我正在处理一个简单的注册窗口,当Java应用程序打开时会出现。
它是一个JFrame,其中包含一个JPanel,该JPanel具有文本字段、标签和另一个面板,该面板还包含文本字段和标签。我的问题是外部面板有一个背景图片,但它不适用于内部面板,如下图所示:
https://i.imgur.com/MTgNO3p.png
以下是整个窗口代码:
它是一个JFrame,其中包含一个JPanel,该JPanel具有文本字段、标签和另一个面板,该面板还包含文本字段和标签。我的问题是外部面板有一个背景图片,但它不适用于内部面板,如下图所示:
https://i.imgur.com/MTgNO3p.png
以下是整个窗口代码:
public void start() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
ex.printStackTrace();
}
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
frame = new JFrame("Chat");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//frame.setMaximumSize(new Dimension((int)screenSize.getWidth()-1000, (int)screenSize.getHeight()-1000));
frame.setMinimumSize(new Dimension((int)screenSize.getWidth()/2-200,(int) screenSize.getHeight()/2));
frame.setResizable(false);
welcome = new LoginPanel();
welcome.setLayout(new BoxLayout(welcome, BoxLayout.Y_AXIS));
welcome.setBorder(BorderFactory.createEmptyBorder(50, welcome.getWidth()/2-500, 50, welcome.getWidth()/2 -500));
//repaintThread = new Thread(new RepaintRunnable(frame, welcome));
//repaintThread.start();
request = new JLabel("Please fill the required fields below:");
request.setFont(new Font("Serif", Font.BOLD, 20));
request.setBorder(BorderFactory.createEmptyBorder(0, 0, 10, 0));
request.setAlignmentX(Component.CENTER_ALIGNMENT);
userInfo = new JPanel();
userInfo.setLayout(new BoxLayout(userInfo, BoxLayout.Y_AXIS));
userInfo.setAlignmentX(Component.CENTER_ALIGNMENT);
Font fieldType = new Font("Serif", Font.PLAIN, 15);
PlainDocument doc = new PlainDocument();
doc.setDocumentFilter(new NameDocument());
enterFirstName = new JLabel("First name:");
enterFirstName.setAlignmentX(Component.LEFT_ALIGNMENT);
enterFirstName.setFont(fieldType);
firstName = new JTextField(20);
firstName.setMaximumSize(firstName.getPreferredSize());
firstName.setDocument(NameDocument.getNewNameDocument(NameDocument.NO_SPACE));
firstName.getDocument().addDocumentListener(new ChangeDocumentListener());
firstName.addActionListener(new ConfirmListener());
firstName.setAlignmentX(Component.LEFT_ALIGNMENT);
enterSecName= new JLabel("Surname:");
enterSecName.setAlignmentX(Component.LEFT_ALIGNMENT);
enterSecName.setFont(fieldType);
secName = new JTextField(30);
secName.setMaximumSize(secName.getPreferredSize());
secName.setDocument(NameDocument.getNewNameDocument(NameDocument.HAS_SPACE));
secName.getDocument().addDocumentListener(new ChangeDocumentListener());
secName.addActionListener(new ConfirmListener());
secName.setAlignmentX(Component.LEFT_ALIGNMENT);
enterNickname = new JLabel("Nickname (how other people will see you in chat):");
enterNickname.setAlignmentX(Component.LEFT_ALIGNMENT);
enterNickname.setFont(fieldType);
nickname = new JTextField(30);
nickname.setMaximumSize(nickname.getPreferredSize());
nickname.setDocument(NameDocument.getNewNameDocument(NameDocument.NO_SPACE));
nickname.addActionListener(new ConfirmListener());
nickname.setAlignmentX(Component.LEFT_ALIGNMENT);
userInfo.add(enterFirstName);
userInfo.add(firstName);
userInfo.add(enterSecName);
userInfo.add(secName);
userInfo.add(enterNickname);
userInfo.add(nickname);
confirm = new JButton("Submit");
confirm.setAlignmentX(Component.CENTER_ALIGNMENT);
confirm.setEnabled(false);
confirm.addActionListener(new ConfirmListener());
welcome.add(request);
welcome.add(userInfo);
welcome.add(new Box.Filler(new Dimension(10, 10), new Dimension(10, 10), new Dimension(10, 10)));
welcome.add(confirm);
frame.getContentPane().add(BorderLayout.CENTER, welcome);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
这里是LoginPanel代码(外部JPanel):
public class LoginPanel extends JPanel {
public void paintComponent(Graphics g) {
try {
super.paintComponent(g);
BufferedImage background = ImageIO.read(new File("Background.jpg"));
g.drawImage(background, 0, 0, getWidth(), getHeight(), null);
} catch(Exception ex) {
ex.printStackTrace();
}
}
}
如果有人能给我一些建议,让这段代码更好,因为我是Java的初学者,那将会很棒。
frame.setMinimumSize(new Dimension((int)screenSize.getWidth()/2-200,(int) screenSize.getHeight()/2));
这是基于所需大小的猜测。在添加所有组件后,我会改为调用frame.pack();
然后立即调用frame.setMinimumSize(frame.getSize());
new Font("Serif", Font.PLAIN, 15);
最好改为new Font(Font.SERIF, Font.PLAIN, 15);
以进行编译时检查。g.drawImage(background, 0, 0, getWidth(), getHeight(), null);
最好改为g.drawImage(background, 0, 0, getWidth(), getHeight(), this);
(使用ImageObserver
)。