java JTextArea 实现不可修改文本内容、右键菜单

最近在写聊天室...显示的文本框内容应该是不可以修改只能复制，但是JFC没有提供那种是否只可读的属性。

我从网上有看到有人写好了这种类，然后自己又添加了右键菜单出现复制、粘贴、剪切的功能

摘自https://www.360docs.net/doc/762864162.html,/mq612的源代码:

import java.awt.datatransfer.Clipboard;

import java.awt.datatransfer.DataFlavor;

import java.awt.datatransfer.Transferable;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.InputEvent;

import java.awt.event.MouseEvent;

import java.awt.event.MouseListener;

import javax.swing.JFrame;

import javax.swing.JMenuItem;

import javax.swing.JPopupMenu;

import javax.swing.JScrollPane;

import javax.swing.JT extArea;

import javax.swing.KeyStroke;

import javax.swing.UIManager;

/**

* Java右键菜单实现文本组件内容的的复制、粘贴、剪切功能

*

* @author 五斗米<如转载请保留作者和出处>

* @bloghttps://www.360docs.net/doc/762864162.html,/mq612

*/

public class Test extends JFrame {

private static final long serialVersionUID = -5942087991012920147L;

private JScrollPane pane = null;

private TextAreaMenu text = null;

public Test() {

super("右键菜单");

try { // 使用Windows的界面风格

UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");

} catch (Exception e) {

e.printStackTrace();

}

text = new TextAreaMenu();

pane = new JScrollPane(text);

this.getContentPane().add(pane);

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

this.setSize(300, 200);

this.setVisible(true);

}

public static void main(String args[]) {

new Test();

}

/**

* 带有功能菜单的JT extArea

*

* @author 五斗米<如转载请保留作者和出处>

* @bloghttps://www.360docs.net/doc/762864162.html,/mq612

*/

class TextAreaMenu extends JTextArea implements MouseListener { private static final long serialVersionUID = -2308615404205560110L;

private JPopupMenu pop = null; // 弹出菜单

private JMenuItem copy = null, paste = null, cut = null; // 三个功能菜单public TextAreaMenu() {

super();

init();

}

private void init() {

this.addMouseListener(this);

pop = new JPopupMenu();

pop.add(copy = new JMenuItem("复制"));

pop.add(paste = new JMenuItem("粘贴"));

pop.add(cut = new JMenuItem("剪切"));

copy.setAccelerator(KeyStroke.getKeyStroke('C', InputEvent.CTRL_MASK)); paste.setAccelerator(KeyStroke.getKeyStroke('V', InputEvent.CTRL_MASK)); cut.setAccelerator(KeyStroke.getKeyStroke('X', InputEvent.CTRL_MASK)); copy.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

action(e);

}

});

paste.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

action(e);

}

});

cut.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

action(e);

}

});

this.add(pop);

}

/**

* 菜单动作

* @param e

*/

public void action(ActionEvent e) {

String str = e.getActionCommand();

if (str.equals(copy.getText())) { // 复制

this.copy();

} else if (str.equals(paste.getText())) { // 粘贴this.paste();

} else if (str.equals(cut.getText())) { // 剪切this.cut();

}

}

public JPopupMenu getPop() {

return pop;

}

public void setPop(JPopupMenu pop) {

this.pop = pop;

}

/**

* 剪切板中是否有文本数据可供粘贴

*

* @return true为有文本数据

*/

public boolean isClipboardString() {

boolean b = false;

Clipboard clipboard = this.getToolkit().getSystemClipboard(); Transferable content = clipboard.getContents(this);

try {

if (content.getTransferData(DataFlavor.stringFlavor) instanceof String) {

b = true;

}

} catch (Exception e) {

}

return b;

}

/**

* 文本组件中是否具备复制的条件

*

* @return true为具备

*/

public boolean isCanCopy() {

boolean b = false;

int start = this.getSelectionStart();

int end = this.getSelectionEnd();

if (start != end)

b = true;

return b;

}

public void mouseClicked(MouseEvent e) {

}

public void mouseEntered(MouseEvent e) {

}

public void mouseExited(MouseEvent e) {

}

public void mousePressed(MouseEvent e) {

if (e.getButton() == MouseEvent.BUTTON3) { copy.setEnabled(isCanCopy());

paste.setEnabled(isClipboardString());

cut.setEnabled(isCanCopy());

pop.show(this, e.getX(), e.getY());

}

}

public void mouseReleased(MouseEvent e) {

}

}

}

我修改后可实现右键单击菜单、只可复制不可修改的代码

public class NoEditArea extends JT extArea implements MouseListener{

//以下代码实现右键复制功能

private static final long serialVersionUID = -2308615404205560110L;

private JPopupMenu pop = null; // 弹出菜单

private JMenuItem copy = null, paste = null, cut = null; // 三个功能菜单private void init() {

this.addMouseListener(this);

pop = new JPopupMenu();

pop.add(copy = new JMenuItem("复制"));

copy.setAccelerator(KeyStroke.getKeyStroke('C', InputEvent.CTRL_MASK)); copy.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

action(e);

