Sort Columns

This chapter explains how to to sort the columns of the table ascending/descending.

Create a new Class "de.vogella.jface.tableviewer.sorter.TableSorter.java"

   
package de.vogella.jface.tableviewer.sorter;

import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerSorter;

import de.vogella.jface.tableviewer.model.Person;

public class TableSorter extends ViewerSorter {
 private int propertyIndex;
 // private static final int ASCENDING = 0;
 private static final int DESCENDING = 1;

 private int direction = DESCENDING;

 public TableSorter() {
  this.propertyIndex = 0;
  direction = DESCENDING;
 }

 public void setColumn(int column) {
  if (column == this.propertyIndex) {
   // Same column as last sort; toggle the direction
   direction = 1 - direction;
  } else {
   // New column; do an ascending sort
   this.propertyIndex = column;
   direction = DESCENDING;
  }
 }

 @Override
 public int compare(Viewer viewer, Object e1, Object e2) {
  Person p1 = (Person) e1;
  Person p2 = (Person) e2;
  int rc = 0;
  switch (propertyIndex) {
  case 0:
   rc = p1.getFirstName().compareTo(p2.getFirstName());
   break;
  case 1:
   rc = p1.getLastName().compareTo(p2.getLastName());
   break;
  case 2:
   rc = p1.getGender().compareTo(p2.getGender());
   break;
  case 3:
   if (p1.isMarried() == p2.isMarried()) {
    rc = 0;
   } else
    rc = (p1.isMarried() ? 1 : -1);
   break;
  default:
   rc = 0;
  }
  // If descending order, flip the direction
  if (direction == DESCENDING) {
   rc = -rc;
  }
  return rc;
 }
}
  

Add a listener to the view for setting the information which column should be sorted. Change View.java to the following-

   
package de.vogella.jface.tableviewer;

import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.jface.viewers.TableViewerColumn;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableColumn;
import org.eclipse.ui.part.ViewPart;

import de.vogella.jface.tableviewer.model.ModelProvider;
import de.vogella.jface.tableviewer.providers.PersonContentProvider;
import de.vogella.jface.tableviewer.providers.PersonEditingSupport;
import de.vogella.jface.tableviewer.providers.PersonLabelProvider;
import de.vogella.jface.tableviewer.sorter.TableSorter;

public class View extends ViewPart {
 public static final String ID = "de.vogella.jface.tableviewer.view";

 private TableViewer viewer;

 private TableSorter tableSorter;

 public void createPartControl(Composite parent) {
  createViewer(parent);
  // Get the content for the viewer, setInput will call getElements in the
  // contentProvider
  viewer.setInput(ModelProvider.getInstance().getPersons());
  // Make the selection available
  getSite().setSelectionProvider(viewer);
  // Set the sorter for the table
  tableSorter = new TableSorter();
  viewer.setSorter(tableSorter);

 }
 
 private void createViewer(Composite parent) {
  viewer = new TableViewer(parent, SWT.MULTI | SWT.H_SCROLL
    | SWT.V_SCROLL | SWT.FULL_SELECTION);
  createColumns(viewer);
  viewer.setContentProvider(new PersonContentProvider());
  viewer.setLabelProvider(new PersonLabelProvider());
 }

 public TableViewer getViewer() {
  return viewer;
 }

 // This will create the columns for the table
 private void createColumns(final TableViewer viewer) {
  Table table = viewer.getTable();
  String[] titles = { "First name", "Last name", "Gender", "Married" };
  int[] bounds = { 100, 100, 100, 100 };

  for (int i = 0; i < titles.length; i++) {
   final int index = i;
   final TableViewerColumn viewerColumn = new TableViewerColumn(
     viewer, SWT.NONE);
   final TableColumn column = viewerColumn.getColumn();
   column.setText(titles[i]);
   column.setWidth(bounds[i]);
   column.setResizable(true);
   column.setMoveable(true);
   // Setting the right sorter
   column.addSelectionListener(new SelectionAdapter() {
    @Override
    public void widgetSelected(SelectionEvent e) {
     tableSorter.setColumn(index);
     int dir = viewer.getTable().getSortDirection();
     if (viewer.getTable().getSortColumn() == column) {
      dir = dir == SWT.UP ? SWT.DOWN : SWT.UP;
     } else {

      dir = SWT.DOWN;
     }
     viewer.getTable().setSortDirection(dir);
     viewer.getTable().setSortColumn(column);
     viewer.refresh();
    }
   });
   viewerColumn.setEditingSupport(new PersonEditingSupport(viewer, i));
  }
  table.setHeaderVisible(true);
  table.setLinesVisible(true);
 }

 /**
  * Passing the focus request to the viewer's control.
  */
 public void setFocus() {
  viewer.getControl().setFocus();
 }
}
  

Run the example, click on a column, there will appear a sort-direction signifier and your items are ordered ascending or descending.