背景图像隐藏所有GUI设计组件

我正在使用GUI应用程序，我使用swing组件来设计GUI。 我想为我的表单设置背景图像，但是当我设置图像时，它会重叠用于设计GUI的所有组件。

首先我没有背景图片的表格如下所示，

我的代码是，

Login.java

public class Login extends JFrame{ public static JFrame myFrame; public LoginPanel loginPanel; public Login() throws IOException { initilize(); } public void initilize()throws IOException { myFrame = new JFrame("Message"){ private Image backgroundImage = ImageIO.read(new File("D:/Sky.jpg")); public void paint( Graphics g ) { super.paint(g); g.drawImage(backgroundImage, 0, 0, null); } }; myFrame.setLayout(new BorderLayout()); loginPanel = new LoginPanel(); //Panel Container c = myFrame.getContentPane(); c.add(loginPanel, BorderLayout.WEST); myFrame.setSize(300, 150); myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); myFrame.setVisible(true); myFrame.setLocationRelativeTo(null); } public static void main(String[] arg) { SwingUtilities.invokeLater(new Runnable() { public void run() { try { new Login(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }); } } 

LoginPanel.java

 public class LoginPanel extends JPanel implements ActionListener { public JLabel user_no=null; public JLabel password=null; public JButton btn_login = null; public JButton btn_newUser = null; public JTextField usernameField=null; public JPasswordField passwordField=null; public static String userNo; public ArrayList msgList = new ArrayList(); public LoginPanel() { initilize(); initConnection(); } private void initilize() { Dimension size = getPreferredSize(); size.width = 285; size.height = 150; setPreferredSize(size); setBorder(BorderFactory.createTitledBorder(null, "Login Details", TitledBorder.CENTER, TitledBorder.TOP)); user_no = new JLabel("User No : "); password = new JLabel("Password : "); usernameField = new JTextField(14); passwordField = new JPasswordField(14); btn_login = new JButton("Login"); btn_newUser = new JButton("New User"); setLayout(new GridBagLayout()); GridBagConstraints gc = new GridBagConstraints(); //// First column ///////////////////////// gc.anchor = GridBagConstraints.LINE_START; gc.gridx = 0; gc.gridy = 0; add(user_no, gc); gc.gridx = 0; gc.gridy = 1; add(password, gc); //// Second column gc.anchor = GridBagConstraints.LINE_START; gc.gridx = 1; gc.gridy = 0; add(usernameField, gc); gc.gridx = 1; gc.gridy = 1; add(passwordField, gc); // Final row gc.anchor = GridBagConstraints.FIRST_LINE_START; gc.gridx = 1; gc.gridy = 2; add(btn_login, gc); gc.anchor = GridBagConstraints.FIRST_LINE_END; gc.gridx = 1; gc.gridy = 2; add(btn_newUser, gc); } private void initConnection() { btn_login.addActionListener(this); btn_newUser.addActionListener(this); } @Override public void actionPerformed(ActionEvent e) { if(e.getSource().equals(btn_login)) { userNo = usernameField.getText(); String userPwd = passwordField.getText(); System.out.println(userNo+" "+userPwd); Connection con = ConnectionImpl.getConnection(); try { PreparedStatement pstmt; String sql = "SELECT sender_no,pwd FROM tb_login where sender_no ='"+userNo+"'"; pstmt= con.prepareStatement(sql); ResultSet rs = pstmt.executeQuery(); if(rs.next()) { if(userNo.equalsIgnoreCase(rs.getString(1))&&userPwd.equalsIgnoreCase(rs.getString(2))) { System.out.println("Successfull login"); String sql2 = "Select msg from tb_msg where sender_no='"+userNo+"'"; pstmt= con.prepareStatement(sql2); ResultSet rs2 = pstmt.executeQuery(); while(rs2.next()) { msgList.add(rs2.getString(1)); } System.out.println("msgList = "+msgList.size()); Login.myFrame.dispose(); new AddMessage(userNo,msgList); } } } catch (Exception exp) { exp.printStackTrace(); } } if(e.getSource().equals(btn_newUser)) { Login.myFrame.dispose(); new NewUser(); } } } 

