单击后防止JButton repaint（）

Question

我有一个按钮。我要在单击后更改背景。我的问题是按钮自动调用paintCompenent（）。如何预防呢？我希望单击按钮后，该按钮将为蓝色，但仍为红色

package test;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class ButtonDemo extends JButton implements ActionListener{

    public ButtonDemo() {
        this.setText("FUCK YOU");
        this.addActionListener(this);
    }
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        setBackground(Color.RED);
    }
    public static void main(String[] args){
        JFrame frame = new JFrame();
        JPanel contentPane = new JPanel();
        frame.setContentPane(contentPane);
        contentPane.add(new ButtonDemo());
        frame.setSize(500, 500);

        frame.setVisible(true);

    }
    @Override
    public void actionPerformed(ActionEvent e) {
        this.setBackground(Color.BLUE);
    }  
}

Answer 1

您在paintComponent替代中将背景设置为红色。

您完全不需要覆盖paintComponent即可获得想要的效果。

这里是更新的代码。我添加了几行。

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class ButtonDemo extends JButton 
        implements ActionListener {

    private static final long serialVersionUID = 1L;

    public ButtonDemo() {
        this.setText("F*CK YOU");
        this.setBackground(Color.RED);
        this.addActionListener(this);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame("Button Demo");
                frame.setDefaultCloseOperation(
                        JFrame.EXIT_ON_CLOSE);
                JPanel contentPane = new JPanel();
                contentPane.setLayout(new BorderLayout());
                frame.setContentPane(contentPane);
                contentPane.add(new ButtonDemo());
                frame.setSize(500, 500);
                frame.setVisible(true);
            }
        });
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        this.setBackground(Color.BLUE);
    }
}