开始编辑 JTable Cell 时选择所有数据

Question

我正在尝试制作一个像 Excel 一样工作的表格。这意味着，当用户开始将数据插入单元格时，单元格中的内容将被选择并由插入的新数据更改。

Answer 1

您可以为表格创建自定义 TableCellEditor。该类将有一个 TextField 的实例变量，我们将其称为 textField。那么 getTableCellEditorComponent 方法可能如下所示：

public Component getTableCellEditorComponent(JTable table, Object value, 
                             boolean isSelected, int row, int column ) {
    textField.setText(value.toString());
    textField.selectAll();
    return textField;
}

Answer 2

如果表中只有字符串数据并且只需要一个编辑器，那么创建自定义编辑器效果很好。但是，如果您有多种不同类型的数据，例如字符串、整数、双精度、货币、百分比等，它们都使用 JTextField 作为编辑器，那么您需要创建多个自定义编辑器。

您可以阅读表格全选编辑器 另一种可能的解决方案。

Answer 3

请注意，还有另一种可能性，您可以覆盖 JTable#prepareEditor，如下所示：

@Override
public Component prepareEditor(TableCellEditor editor, int row, int column) {
    Component c = super.prepareEditor(editor, row, column);
    if (c instanceof JTextComponent) {
        ((JTextComponent) c).selectAll();
    } 
    return c;
}

Answer 4

当通过单击鼠标开始编辑时，上述解决方案不起作用。

对于某些人来说，解决方案是在 invokeLater() 中调用 selectAll() ，以便在分派鼠标事件后选择文本，但这对我不起作用（可能是因为我正在使用 Substance 外观和感觉？ )

Swing 内部稍后获取 mouseReleased() 事件并再次更改插入符号，如以下堆栈跟踪所示：

at javax.swing.text.JTextComponent.fireCaretUpdate(Unknown Source)
at javax.swing.text.JTextComponent$MutableCaretEvent.fire(Unknown Source)
at javax.swing.text.JTextComponent$MutableCaretEvent.mouseReleased(Unknown Source)
at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)
at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)
at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)
at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)
at java.awt.AWTEventMulticaster.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at javax.swing.plaf.basic.BasicTableUI$Handler.repostEvent(Unknown Source)

这是我的解决方案：
监听插入符号位置的变化，并且在单元格编辑开始后第一次选择从所有选定变为未选定时，再次调用 selectAll()。插入符侦听器可以通过自定义单元格编辑器安装，如下所示，或者在自定义 JTable 中重写的 editCellAt() 方法中安装。

private class SelectAllCellEditor extends DefaultCellEditor
{
    public SelectAllCellEditor( JTextField tf )
    {
        super( tf );
    }

    /**
     * Flag to ensure we only install the caret listener on the editor once.
     */
    boolean listenerInstalled   = false;
    /**
     * Primes the caret listener to override deselection when the first mouseReleased() event is reposted to the editor.
     */
    boolean overrideDeselection = false;

    @Override
    public Component getTableCellEditorComponent( JTable table , Object value , boolean isSelected , int row , int column )
    {
        final JFormattedTextField tf = ( JFormattedTextField ) super.getTableCellEditorComponent( table , value , isSelected , row , column );

        if( !listenerInstalled )
        {
            tf.addCaretListener( new CaretListener( )
            {
                int lastDot     = 0;
                int lastMark    = 0;

                @Override
                public void caretUpdate( CaretEvent e )
                {
                    if( overrideDeselection )
                    {
                        int length = tf.getText( ) == null ? 0 : tf.getText( ).length( );

                        boolean wasAllSelected = ( lastDot == 0 && lastMark == length ) || ( lastDot == length && lastMark == 0 );
                        boolean nowNoneSelected = ( e.getDot( ) == 0 && e.getMark( ) == 0 ) || ( e.getDot( ) == length && e.getMark( ) == length );

                        if( wasAllSelected )
                        {
                            // don't try to override again until the next time cell editing is started
                            overrideDeselection = false;

                            // only re-select all if the selection went to none; otherwise the user clicked the cell and dragged to select part of the text
                            if( nowNoneSelected )
                            {
                                tf.selectAll( );
                            }
                        }
                    }

                    lastDot = e.getDot( );
                    lastMark = e.getMark( );
                }
            } );
            listenerInstalled = true;
        }

        // Prime the caret listener to override deselection when the first mouseReleased() event is reposted to the editor.
        overrideDeselection = true;
        tf.selectAll( );
        return tf;
    }
}

Answer 5

如果您的目标是在编辑开始时清空单元格，则无需使用 selectAll()。只需将值设置为null。

实现示例：

（覆盖 DefaultCellEditor 中的 getTableCellEditorComponent()）

TableCellEditor myCellEditor = new DefaultCellEditor(new JTextField()){
    @Override
    public Component getTableCellEditorComponent(JTable table, Object value,
                boolean isSelected, int row, int column)
    {
        // empty the cell on edit start
        delegate.setValue( (editorComponent instanceof JTextField)? null : value);
        return editorComponent;
    }
};

Answer 6

你应该看看 extJS。不过，有一个相当陡峭的学习曲线..