Question

I am making a dialog for the purpose of selecting multiple file paths. My dialog consists of two panels. One for buttons such as “Add” and “Remove”, and a second panel containing a JTable wrapped in a scrollPane. The table has only one column. The cells of the table are not editable directly. When a user selects a file using a JFileChooser, the full path of that file will be added to the table. Although my dialog is resizeable, I still need a horizontal scroll behavior in the event that the file path is longer than the user’s screen is wide.

I have researched the combination of resizeable table and horizontal scroll bar. That is similar, but not my issue. The typical scroll behavior is that the columns are scrolled, not the contents of the columns. I need the contents of a single column to scroll horizontally.

Answer 1

doesn’t matter whether you scroll a multiple or only a single column: the basic issue is to get the horizontal scrollBar to start with 🙂

There are two screws to tweak:
– enable horizontal scrolling by setting the table’s resizeMode: default is to always fit the table’s size to the size of the scrollPane, that is no scrolling
– resize the column width to fit its content

In a core JTable that maps into pseudo-code like

table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
// on receiving a TableModelEvent which might increase the column width
// calculate new width by measuring pref of the renderer
int newWidth = ... 
// set it as pref of the column 
table.getColumnModel().getColumn(0).setPreferredWidth(newWidth);

The catch is that without resizeMode, you are always responsible to sizing the column: it its width is less than the scrollPane, there’s an empty region at its trailing side.

JXTable (part of SwingX project), supports an addition sizing mode which fills the available horizontal space as long as the table’s prefWidts is less than parent width and shows a horizontal scrollBar if needed

table.setHorizontalScrollEnabled(true);
// on receiving a TableModelEvent which might increase the column width
// tell the table to re-evaluate 
table.packColumn(0);