java - 失去对 JTable 单元格的选择

Question

当您单击 JTable 单元格时，该行将变为“选定”，我希望这样当我单击其他任何内容时，它就会变为未选定状态。

我正在考虑在 table 上使用鼠标监听器来执行此操作，但不确定如何识别(不在 table 上单击)。有什么想法吗？

这就是我正在尝试的:

 jTable.addMouseListener(new MouseAdapter(){
                @Override
                public void mouseClicked(MouseEvent e){
                    System.out.println("click");}});

但是，当我单击第一列时，它只会打印单击，而当我单击非表格的内容时，它肯定不会打印单击。

当我识别出该事件时，我会调用此方法:

public void loseCellFocus()
{
    jTable.getCellEditor().stopCellEditing();
    jTable.clearSelection();
}

Answer 1

使用附加到 JTable 的 FocusListener，这会告诉您焦点何时离开表格。

参见How to Write a Focus Listener了解更多详情

例如...

    table.addFocusListener(new FocusAdapter() {
        @Override
        public void focusLost(FocusEvent e) {
            loseCellFocus();
        }           
    });

当然，只有当键盘焦点转移到能够接收键盘焦点的新组件时，这才有效

This causes my loseCellFocus() method to be called right away, as soon as I click on any cell it's called

您可以使用JTable#setSurrendersFocusOnKeystroke或者检查焦点已转移到的组件是否是 JTable

的子组件

例如...

table.addFocusListener(new FocusAdapter() {
    @Override
    public void focusLost(FocusEvent e) {
        if (e.getOppositeComponent().getParent() != table) {
            loseCellFocus();
        }
    }
});

可运行示例...

好吧，事情变得困惑了。我不仅必须向 JTable 添加一个 FocusListener，而且还必须确保将一个 FocusListener 添加到 TableCellEditor 组件中:P

这只是一个概念证明，我有专门的类，能够通过一些通用接口(interface)引发事件或触发所需的功能

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.EventQueue;
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;
import javax.swing.DefaultCellEditor;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.JViewport;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.EmptyBorder;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellEditor;

public class Test {

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

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {
            setLayout(new BorderLayout());

            JTable table = new JTable(new DefaultTableModel(10, 10));

            JTextField editorField = new JTextField(10);
            editorField.setBorder(new EmptyBorder(1, 1, 1, 1));
            editorField.addFocusListener(new FocusAdapter() {
                @Override
                public void focusLost(FocusEvent e) {
                    TableCellEditor cellEditor = table.getCellEditor();
                    if (cellEditor != null) {
                        if (!cellEditor.stopCellEditing()) {
                            cellEditor.cancelCellEditing();
                        }
                    }

                    Component gotFocus = e.getOppositeComponent();
                    if (!gotFocus.equals(table)) {
                        table.clearSelection();
                    }
                }
            });
            DefaultCellEditor editor = new DefaultCellEditor(editorField);
            table.setDefaultEditor(Object.class, editor);

            add(new JScrollPane(table));
            table.addFocusListener(new FocusAdapter() {

                @Override
                public void focusLost(FocusEvent e) {
                    Component gotFocus = e.getOppositeComponent();
                    if (!gotFocus.getParent().equals(table)) {
                        TableCellEditor cellEditor = table.getCellEditor();
                        if (cellEditor != null) {
                            if (!cellEditor.stopCellEditing()) {
                                cellEditor.cancelCellEditing();
                            }
                        }
                        table.clearSelection();
                    }
                }

            });

            JTextField field = new JTextField(10);
            add(field, BorderLayout.SOUTH);
        }

    }

}

AWTEventListener 示例...

好吧，我真的不想走这条路，因为它最终会陷入困惑的交叉条件，但是。基本上，这会监视所有 MouseEvent 和 FocusEvent，它会执行一些向后的 sumsults 来测试有效条件(因为我们需要确保不仅如果 JTable 是事件的一部分，但如果编辑器是事件的一部分)并根据这些结果，停止单元格编辑并清除选择...

import java.awt.AWTEvent;
import java.awt.Component;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.KeyboardFocusManager;
import java.awt.Toolkit;
import java.awt.event.AWTEventListener;
import java.awt.event.FocusEvent;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.EmptyBorder;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellEditor;

public class Test {

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

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        public TestPane() {
            JTable table = new JTable(new DefaultTableModel(5, 5));
            setLayout(new GridBagLayout());
            setBorder(new EmptyBorder(20, 20, 20, 20));
            GridBagConstraints gbc = new GridBagConstraints();
            gbc.gridwidth = GridBagConstraints.REMAINDER;
            add(new JScrollPane(table), gbc);
            add(new JTextField(10), gbc);

            Toolkit.getDefaultToolkit().addAWTEventListener(new AWTEventListener() {
                @Override
                public void eventDispatched(AWTEvent event) {
                    if (event instanceof FocusEvent) {
                        FocusEvent focusEvent = (FocusEvent) event;
                        if (focusEvent.getID() == FocusEvent.FOCUS_LOST) {
                            Component focusTo = focusEvent.getOppositeComponent();
                            Component focusFrom = focusEvent.getComponent();

                            JTable table = getTableFrom(focusFrom);
                            if (focusTo == null || !focusTo.getParent().equals(table)) {

                                stopCellEditing(table);
                                clearSelection(table);

                            }
                        }
                    } else if (event instanceof MouseEvent) {
                        MouseEvent mouseEvent = (MouseEvent) event;
                        if (mouseEvent.getID() == MouseEvent.MOUSE_CLICKED) {
                            Component focusOwner = KeyboardFocusManager.getCurrentKeyboardFocusManager().getFocusOwner();
                            JTable table = getTableFrom(focusOwner);
                            System.out.println("     table = " + table);
                            System.out.println("focusOwner = " + focusOwner);
//                          if ((table != null && mouseEvent.getComponent() != table) || (focusOwner != null && !focusOwner.getParent().equals(table))) {
                            if ((table != null && mouseEvent.getComponent() != table) && (focusOwner != null && !focusOwner.getParent().equals(table))) {
                                stopCellEditing(table);
                                clearSelection(table);
                            }
                        }
                    }
                }

                protected JTable getTableFrom(Component component) {
                    JTable table = null;
                    if (component instanceof JTable) {
                        table = (JTable) component;
                    } else if (component != null && component.getParent() instanceof JTable) {
                        table = (JTable) component.getParent();
                    }
                    return table;
                }

                protected void clearSelection(JTable table) {
                    if (table != null) {
                        table.clearSelection();
                    }
                }

                protected void stopCellEditing(JTable table) {

                    if (table != null) {
                        TableCellEditor cellEditor = table.getCellEditor();
                        if (cellEditor != null) {
                            if (!cellEditor.stopCellEditing()) {
                                cellEditor.cancelCellEditing();
                            }
                        }
                    }
                }
            }, AWTEvent.FOCUS_EVENT_MASK | AWTEvent.MOUSE_EVENT_MASK);
        }

    }

}

此示例基本上适用于所有 JTable(注册 AWTEventListener 后)，但您可以通过更改某些事件将其配置为监视单个表来源并将它们相互比较:P