JTable not showing

问题:

In my application everything is distributed.

• On a action, application retrieves data from DB and saves in ArrayList<T>.

• I create an object of RelativeTableModel where I pass the ArrayList<T>.

  public void RelationsClicked() {
      ArrayList<Relation> data = myParent.dbOperation.getRelations();
      RelativeTableModel tModel = new RelativeTableModel(data);  // subclass of AbstractTableModel
      myParent.SetBrowsePanelData(tModel);
      myParent.SetMainPanel(CashAccountingView.BROWSEPANEL);
  }
  

  • I have a BrowseListPanel class that has a JTable in JScrollPane. Its instance is already created in the main application.
  • I pass the model to BrowseListPanel and finally show the panel.

Code:

public void SetBrowsePanelData(AbstractTableModel tModel) {
    browsePanel.setTModel(tModel);
}

// BrowseListPanel's Code
public void setTModel(AbstractTableModel tModel) {
    this.tModel = tModel;  // tModel = AbstractTableModel
}

// Show the Panel
public void SetMainPanel(String panel) {
    activePanel = panel;
    SetFontSize();
    cards.show(mainPanel, panel);
    mainPanel.revalidate();
    mainPanel.repaint();
}

But I don't see the Table. I believe as the object of BrowseListPanel (containing the JTable) is already created & later the TableModel is added. So some sort of event should be fired in setTModel().

Am I right? If so, what event should be thrown and what should be its implementation.

回答1:

Invoking setModel() on the table should be sufficient, but you might call fireTableStructureChanged() on the model explicitly as a way to help sort things out.

Also, verify that you are working on the event dispatch thread.

Addendum: Here's an sscce that shows the basic approach.

import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;

/** @see http://stackoverflow.com/questions/8257148 */
public class SwapTableModel extends JPanel {

    public SwapTableModel() {
        final JTable table = new JTable(Model.Alpha.model);
        table.setPreferredScrollableViewportSize(new Dimension(128, 32));
        this.add(new JScrollPane(table));
        final JComboBox combo = new JComboBox();
        for (Model model : Model.values()) {
            combo.addItem(model);
        }
        this.add(combo);
        combo.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                Model model = (Model) combo.getSelectedItem();
                table.setModel(model.model);
            }
        });
    }

    private enum Model {

        Alpha(), Beta();
        private DefaultTableModel model;

        private Model() {
            Object[] data = {this.toString()};
            this.model = new DefaultTableModel(data, 1);
            model.addRow(data);
        }
    }

    private void display() {
        JFrame f = new JFrame("SwapTableModel");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(this);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                new SwapTableModel().display();
            }
        });
    }
}