与色的项目和焦点的色的jcombobox

我正在尝试制作带有彩色物品的彩色下拉列表（请参阅下面的代码）。 combobox失去焦点后，颜色会被应用。

这是正确的行为吗？

当combobox具有焦点时，如何才能使前景和/或背景颜色发生变化？

谢谢

import java.awt.*; import java.awt.event.*; import java.util.*; import javax.swing.*; import javax.swing.border.*; public class DropDown { enum Colors { red(Color.red), orange(Color.orange), green(Color.green), yellow(Color.yellow), blue(Color.blue); Colors(Color color) { this.color = color; } static String[] listModel() { java.util.List values = Arrays.asList(values()); String s = values.toString().replaceAll(" ", ""); return s.substring(1, s.length() - 1).split(","); } final Color color; } static class ColoredCellRenderer implements ListCellRenderer { protected DefaultListCellRenderer defaultRenderer = new DefaultListCellRenderer(); private final static Dimension preferredSize = new Dimension(0, 20); public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) { JLabel renderer = (JLabel) defaultRenderer.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus); if (index != -1) if (value instanceof String) renderer.setForeground(Colors.valueOf((String) value).color); else System.out.println("not a string"); else System.out.println("in getListCellRendererComponent, index=-1"); renderer.setPreferredSize(preferredSize); return renderer; } } private static JComboBox addLabeledComboBox(Container c, String label, String[] model) { JPanel panel = new JPanel(); panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS)); Border border = BorderFactory.createLineBorder(Color.green, 1); panel.setBorder(border); JLabel l = new JLabel(label); panel.add(l); final JComboBox comboBox = new JComboBox(model); comboBox.setName(label); l.setLabelFor(comboBox); comboBox.setRenderer(new ColoredCellRenderer()); panel.add(comboBox); c.add(panel); return comboBox; } private static void addContent(Container c) { c.setLayout(new BoxLayout(c, BoxLayout.Y_AXIS)); ActionListener actionListener = new ActionListener() { @Override public void actionPerformed(ActionEvent e) { if (e.getSource() instanceof JComboBox) { final JComboBox comboBox = (JComboBox) e.getSource(); Object selected = comboBox.getSelectedItem(); String string = (String) selected; Color color = Colors.valueOf(string).color; int i = comboBox.getSelectedIndex(); if (i != -1) { System.out.println("comboBox " + comboBox.getName() + " " + color); comboBox.setForeground(color); System.out.println(comboBox.hasFocus()); // comboBox.repaint(); } else System.out.println("in actionListener selected=" + selected); } else System.out.println("in actionListener selected is not a comboBox"); } }; c.add(new JButton("button")); for (int i = 0; i < 2; i++) { JPanel panel = new JPanel(); Border border = BorderFactory.createLineBorder(Color.red, 1); panel.setBorder(border); panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS)); panel.add(new JLabel("label " +(i+1))); JComboBox comboBox = addLabeledComboBox(panel, "" + (i + 1), Colors.listModel()); comboBox.addActionListener(actionListener); comboBox.setSelectedIndex(0); // select something c.add(panel); } } private static void createAndShowGUI() { JFrame frame = new JFrame("Colored JComboBox"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); addContent(frame.getContentPane()); frame.pack(); frame.setVisible(true); } public static void main(String[] args) { javax.swing.SwingUtilities.invokeLater(new Runnable() { @SuppressWarnings("synthetic-access") public void run() { createAndShowGUI(); } }); } } 

Answer 1

这是另一种方法：

 //JList#setSelectionForeground(...) version static class ColoredCellRenderer implements ListCellRenderer { protected DefaultListCellRenderer defaultRenderer = new DefaultListCellRenderer(); private final Color selectionBackground = new Color(240,200,200); public Component getListCellRendererComponent( JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) { Color fgc = Colors.valueOf((String)value).color; if(index<0) { //comboBox.setForeground(fgc); //Windows, CDE/Motif Look & Feel list.setSelectionForeground(fgc); list.setSelectionBackground(selectionBackground); } JLabel renderer = (JLabel) defaultRenderer.getListCellRendererComponent( list, value, index, isSelected, cellHasFocus); if (index != -1) { renderer.setForeground(fgc); } return renderer; } } //html version static class ComboHtmlRenderer extends DefaultListCellRenderer { private final Color selectionBackground = new Color(240,200,200); @Override public Component getListCellRendererComponent( JList list, Object value, int index, boolean isSelected, boolean hasFocus) { Color fgc = Colors.valueOf((String)value).color; if(index<0) { list.setSelectionBackground(selectionBackground); } JLabel l = (JLabel)super.getListCellRendererComponent( list, value, index, isSelected, hasFocus); l.setText(""+value); l.setBackground(isSelected?selectionBackground:list.getBackground()); return l; } private static String hex(Color c) { return String.format("#%06x", c.getRGB()&0xffffff); } } 

