poner - que es jcombobox en java

Jcombobox de colores con elementos de colores y enfoque

Question

Estoy tratando de hacer una lista desplegable de colores con elementos de colores (consulte el código a continuación). El color se aplica después de que el cuadro combinado pierda el foco.

¿Es este comportamiento correcto?

¿Cómo puedo hacer que el primer plano y / o el color de fondo cambien cuando el cuadro combinado tiene el foco?

Gracias

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<Colors> 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

Aquí hay otro enfoque:

//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("<html><font color="+hex(fgc)+">"+value);
    l.setBackground(isSelected?selectionBackground:list.getBackground());
    return l;
  }
  private static String hex(Color c) {
    return String.format("#%06x", c.getRGB()&0xffffff);
  }
}

Answer 2

Divide Editor y Renderer, y agrega a DefaultListCellRenderer estos dos métodos

• cellHasFocus

• isSelected

ejemplo

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

Los colores de texto de primer plano en su ejemplo parecen funcionar correctamente. Ciertos otros colores son gestionados por el delegado de UI del componente para un Look & Feel determinado, como se muestra a continuación. Tenga en cuenta que el delegado puede optar por aplicar un color de una manera que preserve el contraste en varios estados, por ejemplo, seleccionado, habilitado, etc. Puede obtener más información en el artículo UIManager Predeterminados .

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();
        }
    });
}