我正在NetBeans中开发应用程序。我有一些按钮，我想改变鼠标事件（的mouseEntered，...）在我的mouseEntered有以下代码：Java：更改jLabel前景色
private void jButton5MouseEntered(java.awt.event.MouseEvent evt) {
jButton5.setIcon(new ImageIcon(getClass().getResource("resources/menu2.png")));
jLabel1.setForeground(Color.RED);
}
我希望它改变该按钮的图标，我也想改变前景色我的jLabel1。我对那个jLabel1有问题。它不会改变。为什么？谢谢
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingConstants;
public class Main extends JFrame {
JLabel label1;
JLabel label2;
public Main() {
super("JLabel Demo");
setSize(600, 100);
JPanel content = new JPanel(new BorderLayout());
label1 = new JLabel("Java2s");
label1.setFont(new Font("Helvetica", Font.BOLD, 18));
label1.setOpaque(true);
label1.setBackground(Color.white);
content.add(label1, BorderLayout.WEST);
ImageIcon image = new ImageIcon(getClass().getResource("items.gif"));
label2 = new JLabel("Java2s", image, SwingConstants.RIGHT);
label2.setVerticalTextPosition(SwingConstants.TOP);
label2.setOpaque(true);
label2.setBackground(Color.white);
content.add(label2, BorderLayout.CENTER);
JButton btn = new JButton("Change");
btn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
label1.setForeground(Color.RED);
label2.setIcon(new ImageIcon(getClass().getResource("menu_arrow.gif")));
}
});
content.add(btn, BorderLayout.EAST);
getContentPane().add(content);
setVisible(true);
}
public static void main(String args[]) {
new Main();
}
}
请尝试上面的代码，布局不好看，但我认为这可以解决您的问题。
+1好。必须阅读http://docs.oracle.com/javase/tutorial/uiswing/concurrency/initial.html – vels4j
@ vels4j还有关于'JFrame'：http://docs.oracle.com/javase/tutorial/uiswing/components /frame.html –
我正在NetBeans中开发它，这意味着当我创建我的jFrame表单时，那里已经有一些预生成的代码。这里是：
import java.awt.Color;
import java.awt.Component;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
/**
*
* @author Svist
*/
public class OsvetlenieForm extends javax.swing.JFrame {
/**
* Creates new form OsvetlenieForm
*/
public OsvetlenieForm() {
initComponents();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jLabel5 = new javax.swing.JLabel();
jLabel4 = new javax.swing.JLabel();
jLabel3 = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();
jButton4 = new javax.swing.JButton();
jButton3 = new javax.swing.JButton();
jButton5 = new javax.swing.JButton();
jButton2 = new javax.swing.JButton();
jLabel1 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.DISPOSE_ON_CLOSE);
setTitle("Osvetlenie");
setMinimumSize(new java.awt.Dimension(900, 600));
setResizable(false);
getContentPane().setLayout(null);
jLabel5.setFont(new java.awt.Font("Tunga", 0, 18)); // NOI18N
jLabel5.setForeground(new java.awt.Color(255, 255, 255));
jLabel5.setText("Pohodlie");
getContentPane().add(jLabel5);
jLabel5.setBounds(10, 320, 60, 20);
jLabel4.setFont(new java.awt.Font("Tunga", 0, 18)); // NOI18N
jLabel4.setForeground(new java.awt.Color(255, 255, 255));
jLabel4.setText("Bezpecnost");
getContentPane().add(jLabel4);
jLabel4.setBounds(10, 280, 90, 20);
jLabel3.setFont(new java.awt.Font("Tunga", 0, 18)); // NOI18N
jLabel3.setForeground(new java.awt.Color(255, 255, 255));
jLabel3.setText("Kúrenie");
getContentPane().add(jLabel3);
jLabel3.setBounds(10, 240, 70, 20);
jLabel2.setFont(new java.awt.Font("Tunga", 0, 18)); // NOI18N
jLabel2.setForeground(new java.awt.Color(55, 117, 121));
jLabel2.setText("Osvetlenie");
getContentPane().add(jLabel2);
jLabel2.setBounds(10, 200, 80, 14);
jButton4.setIcon(new javax.swing.ImageIcon(getClass().getResource("/resources/nic.png"))); // NOI18N
jButton4.setBorder(null);
jButton4.setBorderPainted(false);
jButton4.setContentAreaFilled(false);
jButton4.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseEntered(java.awt.event.MouseEvent evt) {
jButton4MouseEntered(evt);
}
public void mouseExited(java.awt.event.MouseEvent evt) {
