Swt/Jface tableViewer入门教程二（让TableViewer按照列排序)

 有一个功能是我们常使用的，就是在列的头上点击一下，整个表的记录按照这个列来排序，再点击一下按照这个列的反序来排序。那JFace是如何实现这个功能的呢？
在JFace中是通过一个排序器来实现的，就是ViewerSorter下边写出详细的步骤
一、定义一个sorter继承自ViewerSorter

import  java.util.Date;

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

public   class  Sorter  extends  ViewerSorter  {
        private static final int ID = 1;
        private static final int NAME = 2;
        private static final int SEX = 3;
        private static final int AGE = 4;
        private static final int CREATE_DATE = 5;
        
        public static final Sorter ID_ASC = new Sorter(ID);
        public static final Sorter ID_DESC = new Sorter(-ID);
        public static final Sorter NAME_ASC = new Sorter(NAME);
        public static final Sorter NAME_DESC = new Sorter(-NAME);
        public static final Sorter SEX_ASC = new Sorter(SEX);
        public static final Sorter SEX_DESC = new Sorter(-SEX);
        public static final Sorter AGE_ASC = new Sorter(AGE);
        public static final Sorter AGE_DESC = new Sorter(-AGE);
        public static final Sorter CREATE_DATE_ASC = new Sorter(CREATE_DATE);
        public static final Sorter CREATE_DATE_DESC = new Sorter(-CREATE_DATE);
        
        private int sortType ;
        private Sorter(int sortType){
            this.sortType = sortType;
        }
        public int compare(Viewer viewer, Object e1, Object e2) {
            People p1 = (People)e1;
            People p2 = (People)e2;
            switch(sortType){
                case ID:{
                    Long l1 = p1.getId();
                    Long l2 = p2.getId();
                    return l1.compareTo(l2);
                }
                case -ID:{
                    Long l1 = p1.getId();
                    Long l2 = p2.getId();
                    return l2.compareTo(l1);
                }
                case NAME:{
                    String s1 = p1.getName();
                    String s2 = p2.getName();
                    return s1.compareTo(s2);
                }
                case -NAME:{
                    String s1 = p1.getName();
                    String s2 = p2.getName();
                    return s2.compareTo(s1);
                }
                case SEX:{
                    String s1 = p1.getSex();
                    String s2 = p2.getSex();
                    return s1.compareTo(s2);
                }
                case -SEX:{
                    String s1 = p1.getSex();
                    String s2 = p2.getSex();
                    return s2.compareTo(s1);
                }
                case AGE:{
                    Integer i1 = p1.getAge();
                    Integer i2 = p2.getAge();
                    return i1.compareTo(i2);
                }
                case -AGE:{
                    Integer i1 = p1.getAge();
                    Integer i2 = p2.getAge();
                    return i2.compareTo(i1);
                }
                case CREATE_DATE:{
                    Date d1 = p1.getCreateDate();
                    Date d2 = p2.getCreateDate();
                    d1.compareTo(d2);
                }
                case -CREATE_DATE:{
                    Date d1 = p1.getCreateDate();
                    Date d2 = p2.getCreateDate();
                    d2.compareTo(d1);
                }
            }
            return 0;
        }
    }

二、在TableViewer上，为每一列加入事件监听器类似这样的结构

    newColumnTableColumn.addSelectionListener( new  SelectionAdapter() {
            boolean asc = true;
            public void widgetSelected(SelectionEvent e){
                tableViewer.setSorter(asc?Sorter.ID_ASC:Sorter.ID_DESC);
                asc = !asc;
            }
        } );

