Question

我正在编写JFrame表单中的可编辑组合框，但我想更改背景颜色。

该计划如何运作：如果我点击“按”按钮，那么组合框的背景需要变成黑色。

我试过了：

1

cbo.setBackground(Color.BLACK);

但它没有做任何事情

2

cbo.getEditor().getEditorComponent().setBackground(Color.BLACK);

((JTextField) cbo.getEditor().getEditorComponent()).setOpaque(true);

这是：

代码示例：

public class NewJFrame extends javax.swing.JFrame {

    private JComboBox cboCategorie;

    public NewJFrame() {
        initComponents();

        cboCategorie = new JComboBox();
        cboCategorie.setBounds(10, 10, 250, 26);
        cboCategorie.setVisible(true);
        cboCategorie.setEditable(true);
        this.add(cboCategorie);

    }

private void pressActionPerformed(java.awt.event.ActionEvent evt) {
        cboCategorie.getEditor().getEditorComponent().setBackground(Color.BLACK);
        ((JTextField) cboCategorie.getEditor().getEditorComponent()).setOpaque(true);
}

我正在使用Java JDK7

任何sugestions？

Answer 1

请参阅我的代码示例

enter image description here

import java.awt.*;
import java.util.Vector;
import javax.swing.*;
import javax.swing.UIManager;
import javax.swing.plaf.ColorUIResource;
import javax.swing.plaf.metal.MetalComboBoxButton;

public class MyComboBox {

    private Vector<String> listSomeString = new Vector<String>();
    private JComboBox someComboBox = new JComboBox(listSomeString);
    private JComboBox editableComboBox = new JComboBox(listSomeString);
    private JComboBox non_EditableComboBox = new JComboBox(listSomeString);
    private JFrame frame;

    public MyComboBox() {
        listSomeString.add("-");
        listSomeString.add("Snowboarding");
        listSomeString.add("Rowing");
        listSomeString.add("Knitting");
        listSomeString.add("Speed reading");
//
        someComboBox.setPrototypeDisplayValue("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
        someComboBox.setFont(new Font("Serif", Font.BOLD, 16));
        someComboBox.setEditable(true);
        someComboBox.getEditor().getEditorComponent().setBackground(Color.YELLOW);
        ((JTextField) someComboBox.getEditor().getEditorComponent()).setBackground(Color.YELLOW);
//
        editableComboBox.setPrototypeDisplayValue("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
        editableComboBox.setFont(new Font("Serif", Font.BOLD, 16));
        editableComboBox.setEditable(true);
        JTextField text = ((JTextField) editableComboBox.getEditor().getEditorComponent());
        text.setBackground(Color.YELLOW);
        JComboBox coloredArrowsCombo = editableComboBox;
        Component[] comp = coloredArrowsCombo.getComponents();
        for (int i = 0; i < comp.length; i++) {// hack valid only for Metal L&F
            if (comp[i] instanceof MetalComboBoxButton) {
                MetalComboBoxButton coloredArrowsButton = (MetalComboBoxButton) comp[i];
                coloredArrowsButton.setBackground(null);
                break;
            }
        }
//
        non_EditableComboBox.setPrototypeDisplayValue("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx");
        non_EditableComboBox.setFont(new Font("Serif", Font.BOLD, 16));
//
        frame = new JFrame();
        frame.setLayout(new GridLayout(0, 1, 10, 10));
        frame.add(someComboBox);
        frame.add(editableComboBox);
        frame.add(non_EditableComboBox);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocation(100, 100);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        UIManager.put("ComboBox.background", new ColorUIResource(Color.yellow));
        UIManager.put("JTextField.background", new ColorUIResource(Color.yellow));
        UIManager.put("ComboBox.selectionBackground", new ColorUIResource(Color.magenta));
        UIManager.put("ComboBox.selectionForeground", new ColorUIResource(Color.blue));
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                MyComboBox aCTF = new MyComboBox();
            }
        });
    }
}

Answer 2

结果很容易。创建渲染器并设置背景颜色。然后覆盖渲染器的 setOpaque 方法以始终将不透明度设置为 true。

class PDFChooser extends JComboBox<String>  {
    PDFChooser() {
        setRenderer(new Renderer());
    }
    class Renderer extends DefaultListCellRenderer {
        @Override 
        public void setOpaque(boolean makeBackGroundVisible) {
            super.setOpaque(true);     // THIS DOES THE TRICK
        }
        @Override
        public Component getListCellRendererComponent(JList<?> list, 
                    Object value, int index, 
                    boolean isSelected, boolean cellHasFocus) {
            setText((String)value);
            setBackground(Color.cyan);
            return this;
        }
    }
}

如果想让弹出菜单使用LAF背景，可以添加一个PopupMenuListener来注意弹出的时候。那时，setOpaque 方法会将不透明度设置为 false。

Answer 3

我可以在JComboBox中更改所选项目的颜色。

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    JComboBox cmb = new JComboBox();
    cmb.setEditable(true);
    cmb.setEditor(new WComboBoxEditor(getContentPane().getBackground()));

    // To change the arrow button's background        
    cmb.setUI(new BasicComboBoxUI(){
        protected JButton createArrowButton()
        {
            BasicArrowButton arrowButton = new BasicArrowButton(BasicArrowButton.SOUTH, null, null, Color.GRAY, null);
            return arrowButton;
        }
    });
    cmb.setModel(new DefaultComboBoxModel(new String[] { "a", "b", "c" }));

如果您想更改JCombobox中除选定项目之外的项目颜色，请自定义ListCellRenderer。

更改背景颜色可编辑JComboBox

3 个答案: