私は非常に単純なJFrameを持っています。3つのメインパネルがあります。上部のバナー画像、左側のボタンのリスト、およびユーザーがログイン情報を入力してアプリケーションの残りの部分にアクセスするメインパネルです。
私はGridBagLayoutを使用しており、ほとんどの人が疫病のようにそれを避けているにもかかわらず、それはミックスに多くのコード行を追加しますが、私には非常に簡単です。ただし、一番上の行（バナー画像）が一番下の行（ボタンとログインパネル）と重なっているという奇妙な問題が発生しています。私はチェックして再チェックし、答えをウェブ全体で探しましたが、私が間違っていることを理解できません。
基本的に、一番下の行はJFrame全体の垂直方向の中央に配置され、2番目のGridBag行の中央には配置されません。そして、事前に画面に追加されているにもかかわらず、どういうわけか、BannerPanelがその上に描画されています。BannerPanelの動作と関係があると思いますが、回避策を見つけることができません。
これはどのように見えるかです：
https://sphotos-a.xx.fbcdn.net/hphotos-snc7/375898_3720190211823_1073177291_n.jpg
これはそれがどのように見えるべきかです：
https://sphotos-a.xx.fbcdn.net/hphotos-ash4/314993_3720190291825_1429407717_n.jpg
これが私のコードです：
public class LoginWindow extends JFrame implements ActionListener {
final static String unlockCode = "unlock";
ArrayList <User> userlist = new ArrayList <User> ();
User user = null;
// The visible parts of the window
GridBagConstraints gridbag;
JLabel inputLabel, errorLabel, lockedLabel, unlockLabel;
JTextField usernameField, unlockField;
JPasswordField passwordField;
JPanel inputPanel, usernamePanel, passwordPanel, unlockPanel;
public static void main(String[] args) {
LoginWindow win = new LoginWindow ();
win.userlist.add(new User ("username", "password", true));
}
public LoginWindow () {
setTitle("Login");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
getContentPane().setBackground(Color.GRAY);
setSize(640, 480);
setResizable(false);
resetGridbag();
// This is where I declare all the JLabels, JPanels, etc
inputLabel = new JLabel ("Secure Login");
inputLabel.setFont(new Font ("SansSerif", Font.BOLD, 24));
inputLabel.setForeground(Color.WHITE);
JLabel usernameLabel = new JLabel ("Username ");
usernameLabel.setForeground(Color.WHITE);
usernameField = new JTextField (10);
usernameField.setActionCommand("Login");
usernameField.addActionListener(this);
usernamePanel = new JPanel ();
usernamePanel.setBackground(Color.GRAY);
usernamePanel.add(usernameLabel);
usernamePanel.add(usernameField);
JLabel passwordLabel = new JLabel ("Password ");
passwordLabel.setForeground(Color.WHITE);
passwordField = new JPasswordField (10);
passwordField.setActionCommand("Login");
passwordField.addActionListener(this);
passwordPanel = new JPanel ();
passwordPanel.setBackground(Color.GRAY);
passwordPanel.add(passwordLabel);
passwordPanel.add(passwordField);
errorLabel = new JLabel ("");
errorLabel.setForeground(Color.WHITE);
lockedLabel = new JLabel ("You've been locked out!");
lockedLabel.setForeground(Color.WHITE);
unlockLabel = new JLabel ("Unlock Code");
unlockLabel.setForeground(Color.WHITE);
unlockField = new JTextField (10);
unlockField.setActionCommand("Unlock");
unlockField.addActionListener(this);
unlockPanel = new JPanel ();
unlockPanel.setBackground(Color.GRAY);
unlockPanel.add(unlockLabel);
unlockPanel.add(unlockField);
JLabel newPassword = new JLabel ("Request a new password");
newPassword.setForeground(Color.WHITE);
JPanel optionPanel = new JPanel ();
optionPanel.setBackground(Color.GRAY);
optionPanel.add(newPassword);
inputPanel = new JPanel ();
inputPanel.setBackground(Color.GRAY);
inputPanel.setLayout(new GridBagLayout ());
// Now I'm going to add them all to the screen
GridBagLayout gbl = new GridBagLayout ();
gbl.columnWeights = new double [] {0.0f, 1.0f};
gbl.rowWeights = new double [] {0.0f, 1.0f};
setLayout(gbl);
gridbag.gridwidth = 2;
gridbag.gridy = 0;
gridbag.fill = GridBagConstraints.HORIZONTAL;
