Question

我正在开发netbeans中的app。我有一些按钮，我想在鼠标事件上更改（MouseEntered，...）在MouseEntered我有以下代码：

private void jButton5MouseEntered(java.awt.event.MouseEvent evt) {
      jButton5.setIcon(new ImageIcon(getClass().getResource("resources/menu2.png")));
       jLabel1.setForeground(Color.RED);
}

我想要它改变那个按钮的图标，我也想改变我的jLabel1的前景色。我有jLabel1的问题。它不会改变。为什么？谢谢

Answer 1

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。

Answer 2

似乎在这里工作得很好。

Nimbus Label Color

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);
    }
}

Answer 3

没有必要做那么冗长的代码，你有一个简单而理想的使用鼠标输入事件的选项。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。

Answer 4

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法。在按钮中，我添加了一个鼠标侦听器，它是一个实现MouseListener接口的内部类。作为补充，我实现了两个方法：mouseExited和mouseEntered。第一种方法，我用来显示标签的初始状态，当鼠标退出按钮区域时返回原始状态。当鼠标位于按钮区域时，第二种方法会显示标签更改。

我希望它可以帮助你或更多人。

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);
    }
}

Answer 5

我正在netbeans中开发它，这意味着，当我创建我的jFrame表单时，那里已经有一些预先生成的代码。这是：

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() {
    }
}
}

我的按钮有一个“图标”图片。我想要这个代码改变我的按钮的“图标”图像，当“MouseEntered”（这很好用），同时改变我的“jLabel1”的文本颜色，这是“前景（颜色）”参数。（这部分不起作用）。

Java：更改jLabel前景色

5 个答案: