How to use

addSelectionChangedListener

method

in

org.eclipse.jface.text.TextViewer

/**
 * @param viewers All viewers that can provide a selection
 * @param viewerInFocus the viewer currently in focus or <code>null</code>
 */
public void setViewers(TextViewer[] viewers, TextViewer viewerInFocus) {
  Assert.isNotNull(viewers);
  fViewers= viewers;
  InternalListener listener= new InternalListener();
  fViewerInFocus= viewerInFocus;
  for (int i= 0; i < fViewers.length; i++) {
    TextViewer viewer= fViewers[i];
    viewer.addSelectionChangedListener(listener);
    viewer.addPostSelectionChangedListener(new InternalPostSelectionListener());
    StyledText textWidget = viewer.getTextWidget();
    textWidget.addFocusListener(listener);
  }
}

public void install(final TextViewer viewer, boolean spellCheck) {
  viewer.getControl().addFocusListener(new TextViewerFocusListener(viewer, spellCheck));
  if (selectionChangedListener != null) {
    viewer.addSelectionChangedListener(selectionChangedListener);
  }
  setTextViewer(viewer.getControl(), viewer);
}