swing Java：如何将框架的背景色设置为组合框中相应的选定颜色名称

Question

请注意，我正在尝试将框架的背景色设置为组合框中选定的颜色名称。虽然我使用了repaint（）方法，但它仍然不起作用

是不是JFrame类不能着色？或者，还有别的方法吗？以下是我所尝试的：

有人能帮我写一些片段吗

Answer 1

我建议创建自己的JPanel并将其设置为内容窗格。（注意声明容器的位置和构造函数的第二行）。这通常被认为是“更清洁”

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;

import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class GUI1410 extends JFrame implements ActionListener
{

    private JComboBox comboBox;
    private JCheckBox background, foreground;
    private JButton okButton, cancelButton;
    private String[] colors = { "RED", "GREEN", "BLUE" };
    private Color color[] = { Color.RED, Color.GREEN, Color.BLUE };

    private JPanel checkBoxPanel, buttonPanel;
    Container container = new JPanel();

    public GUI1410()
    {

        super("ColorSelect");
        setContentPane(container);
        this.getContentPane().setBackground(color[0]);

        comboBox = new JComboBox(colors);
        comboBox.setMaximumRowCount(2);
        comboBox.addItemListener(new ItemListener() {

            @Override
            public void itemStateChanged(ItemEvent event)
            {

                if (event.getStateChange() == ItemEvent.SELECTED)
                {
                    container.setBackground(color[comboBox.getSelectedIndex()]);
                    container.repaint();
                }

            }

        });

        background = new JCheckBox("Background");
        foreground = new JCheckBox("Foreground");

        okButton = new JButton("Ok");
        okButton.addActionListener(this);
        cancelButton = new JButton("Cancel");
        cancelButton.addActionListener(this);

        checkBoxPanel = new JPanel();
        checkBoxPanel.add(background);
        checkBoxPanel.add(foreground);

        buttonPanel = new JPanel();
        buttonPanel.add(okButton);
        buttonPanel.add(cancelButton);

        container.add(comboBox, BorderLayout.NORTH);
        container.add(checkBoxPanel, BorderLayout.CENTER);
        container.add(buttonPanel, BorderLayout.SOUTH);

        setVisible(true);
        setBounds(400, 200, 300, 120);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    }

    @Override
    public void actionPerformed(ActionEvent event)
    {

        if (event.getSource() == okButton)
        {
            container.setBackground(color[comboBox.getSelectedIndex()]);
        }
        else if (event.getSource() == cancelButton)
        {
            System.exit(0);
        }

    }

    public static void main(String[] args)
    {
        new GUI1410();
    }

}