我想要一个没有箭头按钮（完成）的 JComboBox，它在启用时具有绿色背景，在禁用时具有灰色背景（未完成）。我还为下拉列表使用了自定义渲染器（完成）
我检查了 BasicComboBoxUI 的源代码并尝试覆盖一些方法，但没有任何反应。下拉菜单始终具有灰色/蓝色背景。
这是我最后一次尝试的SSCCE。我尝试了我能想到的一切。请给我一个提示，我迷路了。
import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.Rectangle;
import javax.swing.BorderFactory;
import javax.swing.DefaultComboBoxModel;
import javax.swing.DefaultListCellRenderer;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
import javax.swing.plaf.basic.BasicComboBoxUI;
public class DropDownBackground
{
public static void main(final String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
final JComboBox dropdown = new JComboBox(new DefaultComboBoxModel(new String[] { "one", "two", "three" }));
dropdown.setRenderer(new ComboBoxListCellRenderer());
dropdown.setUI(new BasicComboBoxUI()
{
@Override
public void paint(final Graphics g, final JComponent c)
{
final Rectangle r = this.rectangleForCurrentValue();
this.paintCurrentValueBackground(g, r, true);
this.paintCurrentValue(g, r, true);
}
@Override
public void paintCurrentValueBackground(final Graphics g, final Rectangle bounds, final boolean hasFocus)
{
final Color t = g.getColor();
if (this.comboBox.isEnabled())
g.setColor(Color.GREEN);
else
g.setColor(Color.GRAY);
g.fillRect(bounds.x, bounds.y, bounds.width, bounds.height);
g.setColor(t);
}
@Override
protected JButton createArrowButton()
{
return new JButton()
{
@Override
public int getWidth()
{
return 0;
}
};
}
});
dropdown.setBackground(Color.GREEN);
final JPanel p = new JPanel();
p.add(dropdown);
final JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(new JScrollPane(p));
f.setSize(800, 200);
f.setLocation(0, 0);
f.setVisible(true);
}
});
}
public static class ComboBoxListCellRenderer extends DefaultListCellRenderer
{
/**
*
*/
private static final long serialVersionUID = 1L;
@Override
public Component getListCellRendererComponent(final JList list, final Object value, final int index, final boolean isSelected, final boolean cellHasFocus)
{
this.setToolTipText((String) value);
if (isSelected)
{
this.setBackground(Color.RED);
this.setForeground(Color.WHITE);
}
else
{
this.setBackground(Color.WHITE);
this.setForeground(Color.BLACK);
}
this.setText((String) value);
this.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
return this;
}
}
}