距离JPanel顶部的距离越来越远

Question

我正在尝试增加我的JButtons从我的面板顶部的距离，使其更具视觉吸引力，我尝试使用隐形按钮，但没有运气。

public class SimpleBorder {

public static void main(String[] args) {

    JFrame frame = new JFrame();
    frame.setSize(500,500);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);       

    Border etched = (Border) BorderFactory.createEtchedBorder();


    String[] items = {"A", "B", "C", "D"};
    JList list = new JList(items);

    JTextArea text = new JTextArea(10, 40);

    JScrollPane scrol = new JScrollPane(text);
    JScrollPane scrol2 = new JScrollPane(list);

    JPanel panel= new JPanel();
    panel.add(scrol2,BorderLayout.WEST);
    panel.add(scrol, BorderLayout.EAST);    
    panel.setBorder(etched);

    frame.add(panel);
    frame.setVisible(true);
}

}

有什么想法吗？

Answer 1

事实上，关键基本上在于组件不知道它的实际大小，直到frame.pack()不会被调用。因此，在此之后，我执行此计算，以确定Border为frame.pack()添加多少空白空间，并在放置repack()之后再次调用Border到import java.awt.*; import javax.swing.*; public class MainMenu { private JButton playButton; private JButton instructionButton; private JButton scoreboardButton; private JButton exitButton; private JPanel menuPanel; private GridBagConstraints gbc; public MainMenu() { gbc = new GridBagConstraints(); gbc.insets = new Insets(15, 15, 15, 15); gbc.anchor = GridBagConstraints.FIRST_LINE_START; } private void displayGUI() { JFrame frame = new JFrame("Main Menu"); frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); JPanel contentPane = new JPanel(new BorderLayout()); menuPanel = new JPanel(new GridBagLayout()); menuPanel.setOpaque(true); menuPanel.setBackground(Color.BLACK); playButton = new JButton("Play"); instructionButton = new JButton("Instructions"); scoreboardButton = new JButton("Scoreboard"); exitButton = new JButton("Exit"); addComp(menuPanel, playButton, 0, 0, 1, 1, 1.0, 0.20, GridBagConstraints.HORIZONTAL); addComp(menuPanel, instructionButton, 0, 1, 1, 1, 1.0, 0.20, GridBagConstraints.HORIZONTAL); addComp(menuPanel, scoreboardButton, 0, 2, 1, 1, 1.0, 0.20, GridBagConstraints.HORIZONTAL); addComp(menuPanel, exitButton, 0, 3, 1, 1, 1.0, 0.20, GridBagConstraints.HORIZONTAL); contentPane.add(menuPanel); frame.setContentPane(contentPane); frame.pack(); contentPane.setBorder( BorderFactory.createEmptyBorder( contentPane.getHeight() - (contentPane.getHeight() / 4), 20, 5, 20)); frame.pack(); frame.setLocationByPlatform(true); frame.setVisible(true); } private void addComp(JPanel panel, JComponent comp, int gridx, int gridy, int gridwidth, int gridheight, double weightx, double weighty, int fill) { gbc.gridx = gridx; gbc.gridy = gridy; gbc.gridwidth = gridwidth; gbc.gridheight = gridheight; gbc.weightx = weightx; gbc.weighty = weighty; gbc.fill = fill; panel.add(comp, gbc); } public static void main(String[] args) { Runnable runnable = new Runnable() { @Override public void run() { new MainMenu().displayGUI(); } }; EventQueue.invokeLater(runnable); } } 。

