JTable Scrolling to a Specified Row Index

Question

I have a JTable that is within a JScrollPane. Rows are added to the table at runtime based on events that happen in my application. I want to have the scoll pane scroll to the bottom of the table when a new row is added to the table.

For JLists There is the [ensureIndexIsVisible][1]() that forces a particular index in the list to be visible. I'm looking for the same thing but for a JTable. It looks like I might have to manually move the scrolling view on the scroll pane but I figured there had to be an easier way.

Answer 1

See this example : http://www.exampledepot.com/egs/javax.swing.table/Vis.html

update: the link is now obsolete, here is the code (from http://smi-protege.stanford.edu/repos/protege/protege-core/trunk/src/edu/stanford/smi/protege/util/ComponentUtilities.java )

public static void scrollToVisible(JTable table, int rowIndex, int vColIndex) {
        if (!(table.getParent() instanceof JViewport)) {
            return;
        }
        JViewport viewport = (JViewport)table.getParent();

        // This rectangle is relative to the table where the
        // northwest corner of cell (0,0) is always (0,0).
        Rectangle rect = table.getCellRect(rowIndex, vColIndex, true);

        // The location of the viewport relative to the table
        Point pt = viewport.getViewPosition();

        // Translate the cell location so that it is relative
        // to the view, assuming the northwest corner of the
        // view is (0,0)
        rect.setLocation(rect.x-pt.x, rect.y-pt.y);

        table.scrollRectToVisible(rect);

        // Scroll the area into view
        //viewport.scrollRectToVisible(rect);
    }

Answer 2

It's very easy, JTable has scrollRectToVisible method too. If you want, you can try something like this to make scrollpane go to to the bottom if a new record is added :

jTable1.getSelectionModel().setSelectionInterval(i, i);
jTable1.scrollRectToVisible(new Rectangle(jTable1.getCellRect(i, 0, true)));

Where i is last added record.

Answer 3

JList internally use scrollRectToVisible and specify the coordinates to scroll to. I think you will have to recode a similar functionality for JTable.

Answer 4

The first answer works well, but the selected row gets positioned at the bottom of the table. So I created this modified version:

private void scrollToVisible(int rowIndex, int vColIndex ) {
        JTable table = getTablePanel().getTable();
        if (!(table.getParent() instanceof JViewport)) {
            return;
        }
        if (table.getRowCount()<1){
            return;
        }
        JViewport viewport = (JViewport)table.getParent();
        // view dimension
        Dimension dim = viewport.getExtentSize();
        // cell dimension
        Dimension dimOne = new Dimension(0,0);

        // This rectangle is relative to the table where the
        // northwest corner of cell (0,0) is always (0,0).
        Rectangle rect = table.getCellRect(rowIndex, vColIndex, true);
        Rectangle rectOne;
        if (rowIndex+1<table.getRowCount()) {
            if (vColIndex+1<table.getColumnCount())
                vColIndex++;
            rectOne = table.getCellRect(rowIndex+1, vColIndex, true);
            dimOne.width=rectOne.x-rect.x;
            dimOne.height=rectOne.y-rect.y;
        }

        // '+ veiw dimension - cell dimension' to set first selected row on the top

        rect.setLocation(rect.x+dim.width-dimOne.width, rect.y+dim.height-dimOne.height);

        table.scrollRectToVisible(rect);
    }

Now the selected row gets positioned at the top of the table.

Answer 5

It seems to me a lot easier to set the viewport position instead of scrolling the table. Following is my code.

public void scrollCellToView(int rowIndex, int vColIndex) {
    if (!(this.getParent() instanceof JViewport)) {
        return;
    }
    JViewport viewport = (JViewport) this.getParent();
    Rectangle rect = this.getCellRect(rowIndex, vColIndex, true);
    Rectangle viewRect = viewport.getViewRect();

    int x = viewRect.x;
    int y = viewRect.y;

    if (rect.x >= viewRect.x && rect.x <= (viewRect.x + viewRect.width - rect.width)){

    } else if (rect.x < viewRect.x){
        x = rect.x;
    } else if (rect.x > (viewRect.x + viewRect.width - rect.width)) {
        x = rect.x - viewRect.width + rect.width;
    }

    if (rect.y >= viewRect.y && rect.y <= (viewRect.y + viewRect.height - rect.height)){

    } else if (rect.y < viewRect.y){
        y = rect.y;
    } else if (rect.y > (viewRect.y + viewRect.height - rect.height)){
        y = rect.y - viewRect.height + rect.height;
    }

    viewport.setViewPosition(new Point(x,y));
}