我正在开发 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，它会覆盖用于设计 GUI 的所有组件。
首先我的没有背景图片的表格如下图所示，
我的代码是，
登录.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();
}
}
});
}
}
登录面板.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();
}
}
}
设置背景图像后，它看起来像这样，
它隐藏了JButton,的组件JLabel。
