Question

I would like to highlight specific rows in a JTable whenever the contents of the a cell match with an input from the user. The following code is what I have that works thus far:

JTable table = new JTable(model) {
    public Component prepareRenderer(
            TableCellRenderer renderer, int row,
            int column) {
        Component c = super.prepareRenderer(renderer,
                row, column);
        if (!isRowSelected(row) ) {
            c.setBackground((hashMapcontainer
                    .containsKey(row)) ? Color.GREEN
                    : getBackground());
        }
        return c;
    }
    @Override
    public boolean isCellEditable(int row, int column) {
        return false;
    }
};

Notes: hashMapcontainer is a hashmap that is globally scoped within the source file.

Now this works to some extent however, I am adding this JTable to a JTabbedPane that is within a JFrame. JTables are dynamically created throughout the runtime of the program. However, the prepareRenderer method causes all the specific cells in all the created JTables to be highlighted.

How can I keep cells in all the JTables to keep their own specific highlighted cells rather than having all the JTables with the same exact highlighted cells in each?

Thanks in advance!

Answer 1

The renderers are “rubber stamps”. That basically means that they carry there previous settings over to the next cell.

What you need to do is provide a “default” behavior

if (!isRowSelected(row) ) {
    c.setBackground((hashMapcontainer
        .containsKey(row)) ? Color.GREEN
        : getBackground());
} else {

    // Define the default background color
    // Don't forget to take into the selection state

}

While I personally think that prepareRenderer in this case is probably a fair solution, you really should explore the possibly of providing a base line renderer. This is a lot of work to get right but has the advantage of been portable (if you change table implementations) as well as allowing other
people the chance to define the highlight rules of a given cell, which you’ve basically just gone and overridden, IMHO.

I’d also suggest taking a look at JXTable as it has in built highlighting