小编JLi*_*ink的帖子

我必须为练习创建一个简单的计算.应该有4个按钮和一个文本字段作为显示.这是我的4个按钮的代码:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

class JFrameExample {

  JButton btn1 = new JButton("1");
  JButton btn2 = new JButton("2");
  JButton btn3 = new JButton("+");
  JButton btn4 = new JButton("=");

  public void calculator(){
    JFrame frame = new JFrame("SIMPLE JAVA CALCULATOR");
    frame.setSize(320,320);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setResizable(false);
    frame.setVisible(true);

    JPanel HeadPanel = new JPanel();
    JPanel NumberPanel = new JPanel();
    JPanel LabelPanel = new JPanel();

    NumberPanel.add(btn1);  
    NumberPanel.add(btn2);
    NumberPanel.add(btn3);
    NumberPanel.add(btn4);

    NumberPanel.setLayout(new GridLayout(2,2));
    frame.add(NumberPanel,BorderLayout.CENTER);
  }

  public static void main(String[] args) {
    JFrameExample jf = new JFrameExample();
    jf.calculator();
  } …