向JTable单元格添加JComboBox。所选项目不停留

Question

我在这里看了几篇文章，但找不到答案。

我已经成功地将JComboBox添加到Jtable单元格中。但是，所选项目没有被“记住”。

更具体地说：

澄清一下，信息并没有丢失。虽然组合框没有直观地显示选择了什么设备，但选择是保存的。然而，我希望用户能够直观地看到他们刚刚选择的内容，而不必再次选择行。

这使我相信我使用的自定义呈现器一定有错误

public class PreDefJobPlanDialogDataTable extends CygnusAbstractTableModel{

 private static final long serialVersionUID = 1344977933386754731L;

 static final ColumnData columns[] = {
    new ColumnData( "Sel." , 25, 10000, JLabel.LEFT),
    new ColumnData( "Type", 25, 10000, JLabel.LEFT),
    new ColumnData( "Status", 25,  10000,JLabel.LEFT ),
    new ColumnData( "Title", 100,  10000,JLabel.LEFT ),
    new ColumnData( "Equipment Class", 50, 10000, JLabel.LEFT),
    new ColumnData( "Equipment", 100, 10000, JLabel.LEFT)
};

...

public boolean isCellEditable(int rowIndex, int columnIndex) {
    boolean ret = false;
    if( columnIndex == 0 || columnIndex == 5 ) {
        ret = true;             
    }
    return ret;
}

...

public Object getValueAt(int rowIndex, int columnIndex) {
    Object ret = " ";

    if( rowIndex >= 0 && rowIndex < getRowCount() ) {
        PreDefJobPlan obj = (PreDefJobPlan)modelData.get( rowIndex );
        switch( columnIndex ) {

            case 0: ret = obj.getGroupFlag();
            break;
            case 1: ret = obj.getType();
            break;
            case 2: ret = obj.getStatus();
            break;
            case 3: ret = obj.getTitle();
            break;
            case 4: ret = obj.getLevel1Area();
            break;
            case 5: ret = obj.getLevel2Area();
            break;
            case 9: ret = obj.getPreDefJobPlanID();
            break;
            default: ret = " ";
        }
    }
    return ret;
}

...

public void setValueAt( Object obj, int row, int col ) {
    // get the object
    PreDefJobPlan o = (PreDefJobPlan) this.modelData.get( row );
    switch( col ) {
        case 0:
            o.setGroupFlag((Boolean) obj);
        break;
        case 5:
            o.setLevel2Area((Equipment) obj);
        break;
        default: ;
    }
}

protected void createTable() {
    PreDefJobPlanDialogDataTable dataModel = new PreDefJobPlanDialogDataTable();
    dataModel.setTimeOffset( 0 );

    this.view.getOrdersTable().setHighlighters(HighlighterFactory.createAlternateStriping());
    this.view.getOrdersTable().setAutoCreateColumnsFromModel( false );
    this.view.getOrdersTable().setModel( dataModel );
    this.view.getOrdersTable().setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    this.view.getOrdersTable().setTransferHandler(new TableRowTransferHandler(this.view.getOrdersTable())); 

  for( int i = 0; i < dataModel.getColumnCount(); i++ ) {   
            if( i== 0 ) {
                ...
            }
            else if (i == 5){

                TableCellRenderer renderer = new ComboCellRenderer(); 
                ca.cygnusconsulting.utilities.ColumnData col = dataModel.getColumn( i );
                JComboBox tableCheckBox = new JComboBox();
                tableCheckBox.setModel( lvl1Model );
                tableCheckBox.setAlignmentX(JComboBox.LEFT_ALIGNMENT);
                tableCheckBox.setBackground(this.view.getOrdersTable().getBackground());
                TableCellEditor editor = new ComboBoxCellEditor(tableCheckBox);
                TableColumnExt column = new TableColumnExt( i, col.getWidth(), renderer, editor );
                column.setMaxWidth(col.getMaxWidth());
                this.view.getOrdersTable().addColumn( column ); 
            }
            else{
                ...
            }
        } 

呈现器：

public class ComboCellRenderer extends JComboBox implements TableCellRenderer {

protected static Border noFocusBorder = new EmptyBorder(1,1,1,1);
protected static Border focusBorder = UIManager.getBorder("Table.focusCellHighlightBorder");

 public ComboCellRenderer() {
  super();
  setOpaque(true);

 }

  public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected,
  boolean hasFocus, int row, int column) {

    setBackground(isSelected && !hasFocus ? table.getSelectionBackground() : table.getBackground());
    setForeground(isSelected && !hasFocus ? table.getSelectionForeground() : table.getForeground());
    setFont(table.getFont());
    setSelectedItem(value);

  return this;
  }


}

Answer 1

通常，您应该使用默认的单元格呈现器来显示您的单元格内容，并且只在编辑时显示组合框。

要理解JTable单元格呈现器的一个关键概念是，单个单元格呈现器通常用于绘制包含相同类型数据的所有单元格。

如果您特别希望组合框用于呈现单元格，则单元格为空的原因是自定义呈现器组合框中没有添加项。您应该使用与单元格编辑器组合框相同的值填充单元格呈现器组合框。