JComboBox中每个项目的多种颜色

我正在尝试制作一个ComboBox，它为不同的项目使用不同的颜色。 我写了一些测试代码，但它似乎不起作用。 添加渲染器会导致程序崩溃，但将其注释掉会使框显示在框架中。

有什么我想念的，或者我做错了吗？ 我尝试使用自定义ComboBox Renderer教程作为示例。

这是我的代码：

TestComboColor.java

import java.awt.Color; import javax.swing.JComboBox; import javax.swing.JFrame; public class TestComboColor { static Color[] colors = {Color.BLUE, Color.GRAY, Color.RED}; static String[] strings = {"Test1", "Test2", "Test3"}; public static void main(String[] args) { JFrame frame = new JFrame("JAVA"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JComboBox cmb = new JComboBox(); ComboBoxRenderer renderer = new ComboBoxRenderer(cmb); renderer.setColors(colors); renderer.setStrings(strings); cmb.setRenderer(renderer); frame.add(cmb); frame.pack(); frame.setVisible(true); } } 

ComboBoxRenderer.java

 import java.awt.Color; import java.awt.Component; import javax.swing.JComboBox; import javax.swing.JLabel; import javax.swing.JList; import javax.swing.JPanel; import javax.swing.ListCellRenderer; public final class ComboBoxRenderer extends JPanel implements ListCellRenderer { private static final long serialVersionUID = -1L; private Color[] colors; private String[] strings; JPanel textPanel; JLabel text; public ComboBoxRenderer(JComboBox combo) { textPanel = new JPanel(); textPanel.add(this); text = new JLabel(); text.setOpaque(true); text.setFont(combo.getFont()); textPanel.add(text); } public void setColors(Color[] col) { colors = col; } public void setStrings(String[] str) { strings = str; } public Color[] getColors() { return colors; } public String[] getStrings() { return strings; } @Override public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) { if (isSelected) { setBackground(list.getSelectionBackground()); } else { } if (colors.length != strings.length) { System.out.println("colors.length does not equal strings.length"); return this; } else if (colors == null) { System.out.println("use setColors first."); return this; } else if (strings == null) { System.out.println("use setStrings first."); return this; } text.setText(strings[index]); text.setForeground(colors[index]); text.setBackground(getBackground()); return text; } } 

谢谢！

Answer 1

你是这个意思吗？

 import java.awt.Color; import java.awt.Component; import javax.swing.*; public class TestComboColor { static Color[] colors = {Color.BLUE, Color.GRAY, Color.RED}; static String[] strings = {"Test1", "Test2", "Test3"}; public static void main(String[] args) { JFrame frame = new JFrame("JAVA"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JComboBox cmb = new JComboBox(strings); ComboBoxRenderer renderer = new ComboBoxRenderer(cmb); renderer.setColors(colors); renderer.setStrings(strings); cmb.setRenderer(renderer); frame.add(cmb); frame.pack(); frame.setVisible(true); } } class ComboBoxRenderer extends JPanel implements ListCellRenderer { private static final long serialVersionUID = -1L; private Color[] colors; private String[] strings; JPanel textPanel; JLabel text; public ComboBoxRenderer(JComboBox combo) { textPanel = new JPanel(); textPanel.add(this); text = new JLabel(); text.setOpaque(true); text.setFont(combo.getFont()); textPanel.add(text); } public void setColors(Color[] col) { colors = col; } public void setStrings(String[] str) { strings = str; } public Color[] getColors() { return colors; } public String[] getStrings() { return strings; } @Override public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) { if (isSelected) { setBackground(list.getSelectionBackground()); } else { setBackground(Color.WHITE); } if (colors.length != strings.length) { System.out.println("colors.length does not equal strings.length"); return this; } else if (colors == null) { System.out.println("use setColors first."); return this; } else if (strings == null) { System.out.println("use setStrings first."); return this; } text.setBackground(getBackground()); text.setText(value.toString()); if (index>-1) { text.setForeground(colors[index]); } return text; } }