}

});

this.add(pop);

}

public void action(ActionEvent e) {

String str = e.getActionCommand();

if (str.equals(copy.getT ext())) { // 复制

this.copy();

}

}

public JPopupMenu getPop() {

return pop;

}

public void setPop(JPopupMenu pop) { this.pop = pop;

}

//文本组件是否具备复制的条件

public boolean isCanCopy() {

boolean b = false;

int start = this.getSelectionStart();

int end = this.getSelectionEnd();

if (start != end)

b = true;

return b;

}

public void mouseClicked(MouseEvent e) {

}

public void mouseEntered(MouseEvent e) { }

public void mouseExited(MouseEvent e) {

}

public void mousePressed(MouseEvent e) {

if (e.getButton() == MouseEvent.BUTTON3) {

copy.setEnabled(isCanCopy());

pop.show(this, e.getX(), e.getY());

}

}

public void mouseReleased(MouseEvent e) {

}

//以下代码实现不可修改文本框内容

public NoEditArea(/*String string,int rows,int columns*/){

super(/*string,rows,columns*/);

init();

addKeyListener(new KeyAdapter(){

public void keyTyped(KeyEvent key) {

key.consume();

}

public void keyPressed(KeyEvent key) {

JTextArea temp = (JTextArea)key.getSource();

int caretPos = temp.getCaretPosition();

switch(key.getKeyCode()){

case(KeyEvent.VK_LEFT):

case(KeyEvent.VK_BACK_SPACE):if(caretPos>0){temp.setCaretPosition(caretPos -1);}break;

case(KeyEvent.VK_RIGHT):if(caretPos

case(KeyEvent.VK_DELETE):System.out.println("aaa");break;

default:break;

}

key.consume();

}

public void keyReleased(KeyEvent key) {

key.consume();

}

});

}

}

NoEditArea已经封装好，直接用就可以了

如果是普通的JTextArea，实现右键复制、粘贴、剪贴功能

public class EditArea extends JTextArea implements MouseListener

{

public EditArea()

{

super();

init();

}

// 以下代码实现右键复制功能

private static final long serialVersionUID = -2308615404205560110L;

private JPopupMenu pop = null; // 弹出菜单

private JMenuItem copy = null, paste = null, cut = null; // 三个功能菜单private void init() {

this.addMouseListener(this);

pop = new JPopupMenu();

pop.add(copy = new JMenuItem("复制"));

pop.add(paste = new JMenuItem("粘贴"));

pop.add(cut = new JMenuItem("剪切"));

copy.setAccelerator(KeyStroke.getKeyStroke('C', InputEvent.CTRL_MASK)); paste.setAccelerator(KeyStroke.getKeyStroke('V', InputEvent.CTRL_MASK)); cut.setAccelerator(KeyStroke.getKeyStroke('X', InputEvent.CTRL_MASK)); copy.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

action(e);

}

});

paste.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

action(e);

}

});

cut.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

action(e);

}

});

this.add(pop);

public void action(ActionEvent e) {

String str = e.getActionCommand();

if (str.equals(copy.getT ext())) { // 复制

this.copy();

} else if (str.equals(paste.getText())) { // 粘贴

this.paste();

} else if (str.equals(cut.getText())) { // 剪切

this.cut();

}

}

public JPopupMenu getPop() {

return pop;

}

public void setPop(JPopupMenu pop) {

this.pop = pop;

}

//是否具备粘贴的条件

public boolean isClipboardString() {

boolean b = false;

Clipboard clipboard = this.getT oolkit().getSystemClipboard(); Transferable content = clipboard.getContents(this);

try {

if (content.getTransferData(DataFlavor.stringFlavor) instanceof String) {

b = true;

}

}catch(Exception e){

return b;

}

//文本组件是否具备复制的条件

public boolean isCanCopy() {

boolean b = false;

int start = this.getSelectionStart();

int end = this.getSelectionEnd();

if (start != end)

b = true;

return b;

}

public void mouseClicked(MouseEvent e) {

}

public void mouseEntered(MouseEvent e) { }

public void mouseExited(MouseEvent e) { }

public void mousePressed(MouseEvent e) {

if (e.getButton() == MouseEvent.BUTTON3) { copy.setEnabled(isCanCopy());

paste.setEnabled(isClipboardString());

cut.setEnabled(isCanCopy());

pop.show(this, e.getX(), e.getY());

}

}

public void mouseReleased(MouseEvent e) {

}