Wiele kolorów dla każdej pozycji w JComboBox

Question

Próbuję utworzyć ComboBox, który używa różnych kolorów dla różnych elementów. Napisałem kod testowy, ale nie działa. Dodanie renderera powoduje awarię programu, ale skomentowanie go powoduje, że pole wyświetla się w ramce.

Czy jest coś czego mi brakuje lub czy robię to w niewłaściwy sposób? Próbowałem użyć samouczka custom ComboBox Renderer jako przykładu.

Oto mój kod:

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; 


    } 

} 

Dzięki!

Answer 1

Czy to masz na myśli?

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; 
    } 
}