Change background color of JTable whole row based on column value

Question

So what I am trying to do, is to change the color of each row based on values inside of the last column.

I already found this solution: Change Background Color of JTable which worked very well.

But in addition I want to switch the color of the row to green when the fourth column reaches the same value as the second one.

I used the approach of Cristian Marian and wrote my own class

    @Override
public Component prepareRenderer(TableCellRenderer renderer, int row, int column) {
    Component comp = super.prepareRenderer(renderer, row, column);


        int second = (int) this.getModel().getValueAt(row, 1);
        int forth = (int) this.getModel().getValueAt(row, 3);
        int kat = Kategorie.getNumber((String) this.getModel().getValueAt(row, 2)); 
        if (kat > 0) {
            if (second == forth) {
                comp.setBackground(Color.GREEN);
            } else {
                comp.setBackground(Color.RED);
            }
        }

    return comp;
}

Still only the last cell in each column changes to green instead of the whole one. But when I clock on the row, the whole row switches the color

The values in the last column are changed by another frame.

Table at the beginning:

When the value in the last column reaches the same value as in the second one it looks like this:

After reaching the given value:

Answer 1

The problem with your approach is that you use getTableCellRendererComponent so only that cell will have its color changed.

I had to make something similar. Based on the value of a column, I had to color the row.

I used a class that extended the JTable and Override prepareRenderer

@Override
public Component prepareRenderer(TableCellRenderer renderer, int row, int column) {
    Component comp = super.prepareRenderer(renderer, row, column);
    if (populated) {  //this if was just to make sure that I have data in my table
        /*
        *This piece makes the code ignore the rows that are selected as this approach messes up that blue color that selected rows get
        */
        int[] rows = this.getSelectedRows();
        boolean rowisSelected = false;

        for (int rowIndex : rows) {
            if (row == rowIndex) {
                rowisSelected = true;
                break;
            }
        }
        /*
        *And this is the part that does the coloring
        */
        if (!rowisSelected) {
            Integer status = Integer.parseInt((String) 
            int modelRow = convertRowIndexToModel(row);
            this.getModel().getValueAt(modelRow, Constants.HIDDEN_COLUMN));
            switch (status) {
            case 1:
                comp.setForeground(Color.BLACK);
                comp.setBackground(Color.WHITE);
                break;
            case 2:
                comp.setForeground(Color.LIGHT_GRAY);
                comp.setBackground(Color.WHITE);
                break;
            case 3:
                comp.setForeground(Color.BLACK);
                comp.setBackground(Constants.DOWNLOADED_COLOR);
                break;
            case 4:
                comp.setForeground(Color.LIGHT_GRAY);
                comp.setBackground(Constants.DOWNLOADED_COLOR);
                break;
            }
        }
    }
    return comp;
}

Yours should be something like this (without the selected row thing):

@Override
public Component prepareRenderer(TableCellRenderer renderer, int row, int column) {
    Component comp = super.prepareRenderer(renderer, row, column);
    int modelRow = convertRowIndexToModel(row);
    String second = this.getModel().getValueAt(modelRow, 1));
    String forth= this.getModel().getValueAt(modelRow, 3));
    if(second.equals(forth)){
        comp.setBackground(Color.GREEN);
    }
    return comp;
}