosition();
text.insert(str,pos1);
}
if(command.equals("Delete"))
{
String msg=text.getSelectedText();
i=text.getText().indexOf(msg);
text.replaceRange(" ",i,i+msg.length());
}
if(command.equals("Time/Date"))
{
gcalendar=new GregorianCalendar();
String h=String.valueOf(gcalendar.get(Calendar.HOUR));
String m=String.valueOf(gcalendar.get(Calendar.MINUTE));
String s=String.valueOf(gcalendar.get(Calendar.SECOND));
String date=String.valueOf(gcalendar.get(Calendar.DATE));
String mon=months[gcalendar.get(Calendar.MONTH)];
String year=String.valueOf(gcalendar.get(Calendar.YEAR));
String hms="Time"+" - "+h+":"+m+":"+s+" Date"+" - "+date+" "+mon+" "+year;
int loc=text.getCaretPosition();
text.insert(hms,loc);
}
if(command.equals("Courier"))
{

String fontName=f.getName();
String fontFamily=f.getFamily();
int fontSize=f.getSize();
int fontStyle=f.getStyle();

f=new Font("Courier",fontStyle,fontSize);
text.setFont(f);
}
if(command.equals("Sans Serif"))
{
String fontName=f.getName();
String fontFamily=f.getFamily();
int fontSize=f.getSize();
int fontStyle=f.getStyle();

f=new Font("Sans Serif",fontStyle,fontSize);
text.setFont(f);
}
if(command.equals("Monospaced"))
{
String fontName=f.getName();
String fontFamily=f.getFamily();
int fontSize=f.getSize();
int fontStyle=f.getStyle();

f=new Font("Monospaced",fontStyle,fontSize);
text.setFont(f);
}

if(command.equals("Symbol"))
{
String fontName=f.getName();
String fontFamily=f.getFamily();
int fontSize=f.getSize();
int fontStyle=f.getStyle();

f=new Font("Symbol",fontStyle,fontSize);
text.setFont(f);
System.out.println(f.getFamily());
}
if(command.equals("Regular"))
{
String fontName=f.getName();
String fontFamily=f.getFamily();
int fontSize=f.getSize();
int fontStyle=f.getStyle();

f=new Font(fontName,Font.PLAIN,fontSize);
text.setFont(f);
}
if(command.equals("Bold"))
{
String fontName=f.getName();
String fontFamily=f.getFamily();
int fontSize=f.getSize();
int fontStyle=f.getStyle();

f=new Font(fontName,Font.BOLD,fontSize);
text.setFont(f);
}
if(command.equals("Italic"))
{
String fontName=f.getName();
String fontFamily=f.getFamily();
int fontSize=f.getSize();
int fontStyle=f.getStyle();

f=new Font(fontName,Font.ITALIC,fontSize);
text.setFont(f);
}
if(command.equals("Bold Italic"))
{
String fontName=f.getName();
String fontFamily=f.getFamily();
int fontSize=f.getSize();
int fontStyle=f.getStyle();

f=new Font(fontName,Font.BOLD|Font.ITALIC,fontSize);
text.setFont(f);
}

if(command.equals("12"))
{
String fontName=f.getName();
String fontFamily=f.getFamily();
int fontSize=f.getSize();
int fontStyle=f.getStyle();

f=new Font(fontName,fontStyle,12);
text.setFont(f);
}

if(command.equals("14"))
{
String fontName=f.getName();
String fontFamily=f.getFamily();
int fontSize=f.getSize();
int fontStyle=f.getStyle();

f=new Font(fontName,fontStyle,14);
text.setFont(f);
}
if(command.equals("18"))
{
String fontName=f.getName();
String fontFamily=f.getFamily();
int fontSize=f.getSize();
int fontStyle=f.getStyle();

f=new Font(fontName,fontStyle,18);
text.setFont(f);
}
if(command.equals("20"))
{
String fontName=f.getName();
String fontFamily=f.getFamily();
int fontSize=f.getSize();
int fontStyle=f.getStyle();

f=new Font(fontName,fontStyle,20);
text.setFont(f);
}
if(command.equals("Select All (Ctrl+A)"))
{
String strText=text.getText();
int strLen=strText.length();
text.select(0,strLen);
}


}

public static void main(String args[])
{
Texteditor note = new Texteditor("Untitled-Notepad");
note.setSize(500,500);
note.setVisible(true);
}
}

Answer 2

我在Eclipse中构建的完整项目，这里是Github的链接：

https://github.com/devanshu-netwuk/DevPad-Java-Based-Text-Editor