我嘗試添加該面板:主類與類添加一個JPanel到一個JFrame
import javax.swing.*;
import java.awt.*;
class TopPanel extends JPanel{
public TopPanel() {
JPanel panel = new JPanel();
JLabel label = new JLabel("Course Lookup GUI");
panel.add(label);
panel.setVisible(true);
}
}
要像這樣的框架:
import javax.swing.*;
import java.awt.*;
class CourseGUI extends JFrame{
public CourseGUI() {
this.setLayout(new FlowLayout());
this.setLocation(200,200);
TopPanel tPan = new TopPanel();
MiddlePanel mPan = new MiddlePanel();
this.add(tPan);
this.add(mPan);
this.setVisible(true);
}
public static void main(String[] args){
CourseGUI cGUI = new CourseGUI();
}
}
但沒有什麼是添加到該幀,我得到一個空的窗口。我究竟做錯了什麼?