JButton仅在鼠标悬停时起作用

Question

I am a beginner in Java and programming overall, and I started by making a simple JFrame with a few buttons. Now when I created the buttons, the only way they would appear is if I hovered over them with my mouse.

import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.GridBagLayout;

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

public class Main extends JFrame {

public Main() {
    setTitle("Test");
    setSize(600, 500);
    setResizable(false);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setLocationRelativeTo(null);
    setLayout(new FlowLayout());
    JPanel p = new JPanel();
    JButton b = new JButton("Derp");
    p.add(b);
    add(b);
    setVisible(true);
    revalidate();
    repaint();
} 

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

public void paint(Graphics g) {
    g.drawString("Under Construction...", 240, 250);

}

}

Help would be appreciated, also please note I do not know that much about Java and I don't know a descent amount of the languages. Also, a way to make the buttons have the Aero texture instead of the default one would be nice :)

Answer 1

Since you override paint you need to call super.paint(g); as the first line.

public void paint(Graphics g) {
    super.paint(g); // <-- add this.
    g.drawString("Under Construction...", 240, 250);
}

Also, you should move your logic off the main() thread; like

SwingUtilities.invokeLater(new Runnable() {
    public void run() {
        new Main();
    }
});