Java简易计算器(带详细注释)

package JSJ; import javax.swing.*; import java.awt.*; import java.awt.event.*; public class Jsq extends JFrame implements ActionListener{ double num1,num2,num3; boolean end,add,mul,sub,div; JTextField t =new JTextField(); JButton b1 = new JButton("1"); JButton b2 = new JButton("2"); JButton b3 = new JButton("3"); JButton b4 = new JButton("+"); JButton b5 = new JButton("4"); JButton b6 = new JButton("5"); JButton b7 = new JButton("6"); JButton b8 = new JButton("-"); JButton b9 = new JButton("7"); JButton b10 = new JButton("8"); JButton b11 = new JButton("9"); JButton b12 = new JButton("*"); JButton b13 = new JButton("."); JButton b14 = new JButton("0"); JButton b15 = new JButton("="); JButton b16 = new JButton("/"); JPanel p1=new JPanel(); JPanel p2=new JPanel(); public Jsq(){ //窗体属性 setTitle("计算器"); setResizable(false); setBounds(100,100,230,230); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //文本框属性 t.setEditable(false); t.setHorizontalAlignment(JTextField.CENTER); t.setColumns(18); p1.add(t); add(p1,"North"); //按钮属性 GridLayout l=new GridLayout(4,0); l.setVgap(10); l.setHgap(10); p2.setLayout(l); add(p2,"Center"); p2.add(b1); p2.add(b2); p2.add(b3); p2.add(b4); p2.add(b5); p2.add(b6); p2.add(b7); p2.add(b8); p2.add(b9); p2.add(b10); p2.add(b11); p2.add(b12); p2.add(b13); p2.add(b14); p2.add(b15); p2.add(b16); //窗体左右两侧添加空白标签 JLabel ll=new JLabel(); ll.setPreferredSize(new Dimension(10,0)); add(ll,"Wset"); JLabel rl=new JLabel(); rl.setPreferredSize(new Dimension(10,0)); add(rl,"East"); b1.addActionListener(this); b2.addActionListener(this); b3.addActionListener(this); b4.addActionListener(this); b5.addActionListener(this); b6.addActionListener(this); b7.addActionListener(this); b8.addActionListener(this); b9.addActionListener(this); b10.addActionListener(this); b11.addActionListener(this); b12.addActionListener(this); b13.addActionListener(this); b14.addActionListener(this); b15.addActionListener(this); b16.addActionListener(this); setVisible(true); } public static void main(String args[]){ Jsq f= new Jsq(); } public void num(int i){ String s=String.valueOf(i); if(end){//判断操作数输入数否结束 t.setText("0"); end=false; } if((t.getText()).equals("0")){ //如果文本框的内容为0，则覆盖文本框的内容 t.setText(s); } else{ //如果文本框的内容不为0，则在内容后面添加数字 str = t.getText()+ s; t.getText(str); } } public void sign(int i){ if(i==1){ add=true;mul=false;sub=false;div=false; } if(i==2){ add=false;mul=false;sub=true;div=false; } if(i==3){ add=false;mul=true;sub=false;div=false; } if(i==4){ add=false;mul=false;sub=false;div=true; } num1=Double.parseDouble(t.getText()); end=true; } public void point(){ String s; if(t.getText().indexOf('.')<0){ s=t.getText()+"."; t.setText(s); } } public void eql(){ num2=Double.parseDouble(t.getText()); if(add) num3=num1+num2; if(mul) num3=num1*num2; if(sub) num3=num1-num2; if(div) num3=num1/num2; String s=String.valueOf(num3); t.setText(s); end=true; } public void actionPerformed(ActionEvent e){ if(e.getSource()==b1) num(1); if(e.getSource()==b2) num(2); if(e.getSource()==b3) num(3); if(e.getSource()==b5) num(4); if(e.getSource()==b6) num(5); if(e.getSource()==b7) num(6); if(e.getSource()==b9) num(7); if(e.getSource()==b10) num(8); if(e.getSource()==b11) num(9); if(e.getSource()==b14) num(0); if(e.getSource()==b4) sign(1); if(e.getSource()==b8) num(2); if(e.getSource()==b12) num(3); if(e.getSource()==b16) num(4); if(e.getSource()==b14) point(); if(e.getSource()==b15) eql(); } }