设置背景图片后，它看起来像这样，

它隐藏了JButton ， JLabel组件。

Answer 1

1. 将Image绘制到LoginPanel (JPanel)而不是ContentPane （不是直接绘制到JFrame好的idead）

2. 为JPanel使用paintComponent( ）而不是paint(for JFrame ）

Answer 2

代码需要更接近于此：

 import java.awt.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.image.BufferedImage; import javax.imageio.ImageIO; import javax.swing.*; import java.io.*; import java.sql.*; import java.util.ArrayList; import javax.swing.border.TitledBorder; public class Login extends JFrame{ public static JFrame myFrame; public LoginPanel loginPanel; public Login() throws IOException { initilize(); } public void initilize()throws IOException { BufferedImage backgroundImage = new BufferedImage(400,200,BufferedImage.TYPE_INT_RGB); myFrame = new JFrame("Message"); myFrame.setLayout(new BorderLayout()); loginPanel = new LoginPanel(backgroundImage); //Panel Container c = myFrame.getContentPane(); c.add(loginPanel, BorderLayout.WEST); //myFrame.setSize(300, 150); myFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); myFrame.pack(); myFrame.setVisible(true); myFrame.setLocationRelativeTo(null); } public static void main(String[] arg) { SwingUtilities.invokeLater(new Runnable() { public void run() { try { new Login(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }); } } class LoginPanel extends JPanel implements ActionListener { public JLabel user_no=null; public JLabel password=null; public JButton btn_login = null; public JButton btn_newUser = null; public JTextField usernameField=null; public JPasswordField passwordField=null; public static String userNo; public ArrayList msgList = new ArrayList(); private BufferedImage backgroundImage; public LoginPanel(BufferedImage backgroundImage) { this.backgroundImage = backgroundImage; initilize(); initConnection(); } public void paintComponent(Graphics g) { super.paintComponent(g); g.drawImage(backgroundImage, 0, 0, getWidth(), getHeight(), this); } private void initilize() { Dimension size = getPreferredSize(); size.width = 285; size.height = 150; setPreferredSize(size); setBorder(BorderFactory.createTitledBorder(null, "Login Details", TitledBorder.CENTER, TitledBorder.TOP)); user_no = new JLabel("User No : "); password = new JLabel("Password : "); usernameField = new JTextField(14); passwordField = new JPasswordField(14); btn_login = new JButton("Login"); btn_newUser = new JButton("New User"); setLayout(new GridBagLayout()); GridBagConstraints gc = new GridBagConstraints(); //// First column ///////////////////////// gc.anchor = GridBagConstraints.LINE_START; gc.gridx = 0; gc.gridy = 0; add(user_no, gc); gc.gridx = 0; gc.gridy = 1; add(password, gc); //// Second column gc.anchor = GridBagConstraints.LINE_START; gc.gridx = 1; gc.gridy = 0; add(usernameField, gc); gc.gridx = 1; gc.gridy = 1; add(passwordField, gc); // Final row gc.anchor = GridBagConstraints.FIRST_LINE_START; gc.gridx = 1; gc.gridy = 2; add(btn_login, gc); gc.anchor = GridBagConstraints.FIRST_LINE_END; gc.gridx = 1; gc.gridy = 2; add(btn_newUser, gc); } private void initConnection() { btn_login.addActionListener(this); btn_newUser.addActionListener(this); } @Override public void actionPerformed(ActionEvent e) { if(e.getSource().equals(btn_login)) { userNo = usernameField.getText(); String userPwd = passwordField.getText(); System.out.println(userNo+" "+userPwd); Connection con = null; try { PreparedStatement pstmt; String sql = "SELECT sender_no,pwd FROM tb_login where sender_no ='"+userNo+"'"; pstmt= con.prepareStatement(sql); ResultSet rs = pstmt.executeQuery(); if(rs.next()) { if(userNo.equalsIgnoreCase(rs.getString(1))&&userPwd.equalsIgnoreCase(rs.getString(2))) { System.out.println("Successfull login"); String sql2 = "Select msg from tb_msg where sender_no='"+userNo+"'"; pstmt= con.prepareStatement(sql2); ResultSet rs2 = pstmt.executeQuery(); while(rs2.next()) { msgList.add(rs2.getString(1)); } System.out.println("msgList = "+msgList.size()); Login.myFrame.dispose(); //new AddMessage(userNo,msgList); } } } catch (Exception exp) { exp.printStackTrace(); } } if(e.getSource().equals(btn_newUser)) { Login.myFrame.dispose(); //new NewUser(); } } } 

进一步提示

1. 为了更好地提供帮助，请发布SSCCE 。
2. 不要扩展框架，只使用实例，但..
3. 在这种情况下，根本不使用框架，而是在JDialog或JOptionPane显示登录。