jButton4MouseExited(evt);
}
});
getContentPane().add(jButton4);
jButton4.setBounds(0, 310, 180, 40);
jButton3.setIcon(new javax.swing.ImageIcon(getClass().getResource("/resources/nic.png"))); // NOI18N
jButton3.setBorder(null);
jButton3.setBorderPainted(false);
jButton3.setContentAreaFilled(false);
jButton3.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseEntered(java.awt.event.MouseEvent evt) {
jButton3MouseEntered(evt);
}
public void mouseExited(java.awt.event.MouseEvent evt) {
jButton3MouseExited(evt);
}
});
getContentPane().add(jButton3);
jButton3.setBounds(0, 270, 180, 40);
jButton5.setIcon(new javax.swing.ImageIcon(getClass().getResource("/resources/nic.png"))); // NOI18N
jButton5.setBorder(null);
jButton5.setBorderPainted(false);
jButton5.setContentAreaFilled(false);
jButton5.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseEntered(java.awt.event.MouseEvent evt) {
jButton5MouseEntered(evt);
}
public void mouseExited(java.awt.event.MouseEvent evt) {
jButton5MouseExited(evt);
}
});
getContentPane().add(jButton5);
jButton5.setBounds(0, 190, 177, 39);
jButton2.setIcon(new javax.swing.ImageIcon(getClass().getResource("/resources/nic.png"))); // NOI18N
jButton2.setBorder(null);
jButton2.setBorderPainted(false);
jButton2.setContentAreaFilled(false);
jButton2.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseEntered(java.awt.event.MouseEvent evt) {
jButton2MouseEntered(evt);
}
public void mouseExited(java.awt.event.MouseEvent evt) {
jButton2MouseExited(evt);
}
});
getContentPane().add(jButton2);
jButton2.setBounds(0, 230, 177, 39);
jLabel1.setIcon(new javax.swing.ImageIcon(getClass().getResource("/resources/menu.jpg"))); // NOI18N
getContentPane().add(jLabel1);
jLabel1.setBounds(0, 0, 900, 600);
pack();
java.awt.Dimension screenSize = java.awt.Toolkit.getDefaultToolkit().getScreenSize();
java.awt.Dimension dialogSize = getSize();
setLocation((screenSize.width-dialogSize.width)/2,(screenSize.height-dialogSize.height)/2);
}// </editor-fold>
private void jButton2MouseEntered(java.awt.event.MouseEvent evt) {
jButton2.setIcon(new ImageIcon(getClass().getResource("resources/menu2.png")));
}
private void jButton2MouseExited(java.awt.event.MouseEvent evt) {
jButton2.setIcon(new ImageIcon(getClass().getResource("resources/nic.png")));
}
private void jButton3MouseEntered(java.awt.event.MouseEvent evt) {
jButton3.setIcon(new ImageIcon("src/menu_over.png"));
}
private void jButton3MouseExited(java.awt.event.MouseEvent evt) {
jButton3.setIcon(new ImageIcon("src/menu2.png"));
}
private void jButton4MouseEntered(java.awt.event.MouseEvent evt) {
jButton4.setIcon(new ImageIcon("src/menu_over.png"));
}
private void jButton4MouseExited(java.awt.event.MouseEvent evt) {
jButton4.setIcon(new ImageIcon("src/menu2.png"));
}
private void jButton5MouseEntered(java.awt.event.MouseEvent evt) {
jButton5.setIcon(new ImageIcon(getClass().getResource("resources/menu2.png")));
jLabel1.setForeground(Color.RED);
}
private void jButton5MouseExited(java.awt.event.MouseEvent evt) {
jButton5.setIcon(new ImageIcon(getClass().getResource("resources/nic.png")));
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/*
* Set the Nimbus look and feel
*/
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/*
* If Nimbus (introduced in Java SE 6) is not available, stay with the
* default look and feel. For details see
* http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(OsvetlenieForm.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(OsvetlenieForm.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(OsvetlenieForm.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(OsvetlenieForm.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/*
* Create and display the form
*/
