本文介绍了如何对SWT列进行降序排序的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
如何进行升序和降序排序.在下面的SWT代码中，升序成功运行，但是当我单击表头时，降序不起作用怎么办?
How to do sorting ascending as well as descending. In the following SWT code ascending is working successfully, but descending not working when I click on the table header how to do?
这是我的以下代码.
package test;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableColumn;
import org.eclipse.swt.widgets.TableItem;
public class SortTable {
private TableRow rows[] = new TableRow[] {
new TableRow(1, "aaa", new Date(1363784269000L), 0.000565529),
new TableRow(2, "abc", new Date(1367784269000L),1.09E-06),
new TableRow(3, "efc", new Date(1363584269000L),0.000273487),
new TableRow(4, "ccc", new Date(1363734269000L),0.000170431),
new TableRow(5, "ddd", new Date(1363734269000L),1.09E-06),
new TableRow(6, "fff", new Date(1363734269000L),0.000273487),
new TableRow(7, "ggg", new Date(1363734269000L),0.000170431),
};
private Table table;
private TableColumn intColumn;
private TableColumn strColumn;
private TableColumn dateColumn;
private TableColumn scientificColumn;
public SortTable() {
Display display = new Display();
Shell shell = new Shell(display);
shell.setLayout(new FillLayout());
table = new Table(shell, SWT.BORDER);
table.setHeaderVisible(true);
intColumn = new TableColumn(table, SWT.NONE);
intColumn.setText("int");
intColumn.setWidth(50);
strColumn = new TableColumn(table, SWT.NONE);
strColumn.setText("string");
strColumn.setWidth(50);
dateColumn = new TableColumn(table, SWT.NONE);
dateColumn.setText("date");
dateColumn.setWidth(100);
scientificColumn = new TableColumn(table, SWT.NONE);
scientificColumn.setText("scientificvalue");
scientificColumn.setWidth(100);
updateTable();
Listener sortListener = new Listener() {
public void handleEvent(Event e) {
TableColumn column = (TableColumn) e.widget;
if (column == intColumn) Arrays.sort(rows, BY_VAL);
if (column == strColumn) Arrays.sort(rows, BY_STR);
if (column == dateColumn) Arrays.sort(rows, BY_DATE);
if (column == scientificColumn) Arrays.sort(rows,BY_VAL );
table.setSortColumn(column);
updateTable();
}
};
Listener reverseSortListener = new Listener() {
public void handleEvent(Event e) {
TableColumn column = (TableColumn) e.widget;
if (column == intColumn) Arrays.sort(rows, Collections.reverseOrder());
if (column == strColumn) Arrays.sort(rows, Collections.reverseOrder());
if (column == dateColumn) Arrays.sort(rows, Collections.reverseOrder());
if (column == scientificColumn) Arrays.sort(rows,Collections.reverseOrder() );
table.setSortColumn(column);
updateTable();
}
};
// intColumn.addListener(SWT.Selection, sortListener);
// strColumn.addListener(SWT.Selection, sortListener);
// dateColumn.addListener(SWT.Selection, sortListener);
// scientificColumn.addListener(SWT.Selection, sortListener);
intColumn.addListener(SWT.Selection, reverseSortListener);
strColumn.addListener(SWT.Selection, reverseSortListener);
dateColumn.addListener(SWT.Selection, reverseSortListener);
scientificColumn.addListener(SWT.Selection, reverseSortListener);
shell.setSize(shell.computeSize(SWT.DEFAULT, SWT.DEFAULT).x, 300);
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
display.dispose();
}
private void updateTable() {
table.removeAll();
for (TableRow row : rows) {
TableItem item = new TableItem(table, SWT.NONE);
// item.setText(row.asString());
item.setText(row.asDouble());
}
}
public final Comparator<TableRow> BY_VAL = new Comparator<TableRow>() {
@Override
public int compare(TableRow o1, TableRow o2) {
if (o1.val < o2.val) return -1;
if (o1.val > o2.val) return 1;
return 0;
}
};
public final Comparator<TableRow> BY_STR = new Comparator<TableRow>() {
@Override
public int compare(TableRow o1, TableRow o2) {
return o1.str.compareTo(o2.str);
}
};
public final Comparator<TableRow> BY_DATE = new Comparator<TableRow>() {
@Override
public int compare(TableRow o1, TableRow o2) {
return o1.date.compareTo(o2.date);
}
};
private class TableRow {
private int val;
private String str;
private Date date;
private double sciVal;
private SimpleDateFormat format = new SimpleDateFormat();
// private NumberFormat formatter = new DecimalFormat("###.#####");
public TableRow(int val, String str, Date date, double sciVal) {
this.val = val;
this.str = str;
this.date = date;
this.sciVal = sciVal;
}
public String[] asString() {
return new String[] {Integer.toString(val), str, format.format(date)};
}
public String[] asDouble() {
return new String[] {Integer.toString(val), str, format.format(date),String.format("%.3E", sciVal)};
}
}
public static void main(String[] args) {
new SortTable();
}
}
推荐答案
Collections.reverseOrder()返回一个比较器，该比较器根据数组内容的自然顺序以相反的顺序对数组进行排序.这不是您此处需要的，因为您想对列进行排序.
Collections.reverseOrder() returns a comparator which sorts the array in reverse order based on the natural ordering of the array contents. This is not what you require here since you want to sort on the columns.
代替使用reverseOrder的版本，该版本接受比较器使用.所以Collections.reverseOrder(BY_VAL)，Collections.reverseOrder(BY_STR)，...
Instead use the version of reverseOrder which accepts the comparator to use. So Collections.reverseOrder(BY_VAL), Collections.reverseOrder(BY_STR), ...
这篇关于如何对SWT列进行降序排序的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！