Question

My use case is as follows —
I have a list(ArrayList) of objects, custom data objects.
Now i want to display or represent each of these data objects as a Box containing 3 buttons. So i would have n Boxes for n given data objects in my list.

I want each of these ‘boxes’ to be stacked in a , say, JTable.

Now, whenever a data object is added to the aforementioned list, i want another Box to be created as mentioned before and added to the JTable.

I know this can be accomplished using PropertyChangeListener but i went through some articles online regarding PropertyChangeListener but was not able to get a clear implementable idea.

im new to building UIs and any help with this would be much appreciated.

Answer 1

I would recommend wrapping your ArrayList within a TableModel implementation, whereby modifications to the list will fire a TableModelEvent.

In the example below the underlying List is encapsulated within the model implementation; the only way to modify it is by calling addItem, which will call fireTableRowsInserted after modifying the list. This will result in a TableModelEvent being fired and subsequently processed by the JTable view onto this model instance.

public class MyTableModel extends AbstractTableModel {
  private final List<MyItem> items = new ArrayList<MyItem>();

  public int getRowCount() {
    return items.size();
  }

  public int getColumnCount() {
    return 3;
  }

  public String getColumnName(int columnIndex) {
    switch(columnIndex) {
      case 0:
        return "foo";
      case 1:
        return "bar";
      case 2:
        return "qux";
      default:
        assert false : "Invalid column index: " + columnIndex;
    }
  }

  public void addItem(MyItem item) {
    items.add(item);
    fireTableRowsInserted(items.size() - 1, items.size() - 1);
  }
}