JAVA实现Calculator(计算器)

package swing;

import java.awt.Container;
import java.awt.GridLayout;
/*GridLayout 类是一个布局处理器，它以矩形网格形式对容器的组件进行布置。容器被分成大小相等的矩形，一个矩形中放置一个组件*/
import java.awt.BorderLayout;
/*BorderLayout是一个布置容器的边界布局，它可以对容器组件进行安排，并调整其大小，使其符合下列五个区域：南、北、东、西和中间区域。每个区域最多只能包含一个组件，并通过相应的常量进行标识：NORTH、SOUTH、EAST、WEST 和 CENTER。当使用边界布局将一个组件添加到容器中时，要使用这五个常量之一*/
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

/**
*
* @author Administrator
*/
public class Cal extends JFrame implements ActionListener {
JFrame jf;
JTextField jtf;
String[] b = new String[] {"+","-","*","/","."};
JButton jis = new JButton("=");
private int temp = 0;
private float result = 0;
private float fnumber = 0, bnumber = 0;

public Cal(){
init();
}

public void init(){
jf = new JFrame();
jtf = new JTextField();

Container c = jf.getContentPane();//Returns the contentPane object for this frame.
jtf.setHorizontalAlignment(JTextField.RIGHT);//设置文本的水平对齐方式
jtf.setLayout(new GridLayout());
c.add(jtf,BorderLayout.NORTH);//

JPanel jp = new JPanel();
jp.setLayout(new GridLayout(4,4));//对于GridLayout(int rows,int cols)详情请参见API
c.add(jp,BorderLayout.CENTER);/*这里刚开始犯了一低级错误，将c写成了jp，逻辑调用都出现了问题*/

JButton[] ja = new JButton[10];
JButton[] jb = new JButton[5];
for(int i = 0; i < 10; i++){
ja[i] = new JButton("" + i);
ja[i].addActionListener(this);
}
for(int j = 0; j < 5; j++){
jb[j] = new JButton("" + b[j]);
jb[j].addActionListener(this);
}

for(int i = 0; i < 10; i++){
jp.add(ja[i]);
}
for(int j = 0; j < 5; j++){
jp.add(jb[j]);
}

jp.add(jis);
jis.addActionListener(this);
jf.setSize(200,300);
jf.setVisible(true);
}

public void actionPerformed(ActionEvent e){
String s = e.getActionCommand();
if(s.equals("+")){
this.fnumber = Float.parseFloat(this.jtf.getText());
this.jtf.setText("");
this.temp = 1;
}
else if(s.equals("-")){
this.fnumber = Float.parseFloat(this.jtf.getText());
this.jtf.setText("");
this.temp = 2;
}
else if(s.equals("*")){
this.fnumber = Float.parseFloat(this.jtf.getText());
this.jtf.setText("");
this.temp = 3;
}
else if(s.equals("/")){
this.fnumber = Float.parseFloat(this.jtf.getText());
this.jtf.setText("");
this.temp = 4;
}
else if(s.equals(".")){
if(jtf.equals("")){
jtf.setText("0.");
}
else{
jtf.setText(jtf.getText() + ".");
}
}
else if(s.equals("=")){
this.bnumber = Integer.parseInt(this.jtf.getText());
switch(this.temp){
case 1:
result = fnumber + bnumber;
this.jtf.setText(String.valueOf(result));
break;
case 2:
result = fnumber - bnumber;
this.jtf.setText(String.valueOf(result));
break;
case 3:
result = fnumber * bnumber;
this.jtf.setText(String.valueOf(result));
break;
case 4:
result = fnumber / bnumber;
this.jtf.setText(String.valueOf(result));
break;
}
}
else{
jtf.setText(jtf.getText() + e.getActionCommand());
}
}

public static void main(String[] args){
new Cal();
}
}
本文出自 “mai” 博客，请务必保留此出处http://yangwen.blog.51cto.com/337928/98094