JAVA显示不了面板

[HeyXu66]

package shiyan3; import javax.swing.*; import java.awt.*; import java.awt.event.*; public class Shiyan3{ public static void main(String[] args) { cal calculator =new cal(); calculator.setVisible(true); } } class cal extends JFrame { // 实例化面板 JPanel panel1 = new JPanel(); JPanel panel2 = new JPanel(); JPanel panel3 = new JPanel(); //文本区 JTextField answer=new JTextField(20); //按钮定义 JButton[] b = new JButton[10]; //十个数字 JButton clear=new JButton("清除"); JButton equal=new JButton("="); JButton point=new JButton("."); JButton plus=new JButton("+"); JButton minus=new JButton("-"); JButton multi=new JButton("×"); JButton division=new JButton("÷"); public cal() { //基本属性 setSize(400,600); setDefaultCloseOperation(EXIT_ON_CLOSE); setLocation(300,400); this.setResizable(false); setLayout(new FlowLayout()); // 设置布局管理器 panel1.setLayout(new GridLayout(2,1)); panel2.setLayout(new GridLayout(4,3)); panel3.setLayout(new GridLayout(4,1)); for (int i =9; i>=0; i--) { b[i] = new JButton(Integer.toString(i));// 实例化数字按钮 //b[i].addActionListener(new MyListener1()); panel2.add(b[i]); // 增加按钮到面板 } panel1.add(answer); panel1.add(clear); panel2.add(point); panel2.add(equal); panel3.add(plus); panel3.add(minus); panel3.add(multi); panel3.add(division); add(panel1); add(panel2); add(panel3); setVisible(true); } }

[TheLissandra]

你在cal类中new 一个Frame出来，然后把panel们加在Frame上，把Frame.setVisible(true);显示为可见 再加一句 Frame名.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 试一下能不能看见