我正在制作一个记分计划,但我遇到了一个问题。我试图做的是在顶部有一个包含两个JPanel的JPanel,而JPanel又包含两个团队名称。我很困惑为什么程序顶部的两个JLabel没有集中在它们所包含的JPanel中。
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ScoreFrame extends JFrame {
private static final Dimension SCREEN_SIZE = Toolkit.getDefaultToolkit().getScreenSize();
private static final int WIDTH = SCREEN_SIZE.width;
private static final int HEIGHT = SCREEN_SIZE.height;
private final JTextField[] nameField = new JTextField[] { new JTextField(), new JTextField() };
private final JLabel[] nameLabel = new JLabel[] { new JLabel("Team 1"), new JLabel("Team 2") };
private final GridBagLayout gridBag = new GridBagLayout();
private final GridBagConstraints constraints = new GridBagConstraints();
private final JPanel topPanel = new JPanel();
public ScoreFrame() {
super();
setResizable(false);
setSize(SCREEN_SIZE);
setLayout(gridBag);
setUndecorated(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
addKeyListener(new EscapeListener());
addComponents();
}
private void addComponents() {
addToTopPanel();
constraints.insets = new Insets(0, 0, (int) (HEIGHT * (double) 4 / 5), 0);
gridBag.setConstraints(topPanel, constraints);
add(topPanel);
}
private void addToTopPanel() {
final JPanel[] teamPanel = new JPanel[] { new JPanel(), new JPanel() };
topPanel.setLayout(gridBag);
topPanel.setSize(new Dimension(WIDTH, HEIGHT / 5));
Dimension teamPanelSize = new Dimension(WIDTH / 2, HEIGHT / 5);
teamPanel[0].setSize(teamPanelSize);
teamPanel[1].setSize(teamPanelSize);
Font nameFont = new Font("Times New Roman", Font.PLAIN, 50);
nameLabel[0].setFont(nameFont);
nameLabel[1].setFont(nameFont);
teamPanel[0].add(nameLabel[0]);
teamPanel[1].add(nameLabel[1]);
gridBag.setConstraints(teamPanel[0], constraints);
constraints.gridx = 1;
gridBag.setConstraints(teamPanel[1], constraints);
topPanel.add(teamPanel[0]);
topPanel.add(teamPanel[1]);
}
public void paint(Graphics g) {
super.paint(g);
int strokeSize = ((WIDTH + HEIGHT) / 2) / 300;
if (strokeSize < 1) {
strokeSize = 1;
}
final int fontSize = (int) (strokeSize * 12.5);
Graphics2D g2d = (Graphics2D) g;
g2d.setStroke(new BasicStroke(strokeSize));
g.drawLine(WIDTH / 2, 0, WIDTH / 2, HEIGHT / 5);
g.drawLine(WIDTH / 2, (int) (HEIGHT * (double) 105 / 400), WIDTH / 2, HEIGHT);
g.drawLine(0, HEIGHT / 5, WIDTH, HEIGHT / 5);
g.drawRect((int) (WIDTH * (double) 45 / 100), HEIGHT / 5, WIDTH / 10, (int) (HEIGHT * (double) 3 / 20));
g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
g.setFont(new Font("Times New Roman", Font.PLAIN, fontSize));
g.drawString("Errors", (int) (WIDTH * (double) 101 / 220), HEIGHT / 4);
}
private JFrame getFrame() {
return this;
}
public static void main(final String args[]) {
new ScoreFrame().setVisible(true);
}
public class EscapeListener implements KeyListener {
public void keyPressed(final KeyEvent event) {
if (event.getKeyCode() == 27) {
final int choice = JOptionPane.showConfirmDialog(getFrame(), "Do you want to exit the program?");
if (choice == 0) {
System.exit(0);
}
}
}
public void keyReleased(final KeyEvent event) {
}
public void keyTyped(final KeyEvent event) {
}
}
}
答案 0 :(得分:7)
调用pack()
是使用布局的关键步骤。此示例使用JLabel.CENTER
和GridLayout
在调整帧大小时使标签居中。为简单起见,中心面板只是一个占位符。这个稍微复杂的example使用了与java.text.MessageFormat
类似的方法。
附录:但我如何将 pack()
应用于我的代码?
只需调用pack()
,如引用的示例所示。我没有看到一种简单的方法来挽救你当前设定尺寸的方法。相反,请在JPanel
中覆盖主要内容中的getPreferredSize()
。无论屏幕尺寸如何,paintComponent()
的实施都应适应example的当前尺寸。
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
/** @see https://stackoverflow.com/a/14422016/230513 */
public class Scores {
private final JLabel[] nameLabel = new JLabel[]{
new JLabel("Team 1", JLabel.CENTER),
new JLabel("Team 2", JLabel.CENTER)};
private void display() {
JFrame f = new JFrame("Scores");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel teamPanel = new JPanel(new GridLayout(1, 0));
teamPanel.add(nameLabel[0]);
teamPanel.add(nameLabel[1]);
f.add(teamPanel, BorderLayout.NORTH);
f.add(new JPanel() {
@Override
public Dimension getPreferredSize() {
return new Dimension(320, 240);
}
}, BorderLayout.CENTER);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
new Scores().display();
}
});
}
}