Question

用java编辑简易计算器我的思路是：文本1和3监听数字0~9和“。”

Answer 1

import java.awt.BorderLayout;

import java.awt.Button;

import java.awt.Container;

import java.awt.GridLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.KeyEvent;

import java.awt.event.KeyListener;

import java.awt.event.WindowAdapter;

import java.awt.event.WindowEvent;

import javax.swing.JFrame;

import javax.swing.JOptionPane;

import javax.swing.JPanel;

import javax.swing.JTextField;

import javax.swing.WindowConstants;

public class Caculator extends JFrame implements ActionListener,KeyListener{

private JTextField tf=new JTextField();

private float x=0;

private float y=0;

private int code=0;

private boolean enable;

private boolean first;

private String str="";

public Caculator(){

Container ct=this.getContentPane();

this.setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);

tf.setHorizontalAlignment(JTextField.RIGHT);

//tf.setText("0");

enable=true;

first=true;

ct.add(tf,BorderLayout.NORTH);

JPanel panel=new JPanel();

panel.setLayout(new GridLayout(4,4));

this.addWindowListener(new WindowAdapter(){

public void windowClosing(WindowEvent e){

if(JOptionPane.YES_OPTION==JOptionPane.showConfirmDialog(Caculator.this,"确定要关闭程序吗?","提示",JOptionPane.OK_CANCEL_OPTION,JOptionPane.QUESTION_MESSAGE)){

e.getWindow().setVisible(false);

e.getWindow().dispose();

System.exit(0);

}

}

});

Button btn=null;

btn=new Button("1");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("2");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("3");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("+");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("4");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("5");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("6");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("-");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("7");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("8");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("9");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("*");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("0");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button(".");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("/");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

btn=new Button("=");

panel.add(btn);

btn.addActionListener(this);

btn.addKeyListener(this);

this.add(panel,BorderLayout.CENTER);

}

/**

* @param args

*/

public static void main(String[] args) {

// TODO Auto-generated method stub

Caculator mainframe=new Caculator();

mainframe.setTitle("testing Caculator");

mainframe.setSize(400,400);

mainframe.setVisible(true);

}

public void actionPerformed(ActionEvent e) {

// TODO Auto-generated method stub

if(e.getActionCommand()=="+"){

x= Float.parseFloat(tf.getText());

code=0;

this.tf.setText("");

}

if(e.getActionCommand()=="-"){

x= Float.parseFloat(tf.getText());

code=1;

this.tf.setText("");

}

if(e.getActionCommand()=="*"){

x= Float.parseFloat(tf.getText());

code=2;

this.tf.setText("");

}

if(e.getActionCommand()=="/"){

x= Float.parseFloat(tf.getText());

code=3;

this.tf.setText("");

}

if(e.getActionCommand()!="+"&&e.getActionCommand()!="-"&&e.getActionCommand()!="*"&&e.getActionCommand()!="/"&&e.getActionCommand()!="="){

if(enable){

if(first){

System.out.println("haha");

tf.setText(e.getActionCommand());

first=false;

}

else {

tf.setText(tf.getText()+e.getActionCommand());

}

}

else {

tf.setText(e.getActionCommand());

enable=true;

}

}

if(e.getActionCommand()=="="){

switch(code){

case 0:

y=x+Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

case 1:

y=x-Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

case 2:

y=x*Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

case 3:

y=x/Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

}

}

}

public void keyPressed(KeyEvent e) {

// TODO Auto-generated method stub

if(e.getKeyChar()=='+'){

x= Float.parseFloat(tf.getText());

code=0;

this.tf.setText("");

}

if(e.getKeyChar()=='-'){

x= Float.parseFloat(tf.getText());

code=1;

this.tf.setText("");

}

if(e.getKeyChar()=='*'){

x= Float.parseFloat(tf.getText());

code=2;

this.tf.setText("");

}

if(e.getKeyChar()=='/'){

x= Float.parseFloat(tf.getText());

code=3;

this.tf.setText("");

}

if(e.getKeyChar()=='1'||e.getKeyChar()=='2'||e.getKeyChar()=='3'||e.getKeyChar()=='0'

||e.getKeyChar()=='4'||e.getKeyChar()=='5'||e.getKeyChar()=='6'||e.getKeyChar()=='.'

||e.getKeyChar()=='7'||e.getKeyChar()=='8'||e.getKeyChar()=='9'){

System.out.println("hai");

if(enable){

if(first){

System.out.println("hehe");

str=Character.toString(e.getKeyChar());

tf.setText(str);

first=false;

}

else {

str=Character.toString(e.getKeyChar());

tf.setText(tf.getText()+str);

}

}

else {

str=Character.toString(e.getKeyChar());

tf.setText(str);

enable=true;

}

}

if(e.getKeyCode()==KeyEvent.VK_ENTER){

switch(code){

case 0:

y=x+Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

case 1:

y=x-Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

case 2:

y=x*Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

case 3:

y=x/Float.parseFloat(this.tf.getText());

tf.setText(Float.toString(y));

enable=false;

break;

}

}

}

public void keyReleased(KeyEvent arg0) {

// TODO Auto-generated method stub

}

public void keyTyped(KeyEvent arg0) {

// TODO Auto-generated method stub

}

}