我正在使用金属 L&F。我想制作一个只有 1 个像素边框的JComboBox 。这不是问题,只要 cb 是可编辑的。这对应于图片中名为“Editable”的第一个 cb。
cb.setEditable(true);
((JTextComponent) (cb.getEditor().getEditorComponent())).setBorder(BorderFactory.createMatteBorder(1, 1, 1, 0, COLOR));
但是当我执行cb.setEditable(false)时,框内会出现一个额外的边框(在图片“Dropdown”中更改为红色,您会在名为“Fixed”的图片中看到原始颜色)。虽然我尝试设置边框并且我也尝试使用我自己的 CellRenderer,但边框仍然被绘制。在我看来,不需要的边框不是来自 CellRenderer。当我尝试从 cb 本身操作边框时(参见注释 //),它只会添加/删除额外的外边框。editorComponent 似乎也不对我负责。
cb.setRenderer(new CbCellRenderer());
//cb.setBorder(BorderFactory.createMatteBorder(1, 1, 1, 1, COLOR));
//cb.setBorder(BorderFactory.createEmptyBorder());
class CbCellRenderer implements ListCellRenderer {
protected DefaultListCellRenderer defaultRenderer = new DefaultListCellRenderer();
@Override
public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
JLabel renderer = (JLabel) defaultRenderer.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
renderer.setBorder(BorderFactory.createEmptyBorder());
return renderer;
}
}
我还尝试了一些 UI 变量,如下面的变量,而不影响此边框。
UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
UIManager.put("ComboBox.selectionForeground", Color.green);
UIManager.put("ComboBox.disabledBackground", Color.green);
...
图片: http: //upload.mtmayr.com/dropdown_frame.png (链接断开)
完整的测试代码:
import java.awt.*;
import java.util.Vector;
import javax.swing.*;
import javax.swing.plaf.basic.BasicComboPopup;
public class ComboTest {
private Vector<String> listSomeString = new Vector<String>();
private JComboBox editableComboBox = new JComboBox(listSomeString);
private JComboBox nonEditableComboBox = new JComboBox(listSomeString);
private JFrame frame;
public final static Color COLOR_BORDER = new Color(122, 138, 153);
public ComboTest() {
listSomeString.add("row 1");
listSomeString.add("row 2");
listSomeString.add("row 3");
listSomeString.add("row 4");
editableComboBox.setEditable(true);
editableComboBox.setBackground(Color.white);
Object child = editableComboBox.getAccessibleContext().getAccessibleChild(0);
BasicComboPopup popup = (BasicComboPopup) child;
JList list = popup.getList();
list.setBackground(Color.white);
list.setSelectionBackground(Color.red);
JTextField tf = ((JTextField) editableComboBox.getEditor().getEditorComponent());
tf.setBorder(BorderFactory.createMatteBorder(1, 1, 1, 0, COLOR_BORDER));
nonEditableComboBox.setEditable(false);
nonEditableComboBox.setBorder(BorderFactory.createEmptyBorder());
nonEditableComboBox.setBackground(Color.white);
Object childNonEditable = nonEditableComboBox.getAccessibleContext().getAccessibleChild(0);
BasicComboPopup popupNonEditable = (BasicComboPopup) childNonEditable;
JList listNonEditable = popupNonEditable.getList();
listNonEditable.setBackground(Color.white);
listNonEditable.setSelectionBackground(Color.red);
frame = new JFrame();
frame.setLayout(new GridLayout(0, 1, 10, 10));
frame.add(editableComboBox);
frame.add(nonEditableComboBox);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocation(100, 100);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
ComboTest ct = new ComboTest();
}
});
}
}