import org.eclipse.jface.viewers.ITreeViewerListener;
import org.eclipse.jface.viewers.TreeExpansionEvent;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.swt.widgets.TreeColumn;

public class TreeColumnAutoSizeListener implements ITreeViewerListener {

    /**
     * 节点展开事件.
     */
    public void treeExpanded(TreeExpansionEvent event) {
        packColumns((TreeViewer) event.getSource());
    }

    /**
     * 节点折叠事件.
     */
    public void treeCollapsed(TreeExpansionEvent event) {
        packColumns((TreeViewer) event.getSource());
    }

    /**
     * 自动包装列宽度.
     * 
     * @param treeViewer
     *            TreeViewer
     */
    private void packColumns(final TreeViewer treeViewer) {
        // 更新界面，要异步执行
        treeViewer.getControl().getShell().getDisplay()
                .asyncExec(new Runnable() {
                    public void run() {
                        TreeColumn[] treeColumns = treeViewer.getTree()
                                .getColumns();
                        for (TreeColumn treeColumn : treeColumns) {
                            if (treeColumn.getWidth() == 0)
                                continue;

                            treeColumn.pack();
                        }
                    }
                });
    }
}