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new OsvetlenieForm().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton2;
private javax.swing.JButton jButton3;
private javax.swing.JButton jButton4;
private javax.swing.JButton jButton5;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JLabel jLabel5;
// End of variables declaration
private static class ComponentImpl extends Component {
public ComponentImpl() {
}
}
}
我有一个“图标”图片为我的按钮。当“MouseEntered”（这个工程很好）时，我希望这段代码改变我的按钮的“图标”图像，并且同时改变我的“jLabel1”的文本颜色，它是“前景（颜色）”参数。 （这部分不工作）。
这不是一个答案，应该[编辑]（http://stackoverflow.com/posts/14023775/edit）到问题中。 –
我改变了主意。 1）由于您想要更改***任何***标签的颜色，因此不需要其中的5个！或按钮。 2）为了更快地获得更好的帮助，请发布[SSCCE]（http://sscce.org/）。 3）作为一般提示。不要使用GUI设计器，直到您理解布局如何工作，并且决不会调用（或强制IDE编写调用的代码）'setBounds'。 –
似乎在这里工作得很好。
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class NimbusLabelColor {
public static void main(String[] args) {
Runnable r = new Runnable() {
@Override
public void run() {
try {
for (UIManager.LookAndFeelInfo info :
UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
System.out.println("Nimbus found!");
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (Exception e) {
e.printStackTrace();
}
JPanel gui = new JPanel(new GridLayout(3,1,2,2));
MouseAdapter adapter = new MouseAdapter() {
@Override
public void mouseEntered(MouseEvent me) {
Object c = me.getSource();
// do with extreme caution
JLabel l = (JLabel)c;
l.setForeground(Color.RED);
}
@Override
public void mouseExited(MouseEvent me) {
Object c = me.getSource();
// do with extreme caution
JLabel l = (JLabel)c;
l.setForeground(Color.BLUE);
}
};
for (int ii=0; ii<3; ii++) {
JLabel l = new JLabel("Float Me!");
l.addMouseListener(adapter);
gui.add(l);
}
JOptionPane.showMessageDialog(null, gui);
}
};
// Swing GUIs should be created and updated on the EDT
SwingUtilities.invokeLater(r);
}
}
很好的例子，谢谢 – Alaeddine
那么没有必要做那么多冗长的代码，你有一个简单的使用鼠标输入的事件的所需选项。如下
private void jMenu1MouseEntered(java.awt.event.MouseEvent evt) {
this.jMenu1.setBackground(Color.red);
this.jMenu1.setForeground(Color.red);
System.out.println("Mouse Entered in Manu 1");
}
这会有所帮助。
我创建了一个简单的应用程序来显示通过鼠标事件更改标签组件的方式。在按钮中，我添加了一个鼠标监听器，它是实现MouseListener接口的内部类。作为补充，我实现了两个方法：mouseExited和mouseEntered。当鼠标退出按钮区域时，用于显示标签初始状态的第一种方法将恢复为原始状态。第二种方法在鼠标位于按钮区域时显示标签更改。
我希望它可以帮助你或更多的人。
public class MouseChangeLabel {
private JFrame frame;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
MouseChangeLabel window = new MouseChangeLabel();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public MouseChangeLabel() {
initialize();
}
private void initialize() {
frame = new JFrame();
frame.setBounds(0, 0, 200, 150);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
JLabel lblLabel1 = new JLabel("Label 1 without Panel");
lblLabel1.setHorizontalAlignment(SwingConstants.CENTER);
lblLabel1.setBounds(30, 10, 150, 30);
lblLabel1.setForeground(Color.BLACK);
frame.getContentPane().add(lblLabel1);
JButton btnButton = new JButton("Button 1");
btnButton.setBounds(30, 50, 150, 30);
btnButton.addMouseListener(new MouseListener() {
@Override
public void mouseReleased(MouseEvent e) {
// TODO Auto-generated method stub
}
@Override
public void mousePressed(MouseEvent e) {
// TODO Auto-generated method stub
}
@Override
public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub
lblLabel1.setForeground(Color.BLACK);
}
@Override
public void mouseEntered(MouseEvent e) {
// TODO Auto-generated method stub
lblLabel1.setForeground(Color.RED);
}
@Override
public void mouseClicked(MouseEvent e) {
// TODO Auto-generated method stub
}
});
frame.getContentPane().add(btnButton);
}
}
首先检查是否通过放入System.out.println（“Called”）来调用此方法。在里面。如果是这样，请尝试调用repaint：（JFrame的名称）.repaint（）; – Aaron
你能否展示一些更相关的代码？只有这个很难看到有什么问题。 – Aaron
Javadocs：设置此组件的前景色。尊重这个属性取决于外观和感觉，有些人可能会选择忽视它。 –