Più colori per ciascun elemento in JComboBox

Question

Sto provando a creare un ComboBox che utilizza colori diversi per articoli diversi. Ho scritto un codice di prova ma non sembra funzionare. L'aggiunta nel renderer fa in modo che il programma si arresti in modo anomalo ma commentandolo rende la visualizzazione della scatola attiva nella cornice.

C'è qualcosa che mi manca o lo sto facendo nel modo sbagliato? Ho provato a utilizzare il tutorial custom ComboBox Renderer come esempio.

Ecco il mio codice:

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; 


    } 

} 

Grazie!

Answer 1

È questo che intendi?

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; 
    } 
}