JTable，自定义标题渲染器和排序图标 [英] JTable, custom header renderer and sorting icons

问题描述

在JTable标头上设置自定义渲染器时，我得到了预期的视觉行为（边框，字体，对齐，...），但我无法设法获取排序后通常出现的LaF排序图标。

这是设置自定义标题渲染器的代码：

 枚举< TableColumn的> columns = getColumnModel（）。getColumns（）; 
 while（columns.hasMoreElements（））
 columns.nextElement（）。setHeaderRenderer（new XDeliveryTableHeaderRenderer（））; 
  

这是自定义标题渲染器的摘录：

  public class MyTableHeaderRenderer extends JLabel implements TableCellRenderer {
 private static final Font labelFont = new Font（Arial，Font.BOLD，11）; 
 
 @Override 
 public Component getTableCellRendererComponent（JTable table，Object value，boolean isSelected，boolean hasFocus，int row，int column）{$ b $ setFont（labelFont）; 
 setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 setText（value.toString（））; 
 setBorder（BorderFactory.createEtchedBorder（））; 
返回此; 
 
 
 $ / code $ / pre 
 
 $ p 
 
 
 
 
 
 $尝试委托L& F安装的渲染器： 
 
 
  
 > public class MyTableHeaderRenderer implements TableCellRenderer {
 private static final Font labelFont = new Font（Arial，Font.BOLD，11）; 
 
私人TableCellRenderer委托; 
 
 public MyTableHeaderRenderer（TableCellRenderer delegate）{
 this.delegate = delegate; 
 
 $ b @Override 
公共组件getTableCellRendererComponent（JTable表，Object值，boolean isSelected，布尔hasFocus，int行，int列）{
 
 Component c = delegate.getTableCellRendererComponent（table，value，isSelected，hasFocus，row，column）; 
 
 if（c instance of JLabel）{
 JLabel label =（JLabel）c; 
 label.setFont（labelFont）; 
 label.setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 label.setBorder（BorderFactory.createEtchedBorder（））; 
} 
 return c; 
} 
} 
 
 //用法：
 JTableHeader header = table.getTableHeader（）; 
 header.setDefaultRenderer（new MyTableHeaderRenderer（header.getDefaultRenderer（）））; 
  
正如kleopatra所警告的，这可能不是最稳定的解决方案，请参阅这个错误报告我刚刚投入生产。该问题的记者建议使用更新TableColumn＃getDefaultRenderer中委托渲染器的自定义Table / TableColumn子类。
 
While setting a custom renderer on a JTable header I  get the expected visual behavior (borders, font, alignment, ...) but I can't manage to get the LaF sorting icons that usually appear when the rows are sorted. 

This is the code for setting the custom header renderer:
Enumeration<TableColumn> columns = getColumnModel().getColumns();
   while (columns.hasMoreElements())
   columns.nextElement().setHeaderRenderer(new XDeliveryTableHeaderRenderer());
This is an excerpt of the custom header renderer:
public class MyTableHeaderRenderer extends JLabel implements TableCellRenderer {
     private static final Font labelFont = new Font("Arial", Font.BOLD, 11);

     @Override
     public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
        setFont(labelFont);
        setHorizontalAlignment(SwingConstants.CENTER);
        setText(value.toString());
        setBorder(BorderFactory.createEtchedBorder());
        return this;
     }
}
Any hints?
解决方案
Try delegating to the L&F installed renderer:
public class MyTableHeaderRenderer implements TableCellRenderer {
 private static final Font labelFont = new Font("Arial", Font.BOLD, 11);

 private TableCellRenderer delegate;

 public MyTableHeaderRenderer(TableCellRenderer delegate) {
     this.delegate = delegate;
 } 

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

    Component c = delegate.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);

    if(c instanceof JLabel) {
        JLabel label = (JLabel) c;
        label.setFont(labelFont);
        label.setHorizontalAlignment(SwingConstants.CENTER);
        label.setBorder(BorderFactory.createEtchedBorder());
    }
    return c;
 }
}

// Usage:
JTableHeader header = table.getTableHeader();
header.setDefaultRenderer(new MyTableHeaderRenderer(header.getDefaultRenderer()));
As kleopatra warned, this might not be the most stable solution, see this bug report which I just got in production. The reporter of that issue suggest using a custom Table/TableColumn sub classes which updating the delegate renderer in TableColumn#getDefaultRenderer.

                        
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