Verify that you can start your application like that: java -cp myjarfile.jar snake.Controller I just read when I double click on it – this sounds like a configuration issue with your operating system. You’re double-clicking the file on a windows explorer window? Try to run it from a console/terminal with the command java -jar myjarfile.jar … Read more
The documentation tells me, that this behavior is platform dependent. Especially, since the following example code works for me as desired in Windows Vista: import java.awt.Dimension; import javax.swing.JFrame; public class JFrameExample { public static void main(String[] args) { JFrame frame = new JFrame(“Hello World”); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setMinimumSize(new Dimension(100, 100)); frame.setVisible(true); } }
No, you can’t add components at a specific cell. What you can do is add empty JPanel objects and hold on to references to them in an array, then add components to them in any order you want. Something like: int i = 3; int j = 4; JPanel[][] panelHolder = new JPanel[i][j]; setLayout(new GridLayout(i,j)); … Read more
Essentially, you’re going to need to supply a “renderer” for the tab. Take a look at JTabbedPane.setTabComponentAt(…) for more information. The basic idea is to supply a component that will be laid out on the tab. I typically create a JPanel, onto which I add a JLabel (for the title) and, depending on what I … Read more
Thoughts: Avoid extending JFrame as it ties your GUI to being, well a JFrame. If instead you concentrate on creating JPanels instead, then you have the freedom to use these JPanels anywhere needed — in a JFrame, or JDialog, or JApplet, or inside of another JPanel, or swapped with other JPanels via a CardLayout. Avoid … Read more
For that, you need to use ActionListener, for example: JButton b = new JButton(“push me”); b.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { //your actions } }); For generating click event programmatically, you can use doClick() method of JButton: b.doClick();
You need to customize the renderer. To center the first column you can do: DefaultTableCellRenderer centerRenderer = new DefaultTableCellRenderer(); centerRenderer.setHorizontalAlignment( JLabel.CENTER ); table.getColumnModel().getColumn(0).setCellRenderer( centerRenderer ); To center all columns with String data you can do: DefaultTableCellRenderer centerRenderer = new DefaultTableCellRenderer(); centerRenderer.setHorizontalAlignment( JLabel.CENTER ); table.setDefaultRenderer(String.class, centerRenderer);
Set GridBagLayout for JPanel, put JLabel without any GridBagConstraints to the JPanel, JLabel will be centered example import java.awt.*; import javax.swing.*; public class CenteredJLabel { private JFrame frame = new JFrame(“Test”); private JPanel panel = new JPanel(); private JLabel label = new JLabel(“CenteredJLabel”); public CenteredJLabel() { panel.setLayout(new GridBagLayout()); panel.add(label); panel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10)); frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); frame.add(panel); … Read more
The problem is that the height of rows in JTable is fixed, so it’s not just a matter of having a renderer that wraps; I’m not sure why it doesn’t, but if it did, the wrapped text would be cropped – or maybe that’s exactly what you’re seeing. To adjust row heights, you need to … Read more
I believe the only way to do this with the public API is to write a custom UI (there are two bugs dealing with this). If you just want something quick-and-dirty, I found this way to use implementation details to do it (here): public void popupMenuWillBecomeVisible(PopupMenuEvent e) { JComboBox box = (JComboBox) e.getSource(); Object comp … Read more