add(new BannerPanel (), gridbag);
gridbag.gridy = 1;
gridbag.gridwidth = 1;
gridbag.anchor = GridBagConstraints.NORTHWEST;
add(optionPanel, gridbag);
gridbag.gridx++;
gridbag.anchor = GridBagConstraints.CENTER;
add(inputPanel, gridbag);
redraw();
setVisible(true);
}
public void resetGridbag () {
gridbag = new GridBagConstraints ();
gridbag.anchor = GridBagConstraints.CENTER;
gridbag.gridx = gridbag.gridy = 0;
}
public void reset () {
inputPanel.removeAll();
resetGridbag();
validate();
repaint();
}
public void redraw () {
reset();
if (user == null || !user.locked()) {
inputPanel.add(inputLabel, gridbag);
gridbag.gridy++;
inputPanel.add(new JLabel (" "), gridbag);
gridbag.gridy++;
inputPanel.add(usernamePanel, gridbag);
gridbag.gridy++;
inputPanel.add(passwordPanel, gridbag);
gridbag.gridy++;
inputPanel.add(new JLabel (" "), gridbag);
gridbag.gridy++;
inputPanel.add(errorLabel, gridbag);
}
else {
inputPanel.add(lockedLabel, gridbag);
gridbag.gridy++;
inputPanel.add(unlockPanel, gridbag);
gridbag.gridy++;
inputPanel.add(errorLabel, gridbag);
errorLabel.setText("");
}
validate();
repaint();
}
public void actionPerformed (ActionEvent e) {
String button = e.getActionCommand();
if (button.equals("Login")) {
boolean usernameMatch = false;
boolean passwordMatch = false;
for (int i = 0; i < userlist.size(); i++) {
if (usernameField.getText().equals(userlist.get(i).username())) {
usernameMatch = true;
user = userlist.get(i);
}
if (new String (passwordField.getPassword()).equals(userlist.get(i).password()))
passwordMatch = true;
}
passwordField.setText("");
if (usernameMatch) {
if (passwordMatch) {
user.unlock();
//new MainWindow ();
dispose();
}
else {
user.loginFail();
if (!user.locked())
errorLabel.setText("Login unsuccessful. " +
user.loginAttempts() + " attempts left!");
else
redraw();
}
}
else
errorLabel.setText("Login unsuccessful.");
validate();
}
else if (button.equals("Unlock")) {
if (unlockField.getText().equals(unlockCode)) {
errorLabel.setText("");
user.unlock();
redraw();
}
else {
errorLabel.setText("Invalid unlock code.");
validate();
}
unlockField.setText("");
}
}
}
class BannerPanel extends JPanel {
Image image;
int width = 0, height = 0;
double ratio = 0.0;
public BannerPanel () {
try {
image = ImageIO.read(BannerPanel.class
.getClassLoader().getResourceAsStream("banner.png"));
}
catch (Exception e) { e.printStackTrace(); }
}
@Override
protected void paintComponent (Graphics g) {
super.paintComponent(g);
ratio = (double) getWidth() / image.getWidth(null);
width = getWidth();
height = getImageHeight();
setSize(width, height);
if (image != null) {
g.drawImage(image, 0, 0, width, height, this);
}
}
public int getImageHeight () {
return (int) (image.getHeight(null) * ratio);
}
}
public class User {
String username = "";
String password = "";
boolean superuser = false;
int loginAttempts = 3;
public User (String username, String password, boolean superuser) {
this.username = username;
this.password = password;
this.superuser = superuser;
}
public String username () {
return username;
}
public String password () {
return password;
}
public boolean superuser () {
return superuser;
}
public int loginAttempts () {
return loginAttempts;
}
public void loginFail () {
if (loginAttempts > 0)
loginAttempts--;
}
public boolean locked () {
return (loginAttempts == 0);
}
public void lock () {
loginAttempts = 0;
}
public void unlock () {
loginAttempts = 3;
}
}