Java-JScrollPane与JTable不对齐

Question

I am trying to make a JTable that has a width of 500. The problem is that the JScrollPane associated with the table doesn't appear next to the table.

Here is the relevant code:

    // Create authorsPanel
    JPanel authorsPanel = new JPanel(new BorderLayout(5,5));
    authorsPanel.setBorder( new TitledBorder("Author Selection") );

    // Configure author table
    DefaultTableModel authorstableModel = new DefaultTableModel(new String[80][1], new String[]{"Authors"}) {
        @Override
        public boolean isCellEditable(int row, int column) {
           //all cells false
           return false;
        }
    };
    JTable authorsTable = new JTable(authorstableModel);
    authorsTable.getColumnModel().getColumn(0).setPreferredWidth(500);
    authorsTable.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
    try {
        authorsTable.setAutoCreateRowSorter(true);
    } catch(Exception continuewithNoSort) {
    }
    JScrollPane tableScroll = new JScrollPane(authorsTable);
    Dimension tablePreferred = tableScroll.getPreferredSize();
    tableScroll.setPreferredSize(new Dimension(500, tablePreferred.height/3));
    authorsPanel.add(tableScroll);

Here is a screenshot:

When I get rid of the line:

authorsTable.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);

Then the table returns to being the full width of the panel, so it seems like I need this line.

Answer 1

The java docs on BorderLayout states :

The components are laid out according to their preferred sizes and the constraints of the container's size. The NORTH and SOUTH components may be stretched horizontally; the EAST and WEST components may be stretched vertically; the CENTER component may stretch both horizontally and vertically to fill any space left over.

You have used authorsPanel.add(tableScroll) to add the JScrollPane to the JPanel . So you are basically adding it to the center . So this is going to occupy the whole space that is lying vacant.

The solution to your problem lies in choosing a different layout. I could suggest MigLayout which is very versatile and you can get all kinds of effects using it.

Answer 2

You add your scroll pane to a panel with BorderLayout. BorderLayout does not care about preferred size. Use eg GridBagLayout with proper constraints or you can BoxLayout (with horizontal flow) placing the table first and an empty panel second as place holder.