JAVA實作Calculator(電腦)

package swing;

import java.awt.Container;

import java.awt.GridLayout;

/*GridLayout 類是一個布局處理器，它以矩形網格形式對容器的元件進行布置。容器被分成大小相等的矩形，一個矩形中放置一個元件*/

import java.awt.BorderLayout;

/*BorderLayout是一個布置容器的邊界布局，它可以對容器元件進行安排，并調整其大小，使其符合下列五個區域：南、北、東、西和中間區域。每個區域最多隻能包含一個元件，并通過相應的常量進行辨別：NORTH、SOUTH、EAST、WEST 和 CENTER。當使用邊界布局将一個元件添加到容器中時，要使用這五個常量之一*/

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);//設定文本的水準對齊方式

         jtf.setLayout(new GridLayout());

        c.add(jtf,BorderLayout.NORTH);//

        JPanel jp = new JPanel();

        jp.setLayout(new GridLayout(4,4));//對于GridLayout(int rows,int cols)詳情請參見API

        c.add(jp,BorderLayout.CENTER);/*這裡剛開始犯了一低級錯誤，将c寫成了jp，邏輯調用都出現了問題*/

        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);

            jp.add(ja[i]);

            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.temp = 2;

        else if(s.equals("*")){

            this.temp = 3;

        else if(s.equals("/")){

            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;

                case 3:

                    result = fnumber * bnumber;

                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();

}