Answer 2

请拆分Editor和Renderer，并将这两种方法添加到DefaultListCellRenderer中

• cellHasFocus

• isSelected

例

 import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.border.LineBorder; import javax.swing.event.EventListenerList; class ColorComboBoxEditor1 implements ComboBoxEditor { final protected JLabel editor; //final protected JButton editor; private EventListenerList listenerList = new EventListenerList(); ColorComboBoxEditor1(Color initialColor) { editor = new JLabel(""); /*editor = new JButton(""); editor.setBackground(initialColor); ActionListener actionListener = new ActionListener() { @Override public void actionPerformed(ActionEvent e) { Color currentBackground = editor.getBackground(); Color color = JColorChooser.showDialog(editor, "Color Chooser", currentBackground); if ((color != null) && (currentBackground != color)) { //editor.setBackground(color); editor.setForeground(color); fireActionEvent(color); } } }; editor.addActionListener(actionListener);*/ } @Override public void addActionListener(ActionListener l) { listenerList.add(ActionListener.class, l); } @Override public Component getEditorComponent() { return editor; } @Override public Object getItem() { return editor.getBackground(); } @Override public void removeActionListener(ActionListener l) { listenerList.remove(ActionListener.class, l); } @Override public void selectAll() { } @Override public void setItem(Object newValue) { if (newValue instanceof Color) { Color color = (Color) newValue; //editor.setBackground(color); editor.setForeground(color); editor.setText(String.valueOf(newValue)); } else { try { Color color = Color.decode(newValue.toString()); //editor.setBackground(color); editor.setForeground(color); editor.setText(String.valueOf(newValue)); } catch (NumberFormatException e) { } } } protected void fireActionEvent(Color color) { Object listeners[] = listenerList.getListenerList(); for (int i = listeners.length - 2; i >= 0; i -= 2) { if (listeners[i] == ActionListener.class) { ActionEvent actionEvent = new ActionEvent(editor, ActionEvent.ACTION_PERFORMED, color.toString()); ((ActionListener) listeners[i + 1]).actionPerformed(actionEvent); } } } } class ColorCellRenderer1 implements ListCellRenderer { private DefaultListCellRenderer defaultRenderer = new DefaultListCellRenderer(); // Width doesn't matter as the combo box will size private final static Dimension preferredSize = new Dimension(0, 20); @Override public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) { JLabel renderer = (JLabel) defaultRenderer.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus); if (value instanceof Color) { //renderer.setBackground((Color) value); renderer.setBackground(Color.white); renderer.setForeground((Color) value); } if (cellHasFocus || isSelected) { renderer.setBorder(new LineBorder(Color.DARK_GRAY)); } else { renderer.setBorder(null); } renderer.setPreferredSize(preferredSize); return renderer; } } class ColorComboBoxEditorRendererDemo1 { public ColorComboBoxEditorRendererDemo1() { Color colors[] = {Color.BLACK, Color.BLUE, Color.GREEN, Color.RED, Color.WHITE, Color.YELLOW}; JFrame frame = new JFrame("Color JComboBox"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); final JComboBox comboBox = new JComboBox(colors); comboBox.setEditable(true); comboBox.setRenderer(new ColorCellRenderer1()); Color color = (Color) comboBox.getSelectedItem(); ComboBoxEditor editor = new ColorComboBoxEditor1(color); comboBox.setEditor(editor); frame.add(comboBox, BorderLayout.NORTH); final JLabel label = new JLabel(); label.setOpaque(true); label.setBackground((Color) comboBox.getSelectedItem()); frame.add(label, BorderLayout.CENTER); ActionListener actionListener = new ActionListener() { @Override public void actionPerformed(ActionEvent actionEvent) { Color selectedColor = (Color) comboBox.getSelectedItem(); label.setBackground(selectedColor); } }; comboBox.addActionListener(actionListener); frame.setSize(300, 200); frame.setVisible(true); } public static void main(String args[]) { SwingUtilities.invokeLater(new Runnable() { @Override public void run() { ColorComboBoxEditorRendererDemo1 cCBERD1 = new ColorComboBoxEditorRendererDemo1(); } }); } } 

Answer 3

示例中的前景文本颜色似乎正常工作。 某些其他颜色由组件的UI委托管理，用于给定的外观和感觉，如下所示。 请注意，委托可以选择以保持各种状态对比度的方式应用颜色，例如选中，启用等。您可以在文章UIManager Defaults中了解更多信息。

 public static void main(String[] args) { UIManager.put("ComboBox.background", new ColorUIResource(Color.lightGray)); UIManager.put("ComboBox.selectionBackground", new ColorUIResource(Color.magenta)); UIManager.put("ComboBox.selectionForeground", new ColorUIResource(Color.yellow)); javax.swing.SwingUtilities.invokeLater(new Runnable() { @SuppressWarnings("synthetic-access") public void run() { createAndShowGUI(); } }); }