一个关于弹出菜单的问题``` 我想做一个右键弹出菜单``做出来后,发现菜单弹出后,总是默认选择了第一项```在网上下载了几个也是如此```,想请问高手,如何使菜单只是弹出,而不是还默认选择了某项```谢谢``` 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 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.JTextArea;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 * */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JTextArea * */ 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) { } }} 缓存 Spider读取网页最快的方法 swing如何设置焦点快捷键? 求助改变鼠标得外观 JAVA写的ftp 运行起来一切正常,功能也都能实现,但是运行到3个多小时就自动错误退出了 有人知道为什么吗? 给出三个点如何画弧? 一个需要真正高手来指导的socket读问题! 如何把JTree的模型提取成一个XML文件?必给分! 大家说java没有指针,是好还是坏呢,为什么c++中 求助!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! DepartmentException 在API找不到 想做一个JAVA简单的计算器 不知道怎么设计布局
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.JTextArea;
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
*
*/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JTextArea
*
*/
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) {
} }}