列表：设置方法导致问题 - IndexOutOfBoundsException

Question

当我尝试调用 tableUpdate 方法时，我得到一个 IndexOutOfBoundsException。
我认为我使用set() 方法的方式有问题。我曾尝试将a -1 放在这样的int row = members.size() -1 上，但这并没有解决问题。你能帮我么？

class MyTableModel extends AbstractTableModel {
        /**
                 *
                 */
        private static final long serialVersionUID = 1L;
        private List<Member> members = new ArrayList<Member>();

        public MyTableModel(List<Member> members) {
                this.members = members;
        }

        public void addMember(Member m) {
                members.add(m);
                int row = members.size() - 1;
                fireTableRowsInserted(row, row);
        }

        public void removeMemberFromTable(int row) {
                members.remove(row);
                fireTableRowsDeleted(row, row);
        }

        public void tableUpdate(int row, Member m) {
                row = members.size();
                members.set(row, m);
                fireTableRowsUpdated(row, row);
        }

        public List<Member> getMembers() {
                return new ArrayList<Member>(members);
        }

        @Override
        public int getColumnCount() {
                return 8;
        }

        @Override
        public int getRowCount() {
                return members.size();
        }

        @Override
        public Object getValueAt(int rowIndex, int columnIndex) {
                Member m = members.get(rowIndex);

                switch (columnIndex) {
                case 0:
                        return m.getMemberId();

                case 1:
                        return m.getfName();

                case 2:
                        return m.getlName();

                case 3:
                        return m.getAddress();

                case 4:
                        return m.getZipCode();

                case 5:
                        return m.getCity();

                case 6:
                        return m.getEmail();

                case 7:
                        return m.getPhoneNo();

                default:
                        return "";
                }
        }

        public String getColumnName(int column) {
                switch (column) {
                case 0:
                        return "MedlemsID";

                case 1:
                        return "Fornavn";

                case 2:
                        return "Efternavn";

                case 3:
                        return "Adresse";

                case 4:
                        return "Postnummer";

                case 5:
                        return "By";

                case 6:
                        return "Email";

                case 7:
                        return "Telefonnr";
                default:
                        return "";
                }
        }

        public Class<?> getColumnClass(int columnIndex) {
                switch (columnIndex) {
                case 0:
                        return String.class;

                case 1:
                        return String.class;

                case 2:
                        return String.class;

                case 3:
                        return String.class;

                case 4:
                        return String.class;

                case 5:
                        return String.class;

                case 6:
                        return String.class;

                case 7:
                        return String.class;

                default:
                        return String.class;
                }
        }

例外

Exception in thread "AWT-EventQueue-0" java.lang.IndexOutOfBoundsException: Index: 2, Size: 2
        at java.util.ArrayList.rangeCheck(ArrayList.java:604)
        at java.util.ArrayList.set(ArrayList.java:397)
        at gui.MyTableModel.tableUpdate(ShowMembersGUI.java:179)
        at gui.EditMemberGUI$1.actionPerformed(EditMemberGUI.java:108)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
        at java.awt.Component.processMouseEvent(Component.java:6505)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3312)
        at java.awt.Component.processEvent(Component.java:6270)
        at java.awt.Container.processEvent(Container.java:2229)
        at java.awt.Component.dispatchEventImpl(Component.java:4861)
        at java.awt.Container.dispatchEventImpl(Container.java:2287)
        at java.awt.Component.dispatchEvent(Component.java:4687)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
        at java.awt.Container.dispatchEventImpl(Container.java:2273)
        at java.awt.Window.dispatchEventImpl(Window.java:2719)
        at java.awt.Component.dispatchEvent(Component.java:4687)
        at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:735)
        at java.awt.EventQueue.access$200(EventQueue.java:103)
        at java.awt.EventQueue$3.run(EventQueue.java:694)
        at java.awt.EventQueue$3.run(EventQueue.java:692)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
        at java.awt.EventQueue$4.run(EventQueue.java:708)
        at java.awt.EventQueue$4.run(EventQueue.java:706)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:705)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)

Answer 1

列表是零索引的。这意味着最后一个元素的大小为 - 1，而不是大小。你有

   row = members.size();
   members.set(row, m); // tries to "overwrite" instance at index = size, 
                        // which is always greater than the last index.

这将始终抛出 IndexOutOfBoundsException，因为它是零索引，所以从来没有一个 size 的索引。

Answer 2

您想替换最后一个元素之后的元素。这没有意义。也许您想检查索引是否在范围内，如下所示：

public void tableUpdate(int row, Member m) {
    if (row < members.size()) {
        members.set(row, m);
        fireTableRowsUpdated(row, row);
    }
}