解决方法
试试这个链接:
How to Use Combo Boxes (The Java™ Tutorials > Creating a GUI With JFC/Swing > Using Swing Components)
class ComboBoxRenderer extends JLabel implements ListCellRenderer { public ComboBoxRenderer() { setOpaque(true); setHorizontalAlignment(CENTER); setVerticalAlignment(CENTER); } //. . .
要么
((JLabel)comboBox.getRenderer()).setHorizontalAlignment(SwingConstants.CENTER);