都加入后TestTableViewer的结果：

import  org.eclipse.jface.viewers.TableViewer;
import  org.eclipse.swt.SWT;
import  org.eclipse.swt.events.SelectionAdapter;
import  org.eclipse.swt.events.SelectionEvent;
import  org.eclipse.swt.layout.FillLayout;
import  org.eclipse.swt.widgets.Display;
import  org.eclipse.swt.widgets.Shell;
import  org.eclipse.swt.widgets.Table;
import  org.eclipse.swt.widgets.TableColumn;

public   class  TestTableViewer  {
    private static Table table;
    /** *//**
     * Launch the application
     * @param args
     */
    public static void main(String[] args) {
        final Display display = Display.getDefault();
        final Shell shell = new Shell();
        shell.setSize(500, 375);
        shell.setText("SWT Application");
        //
        final TableViewer tableViewer = new TableViewer(shell, SWT.CHECK|SWT.MULTI | SWT.FULL_SELECTION | SWT.BORDER|SWT.V_SCROLL|SWT.H_SCROLL);
        
        table = tableViewer.getTable();
        table.setLinesVisible(true);
        table.setHeaderVisible(true);
        table.setBounds(97, 79, 373, 154);

        final TableColumn newColumnTableColumn = new TableColumn(table, SWT.NONE);
        newColumnTableColumn.setWidth(39);
        newColumnTableColumn.setText("ID");
        //加入事件监听器
        newColumnTableColumn.addSelectionListener(new SelectionAdapter(){
            boolean asc = true;
            public void widgetSelected(SelectionEvent e){
                tableViewer.setSorter(asc?Sorter.ID_ASC:Sorter.ID_DESC);
                asc = !asc;
            }
        });

        final TableColumn newColumnTableColumn_1 = new TableColumn(table, SWT.NONE);
        newColumnTableColumn_1.setWidth(85);
        newColumnTableColumn_1.setText("姓名");
//        加入事件监听器
        newColumnTableColumn_1.addSelectionListener(new SelectionAdapter(){
            boolean asc = true;
            public void widgetSelected(SelectionEvent e){
                tableViewer.setSorter(asc?Sorter.NAME_ASC:Sorter.NAME_DESC);
                asc = !asc;
            }
        });
        
        final TableColumn newColumnTableColumn_2 = new TableColumn(table, SWT.NONE);
        newColumnTableColumn_2.setWidth(41);
        newColumnTableColumn_2.setText("性别");
//        加入事件监听器
        newColumnTableColumn_2.addSelectionListener(new SelectionAdapter(){
            boolean asc = true;
            public void widgetSelected(SelectionEvent e){
                tableViewer.setSorter(asc?Sorter.SEX_ASC:Sorter.SEX_DESC);
                asc = !asc;
            }
        });
        
        final TableColumn newColumnTableColumn_3 = new TableColumn(table, SWT.NONE);
        newColumnTableColumn_3.setWidth(43);
        newColumnTableColumn_3.setText("年龄");
//        加入事件监听器
        newColumnTableColumn_3.addSelectionListener(new SelectionAdapter(){
            boolean asc = true;
            public void widgetSelected(SelectionEvent e){
                tableViewer.setSorter(asc?Sorter.AGE_ASC:Sorter.AGE_DESC);
                asc = !asc;
            }
        });
        
        final TableColumn newColumnTableColumn_4 = new TableColumn(table, SWT.NONE);
        newColumnTableColumn_4.setWidth(126);
        newColumnTableColumn_4.setText("创建日期");
//        加入事件监听器
        newColumnTableColumn_4.addSelectionListener(new SelectionAdapter(){
            boolean asc = true;
            public void widgetSelected(SelectionEvent e){
                tableViewer.setSorter(asc?Sorter.CREATE_DATE_ASC:Sorter.CREATE_DATE_DESC);
                asc = !asc;
            }
        });
        
        tableViewer.setContentProvider(new ContentProvider());
        tableViewer.setLabelProvider(new TableLabelProvider());
        tableViewer.setInput(People.getPeople());
        
        shell.open();
        shell.setLayout(new FillLayout());
        shell.layout();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }
    }
}

试一下结果是不是出来了？
好了，最后解释几点：
1，sorter中利用了jdk的compareTo来实现比较，当然你也可以根据自己的需求来实现。
2,  sorter中利用了"-"符号来得到正负数字，用来表现升序、降序。
source下载： http://www.blogjava.net/Files/dreamstone/jface-2.rar