请看一下这个例子，看看这个套件是否符合您的需求：

GridLayout

这是输出：

编辑1：

此外，如果您使用GridBagLayout代替MainMenu使用import java.awt.*; import javax.swing.*; public class MainMenu { private JButton playButton; private JButton instructionButton; private JButton scoreboardButton; private JButton exitButton; private JPanel menuPanel; private void displayGUI() { JFrame frame = new JFrame("Main Menu"); frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); JPanel contentPane = new JPanel(new GridBagLayout()); menuPanel = new JPanel(new GridLayout(0, 1, 5, 5)); menuPanel.setBorder( BorderFactory.createEmptyBorder(5, 5, 5, 5)); menuPanel.setOpaque(true); menuPanel.setBackground(Color.BLACK); playButton = new JButton("Play"); instructionButton = new JButton("Instructions"); scoreboardButton = new JButton("Scoreboard"); exitButton = new JButton("Exit"); menuPanel.add(playButton); menuPanel.add(instructionButton); menuPanel.add(scoreboardButton); menuPanel.add(exitButton); contentPane.add(menuPanel); frame.setContentPane(contentPane); frame.pack(); contentPane.setBorder( BorderFactory.createEmptyBorder( contentPane.getHeight() - (contentPane.getHeight() - (3 * menuPanel.getHeight())), 20, 0, 20)); frame.pack(); frame.setLocationByPlatform(true); frame.setVisible(true); } public static void main(String[] args) { Runnable runnable = new Runnable() { @Override public void run() { new MainMenu().displayGUI(); } }; EventQueue.invokeLater(runnable); } } ，那么我猜结果会更有希望。请查看此示例以了解该更改：

JPanel

编辑2：

另一种变体看起来要好得多，但这一次，基础GridLayout正在使用MenuPanel而GridBagLayout正在使用import java.awt.*; import javax.swing.*; public class MainMenu { private JButton playButton; private JButton instructionButton; private JButton scoreboardButton; private JButton exitButton; private JPanel menuPanel; private GridBagConstraints gbc; public MainMenu() { gbc = new GridBagConstraints(); gbc.insets = new Insets(15, 15, 15, 15); gbc.anchor = GridBagConstraints.CENTER; } private void displayGUI() { JFrame frame = new JFrame("Main Menu"); frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); JPanel contentPane = new JPanel(new GridLayout(1, 1, 5, 2)); menuPanel = new JPanel(new GridBagLayout()); menuPanel.setBorder( BorderFactory.createEmptyBorder(5, 5, 5, 5)); menuPanel.setOpaque(true); menuPanel.setBackground(Color.BLACK); playButton = new JButton("Play"); instructionButton = new JButton("Instructions"); scoreboardButton = new JButton("Scoreboard"); exitButton = new JButton("Exit"); addComp(menuPanel, playButton, 0, 0, 1, 1, 1.0, 0.10, GridBagConstraints.CENTER); addComp(menuPanel, instructionButton, 0, 1, 1, 1, 1.0, 0.10, GridBagConstraints.CENTER); addComp(menuPanel, scoreboardButton, 0, 2, 1, 1, 1.0, 0.10, GridBagConstraints.CENTER); addComp(menuPanel, exitButton, 0, 3, 1, 1, 1.0, 0.10, GridBagConstraints.CENTER); contentPane.add(menuPanel); frame.setContentPane(contentPane); frame.pack(); contentPane.setBorder( BorderFactory.createEmptyBorder( contentPane.getHeight() - (contentPane.getHeight() - (2 * menuPanel.getHeight()) + 100), 20, 2, 20)); frame.pack(); frame.setLocationByPlatform(true); frame.setVisible(true); } private void addComp(JPanel panel, JComponent comp, int gridx, int gridy, int gridwidth, int gridheight, double weightx, double weighty, int fill) { gbc.gridx = gridx; gbc.gridy = gridy; gbc.gridwidth = gridwidth; gbc.gridheight = gridheight; gbc.weightx = weightx; gbc.weighty = weighty; gbc.fill = fill; panel.add(comp, gbc); } public static void main(String[] args) { Runnable runnable = new Runnable() { @Override public void run() { new MainMenu().displayGUI(); } }; EventQueue.invokeLater(runnable); } } 。请看一下这个例子：

{{1}}