java - 如何从 Java/SWT 表中删除新数据将替换旧数据的所有行？

Question

我正在尝试从 SWT 表中删除所有当前行，然后用新数据替换这些行。

我已经创建了示例代码来显示我遇到问题的地方。在示例中，双击监听器将调用其中一个方法，尝试从表中删除当前数据。通过 repopulate() 方法替换它。

SWT 表应用程序来源:

package javaTools;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
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 QuickTableExampleA {

    public static void main(String[] args) {
        String data = "ljames@ubunzeus: ~|0x0480002c\n"
                + "Stack Overflow - Where Developers Learn, Share, & Build"
                + " Careers - Google Chrome|0x0520000a\n"
                + "Inbox - L. D. James - Mozilla Thunderbird|0x05208736\n";

        Display display = new Display();
        Shell shell = new Shell(display);

        shell.setSize(700, 500);
        shell.setText("My Table Smipplet");
        shell.setLayout(new FillLayout());


        Table table = new Table(shell, SWT.BORDER);

        TableColumn column1 = new TableColumn(table, SWT.LEFT);
        TableColumn column2 = new TableColumn(table, SWT.LEFT);

        column1.setText("Window");
        column2.setText("Window ID");
        column1.setWidth(600);
        column2.setWidth(70);

        table.setHeaderVisible(true);
        String[] array = data.split("\n");
        for (int i = 0; i < array.length; i++) {
            // System.out.println(array[i]);
            String[] array2 = array[i].split("\\|");
            TableItem newrow = new TableItem(table, SWT.NONE);
            newrow.setText(new String[] { array2[0], array2[1] });
        }

        table.addListener(SWT.MouseDoubleClick, new Listener()
        {
            @Override
            public void handleEvent(Event event)
            {
                Point pt = new Point(event.x, event.y);
                TableItem item = table.getItem(pt);
                if (item != null)
                {
                    /* Iterate over all columns and check if event is contained */
                    for (int col = 0; col < table.getColumnCount(); col++)
                    {
                        Rectangle rect = item.getBounds(col);
                        if (rect.contains(pt))
                        {
                            System.out.println("The WindowID is" + item.getText(1));

                            /*  
                            The following methods are my efforts to remove the
                            current data so that only the new repopulated data
                            will be in the table.
                            */

                            // table.removeAll();
                            // table.clearAll();
                            // removerowbyrow();

                            repopulateTable();
                        }
                    }
                }
            }

            private void removerowbyrow() {
                int rowcount = table.getItemCount();
                System.out.println("Number of rows: " + rowcount);
                System.out.println("Removing all rows 1 by 1");
                for(int i = 0; i <table.getItemCount(); i++) {
                    rowcount = table.getItemCount();
                    System.out.println("Removing the first row of: " + rowcount);
                    table.remove(0);
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }

            private void repopulateTable() {
                System.out.println("This is a repopulateTable.");
                String[] array = getdata();
                for (int i = 0; i < array.length; i++) {
                    // System.out.println(array[i]);
                    String[] array2 = array[i].split("\\|");
                    TableItem newrow = new TableItem(table, SWT.NONE);
                    newrow.setText(new String[] { array2[0], array2[1] });
                }
            }
        });

        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
              display.sleep();
          }
          display.dispose();
    }
    public static String[] getdata() {
        String data = "swt table delete records - Google Search - Google Chrome|0x0480002c\n"
                + "javaTools/src/javaTools/QuickTableExampleA.java -"
                + " /home/users/l/j/ljames/workspace - Eclipse|0x05a000aa\n"
                + "swt java how to delete a range of rows - Google Search - Google Chrome|0x05208736\n";

        String[] array = data.split("\n");
        return array;
    }
}

我有三个被注释掉的函数。这是因为程序在每种方法上都会崩溃。我希望有人能够找出这三个函数的问题所在。他们是:

• table.removeAll();
• table.clearAll();
• 删除rowbyrow();

取消注释后，三个函数的错误输出为:

table.removeAll();

The WindowID is0x0520000a
This is a repopulateTable.
Exception in thread "main" org.eclipse.swt.SWTException: Widget is disposed
    at org.eclipse.swt.SWT.error(Unknown Source)
    at org.eclipse.swt.SWT.error(Unknown Source)
    at org.eclipse.swt.SWT.error(Unknown Source)
    at org.eclipse.swt.widgets.Widget.error(Unknown Source)
    at org.eclipse.swt.widgets.Widget.checkWidget(Unknown Source)
    at org.eclipse.swt.widgets.TableItem.getBounds(Unknown Source)
    at javaTools.QuickTableExampleA$1.handleEvent(QuickTableExampleA.java:62)
    at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
    at org.eclipse.swt.widgets.Display.sendEvent(Unknown Source)
    at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
    at org.eclipse.swt.widgets.Display.runDeferredEvents(Unknown Source)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Unknown Source)
    at javaTools.QuickTableExampleA.main(QuickTableExampleA.java:111)

table.clearAll();

这个没有给出错误。它留下空白行。重新填充显示在先前日期所在位置的下方。它不会替换表格，而是附加到表格中。

repopulateTable();

The WindowID is0x0520000a
Number of rows: 3
Removing all rows 1 by 1
Removing the first row of: 3
Removing the first row of: 2
This is a repopulateTable.
Exception in thread "main" org.eclipse.swt.SWTException: Widget is disposed
    at org.eclipse.swt.SWT.error(Unknown Source)
    at org.eclipse.swt.SWT.error(Unknown Source)
    at org.eclipse.swt.SWT.error(Unknown Source)
    at org.eclipse.swt.widgets.Widget.error(Unknown Source)
    at org.eclipse.swt.widgets.Widget.checkWidget(Unknown Source)
    at org.eclipse.swt.widgets.TableItem.getBounds(Unknown Source)
    at javaTools.QuickTableExampleA$1.handleEvent(QuickTableExampleA.java:62)
    at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
    at org.eclipse.swt.widgets.Display.sendEvent(Unknown Source)
    at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
    at org.eclipse.swt.widgets.Display.runDeferredEvents(Unknown Source)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Unknown Source)
    at javaTools.QuickTableExampleA.main(QuickTableExampleA.java:115)

Answer 1

“小部件已处置”错误是因为您在已处置(丢弃)的表格项上调用 TableItem.getBounds。

一旦调用Table.removeAll或Table.remove，您必须立即终止正在查看旧表项的循环。此时您无法对旧项目进行任何进一步操作。

Table.clearAll 不会丢弃旧的表格项目，它只是将它们设置为空白，因此这正在执行它应该做的事情。

因此，总之，使用 Table.removeAll 但立即停止循环 - 看起来您只需要 break:

  for (int col = 0; col < table.getColumnCount(); col++)
   {
     Rectangle rect = item.getBounds(col);
     if (rect.contains(pt))
      {
        System.out.println("The WindowID is" + item.getText(1));

        table.removeAll();

        repopulateTable();

        // Stop loop now, further reference to 'item' is invalid
        break;
      }
   }