Modify text alignment in a JTable cell

Question

I have found a way to allocate the cell in a table, which seems to be a Component

JTable table = new JTable(...)
{
    public Component prepareRenderer(
        TableCellRenderer renderer, int row, int column)
    {
        Component c = super.prepareRenderer(renderer, row, column);

        //  add custom rendering here

        return c;
    }
};

In the code, c is the Component, but I cannot find a method in Component to modify text alignment. Anything wrong about this approach?

Answer 1

Use DefaultTableCellRenderer for that purposes, it has setHorizontalAlignment() method :

DefaultTableCellRenderer renderer = new DefaultTableCellRenderer(){
    @Override
    public Component getTableCellRendererComponent(JTable arg0,Object arg1, boolean arg2, boolean arg3, int arg4, int arg5) {
         Component tableCellRendererComponent = super.getTableCellRendererComponent(arg0, arg1, arg2, arg3, arg4, arg5);
         int align = DefaultTableCellRenderer.CENTER;
         if(condition){
             align = DefaultTableCellRenderer.LEFT;
         }
        ((DefaultTableCellRenderer)tableCellRendererComponent).setHorizontalAlignment(align);
         return tableCellRendererComponent;
    }
};
t.getColumnModel().getColumn(COLUMN).setCellRenderer(renderer);

COLUMN is target column, condition is condition for switching.

Answer 2

(J)Component havent this method(s) implemented in API

there are two ways

1. by casting (J)Component to JLabel

2. set this value for class managed by getColumnClass

.

DefaultTableCellRenderer stringRenderer = (DefaultTableCellRenderer)
     table.getDefaultRenderer(String.class);
stringRenderer.setHorizontalAlignment(SwingConstants.CENTER);

Answer 3

I am going to make a conclusion.

For this specifiec problem, we can divide it into two:

1. allocate the cell
2. agjust its alignment

To allocate the cell, my originally way and the way alex2410 should be both useful.

JTable table = new JTable(...)
{
    public Component prepareRenderer(
        TableCellRenderer renderer, int row, int column)
    {
        Component c = super.prepareRenderer(renderer, row, column);

        //  add custom rendering here

        return c;
    }
};

another

DefaultTableCellRenderer renderer = new DefaultTableCellRenderer(){
    @Override
    public Component getTableCellRendererComponent(
             JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
         Component c = super.getTableCellRendererComponent(arg0, arg1, arg2, arg3, arg4, arg5);

         //  add custom rendering here

         return c;
    }
};
t.getColumnModel().getColumn(COLUMN).setCellRenderer(renderer);

And for alignment, the only method I found useful is:

((DefaultTableCellRenderer)c).setHorizontalAlignment(SwingConstants.center);

In mKorbel's suggestion, you can cast the Component c to JLabel , but I failed to to that.