自定义TableRowSorter -新排序顺序

Question

这个自定义TableRowSorter的目的是为我提供不同的列排序顺序。将排序顺序更改为

SortOrder.UNSORTED => SortOrder.ASCENDING => SortOrder.DESCENDING => SortOrder.ASCENDING => SortOrder.DESCENDING => .

至

SortOrder.UNSORTED => SortOrder.ASCENDING => SortOrder.DESCENDING =>SortOrder.UNSORTED => SortOrder.ASCENDING => SortOrder.DESCENDING => .

程序中有变量来自动继续排序顺序，即使列中有一个初始的排序键，它即将排序，就像下面的示例实现一样。

我想知道你是否认为这个程序能做它想要做的事情。我特别感兴趣的是你对该计划的效率的想法，以及是否可以对其进行任何改进。

ADU_SortOrder.java

package order;

import java.util.ArrayList;
import java.util.List;

import javax.swing.SortOrder;
import javax.swing.table.TableModel;
import javax.swing.table.TableRowSorter;

public class ADU_SortOrder<M extends TableModel> extends TableRowSorter<M> {
    public ADU_SortOrder(M model) {
        setModel(model);
    }

    boolean firstTime = true; //Needed in case there are any initial sort keys
    int columnHolder = -1;

    @Override
    public void toggleSortOrder(int column) {
        List<? extends SortKey> sortKeys = getSortKeys();
        if(sortKeys.size() == 0) { //For if there are no initial sort keys
            List<SortKey> keys = new ArrayList<SortKey>();
            keys.add(new SortKey(column, SortOrder.ASCENDING));
            setSortKeys(keys);
            return;
        }

        if (sortKeys.size() > 0 && columnHolder == column || firstTime) {
            if(firstTime) {
                firstTime = false;
                columnHolder = column;
                if(column != sortKeys.get(0).getColumn()) {
                    List<SortKey> keys = new ArrayList<SortKey>(getSortKeys());
                    keys.set(0, new SortKey(column, SortOrder.ASCENDING));
                    setSortKeys(keys);
                    return;
                }
            }

            List<SortKey> keys = new ArrayList<SortKey>(getSortKeys());
            keys.set(0, new SortKey(column, setNextOrder(sortKeys.get(0).getSortOrder())));
            setSortKeys(keys);
            return;
        } else if(sortKeys.size() > 0 && columnHolder != column && !firstTime) {
            List<SortKey> keys = new ArrayList<SortKey>(getSortKeys());
            keys.set(0, new SortKey(column, SortOrder.ASCENDING));
            setSortKeys(keys);
            columnHolder = column;
            return;
        }
        super.toggleSortOrder(column);
    }

    private SortOrder setNextOrder(SortOrder order) {
        switch (order) {
            case ASCENDING:
                return SortOrder.DESCENDING;
            case DESCENDING:
                return SortOrder.UNSORTED;
            case UNSORTED:
                return SortOrder.ASCENDING;
            default:
                return SortOrder.UNSORTED;
        }
    }
}

JTableTest.java

示例实现

import java.awt.GridLayout;

import java.util.List;
import java.util.ArrayList;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.TableModel;
import javax.swing.RowSorter;
import javax.swing.SortOrder;

import order.ADU_SortOrder;

@SuppressWarnings("serial")
public class JTableTest extends JFrame {
    private JTableTest() {
        super("JTable Test");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new GridLayout(1, 1));
        createPanel();
        pack();
        setVisible(true);
    }

    JPanel panel = new JPanel(new GridLayout(1, 1));
    JScrollPane scroll;

    private void createPanel() {
        Object[] headers = {"Select", "Title", "Artist", "Length", "Title"};
        Object[][] sampleData = {{true, "Bat Outta Hell", "Meat Loaf", "673", "Bat Outta Hell"},
                {false, "Spanish Train", "Chris De Burgh", "358", "Spanish Train"},
                {true, "Bat Outta Hell", "Meat Loaf", "673", "Bat Outta Hell"}};
        JTable table = new JTable(sampleData, headers);

        //Sort Order Part
        ADU_SortOrder<TableModel> sortOrder = new ADU_SortOrder<TableModel>(table.getModel());
        List<RowSorter.SortKey> sortKeys = new ArrayList<>();
        sortKeys.add(new RowSorter.SortKey(0, SortOrder.ASCENDING));
        sortOrder.setSortKeys(sortKeys);
        table.setRowSorter(sortOrder);

        scroll = new JScrollPane(table);
        panel.add(scroll);
        getContentPane().add(panel);
    }

    public static void main(String[] args) {
        new JTableTest();
    }
}

欢迎并赞赏任何其他意见、建议或建议。

Answer 1

if(sortKeys.size() == 0) { //For if there are no initial sort keys

写起来更规范

        if (sortKeys.isEmpty()) {

而且，要么size为0，要么大于0。没有其他选择。因此，您不需要检查size是否大于0。如果没有从这个块中提取return，则size必须大于0。所以你不需要检查。

if (sortKeys.size() > 0 && columnHolder == column || firstTime) {

和

} else if(sortKeys.size() > 0 && columnHolder != column && !firstTime) {

如果我们放弃size检查，这些可能只是

        if (columnHolder == column || firstTime) {

和

        } else {

这

super.toggleSortOrder(column);

是不必要的。在达到这个目标之前，您总是return。