如何更改JTable（JAVA）中特定单元格的颜色？

Question

well my question is how to change the color of a specific cell in a JTable in Java? as far as I know the first thing I should do is to override the method CellRendered I have already did this part as follows:

public class CustomTableCellRenderer extends DefaultTableCellRenderer 
{
    int amount;
    int f,c;

    public CustomTableCellRenderer(int a)
    {

        amount = a;


    }
    public CustomTableCellRenderer()
    {




    }
@Override
public Component getTableCellRendererComponent
   (JTable table, Object value, boolean isSelected,
   boolean hasFocus, int row, int column) 
   {
    Component cell = super.getTableCellRendererComponent
    (table, value, isSelected, hasFocus, row, column);
    if(amount == 3)
    {

            cell.setBackground(Color.LIGHT_GRAY);

    }
    if(amount == 1)
    {

        cell.setBackground(Color.cyan);

    }
    if(amount == 2)
    {

        cell.setBackground(Color.orange);

    }


    return cell;
 }

}

And when I want to change the color of the cell, I change the color but it changes the whole column, the part of the code where I used the override goes as follows:

 Cache_table.getColumnModel().getColumn(columna).setCellRenderer(new    CustomTableCellRenderer(1));

How can I specify the exact position of the cell I want to change the color, specifying the number of row and column:

Eg:

new CustomTableCellRenderer(int row, int column);

Is that possible?

Thanks guys¡¡

Answer 1

Consider using else if statements and then adding a default value in the default last else block.

Also, and this is key , don't set amount in the renderer's constructor -- that won't work. Instead you must get the amount result inside of the getTableCellRendererComponent method, usually from the cell's value, or from the value from another model cell on the same row.

@Override
public Component getTableCellRendererComponent
   (JTable table, Object value, boolean isSelected,
   boolean hasFocus, int row, int column) {

    Component cell = super.getTableCellRendererCo

    // check that we're in the right column
    if (column != correctColumn) { 
        // if not the right column, don't change cell
        return cell;       
    }

    // SomeType is the type of object held in the correct column
    SomeType someType = (SomeType) value;

    if (value == null) {
        value = "";
        return cell;       
    }

    // and hopefully it has a method for getting the amount of interest
    int amount = someType.getAmount();

    if(amount == 3) {
            cell.setBackground(Color.LIGHT_GRAY);
    } else if(amount == 1) {
        cell.setBackground(Color.cyan);
    } else if(amount == 2) {
        cell.setBackground(Color.orange);
    } else {
        cell.setBackground(null); // or a default background color
    }

Also, you might need to be sure that your cell is opaque.