Swing Implementation Calculator

The code is as follows

Import Java.awt.*;import java.awt.event.*;import Javax.swing.*;import Java.util.vector;public class Calculator {Strin G str1 = "0"; Operand 1 Initial value must be 0 for program security String str2 = "0"; Operand 2 String signal = "+"; Operator String result = "";//result//status switch int k1 = 1;//switch 1 used to select input direction to be written to str2 or str2 int k2 = 1;//Switch 2 sign key number k2& Gt;1 instructions are 2+3-9+8 such a multi-sign operation int K3 = 1;//Switch 3 str1 can be cleared 0 ==1 when!=1 can not be cleared 0 int K4 = 1;//Switch 4 str2 Ibid int K5 = 1;/ /Switch 5 control the decimal point can be entered ==1!=1 input decimal point is discarded JButton store;    Register record whether the symbol key is pressed continuously @SuppressWarnings ("rawtypes") vector vt = new vector (20, 10);    JFrame frame = new JFrame ("Calculator");    JTextField Result_textfield = new JTextField (result, 20);//20 columns JButton Clear_button = new JButton ("clear");    JButton button0 = new JButton ("0");    JButton button1 = new JButton ("1");    JButton button2 = new JButton ("2");    JButton Button3 = new JButton ("3");    JButton button4 = new JButton ("4");    JButton button5 = new JButton ("5"); JButton button6 = new JButton ("6");    JButton button7 = new JButton ("7");    JButton button8 = new JButton ("8");    JButton Button9 = new JButton ("9");    JButton Button_dian = new JButton (".");    JButton Button_jia = new JButton ("+");    JButton Button_jian = new JButton ("-");    JButton Button_cheng = new JButton ("*");    JButton Button_chu = new JButton ("/");    JButton button_dy = new JButton ("="); Calculator () {button0.setmnemonic (KEYEVENT.VK_0);//equivalent key//other equivalent key, Result_textfield.sethorizontala        Lignment (jtextfield.right);//text box right-aligned JPanel pan = new JPanel ();        Pan.setlayout (New GridLayout (4, 4, 5, 5));//Four rows four row margin is 5 pixels pan.add (button7);        Pan.add (BUTTON8);        Pan.add (BUTTON9);        Pan.add (Button_chu);        Pan.add (BUTTON4);        Pan.add (BUTTON5);        Pan.add (BUTTON6);        Pan.add (Button_cheng);        Pan.add (button1);        Pan.add (button2);        Pan.add (Button3);        Pan.add (Button_jian);        Pan.add (Button0); PAn.add (Button_dian);        Pan.add (Button_dy);        Pan.add (Button_jia);        Pan.setborder (Borderfactory.createemptyborder (5, 5, 5, 5));//Pan object margin JPanel pan2 = new JPanel ();        Pan2.setlayout (New BorderLayout ());        Pan2.add (Result_textfield, borderlayout.west);        Pan2.add (Clear_button, borderlayout.east); Frame.setlocation (300, 200); The main window appears in position frame.setresizable (false);        Cannot adjust size frame.getcontentpane (). setlayout (New BorderLayout ());        Frame.getcontentpane (). Add (pan2, Borderlayout.north);        Frame.getcontentpane (). Add (pan, borderlayout.center);        Frame.pack ();        Frame.setvisible (TRUE);            Event handler//numeric key class Listener implements ActionListener {@SuppressWarnings ("unchecked")                public void actionperformed (ActionEvent e) {String SS = ((JButton) E.getsource ()). GetText ();                store = (JButton) e.getsource ();             Vt.add (store);   if (k1 = = 1) {if (K3 = = 1) {str1 = "";                    K5 = 1;//restore switch K5 status} str1 = str1 + ss;                    K3 = K3 + 1;                        Result_textfield.settext (STR1);//display} else if (k1 = = 2) {if (K4 = = 1) {                        STR2 = ""; K5 = 1;                    Restore switch K5 status} str2 = str2 + ss;                    K4 = K4 + 1;                Result_textfield.settext (STR2); }}}//Symbol class Listener_signal implements ActionListener {@SuppressWarning S ("unchecked") public void actionperformed (ActionEvent e) {String SS2 = ((JButton) E.getsource (                ). GetText ();                store = (JButton) e.getsource ();                Vt.add (store);    if (K2 = = 1) {k1 = 2;//switch K1 is 1 o'clock, number 1 writes to 2 o'clock, writes to number 2                K5 = 1;                    signal = SS2;                    K2 = K2 + 1;//by the number of symbol keys} else {int a = Vt.size ();                    JButton C = (JButton) vt.get (a-2); if (! ( C.gettext (). Equals ("+")) &&! (C.gettext (). Equals ("-")) &&! (C.gettext (). Equals ("*")) &&!                    (C.gettext (). Equals ("/")))                        {cal ();                        STR1 = result;                        K1 = 2;//switch K1 is 1 o'clock, to the number 1 written as 2 o'clock, to the number 2 write K5 = 1;                        K4 = 1;                    signal = SS2;                } K2 = k2 + 1; }}}//Clear class Listener_clear implements ActionListener {@SuppressWarnings ( "Unchecked") public void actionperformed (ActionEvent e) {store = (JButton)E.getsource ();                Vt.add (store);                K5 = 1;                K2 = 1;                K1 = 1;                K3 = 1;                K4 = 1;                STR1 = "0";                STR2 = "0";                signal = "";                result = "";                Result_textfield.settext (result);            Vt.clear ();            }}//Equals class Listener_dy implements ActionListener {@SuppressWarnings ("unchecked")                public void actionperformed (ActionEvent e) {store = (JButton) e.getsource ();                Vt.add (store);                Cal (); K1 = 1;                Reset switch K1 status//Str1=result;                K2 = 1; K3 = 1;//restore switch K3 status K4 = 1; Reset switch K4 Status str1 = result;            Prepare for 7+5=12 +5=17 This calculation}}//Decimal class Listener_xiaos implements ActionListener { @SuppressWarnings ("unchecked") public VOID actionperformed (ActionEvent e) {store = (JButton) e.getsource ();                Vt.add (store);                    if (K5 = = 1) {String SS2 = ((JButton) E.getsource ()). GetText ();                            if (k1 = = 1) {if (K3 = = 1) {str1 = ""; K5 = 1;                        Restore switch K5 status} str1 = str1 + ss2;                        K3 = K3 + 1;                            Result_textfield.settext (STR1);//display} else if (k1 = = 2) {if (K4 = = 1) {                            STR2 = ""; K5 = 1;                        Restore switch K5 status} str2 = str2 + ss2;                        K4 = K4 + 1;                    Result_textfield.settext (STR2);            }} K5 = K5 + 1; }}//Register listener Listener_dy Jt_dy = new Listener_DY (); Listener JT = new Listener ()//pro-listening number key listener_signal jt_signal = new listener_signal ();//pro-listening symbol key Listener_ Clear Jt_c = new Listener_clear ();        Clear key Listener_xiaos Jt_xs = new Listener_xiaos ();//Decimal Key Button7.addactionlistener (JT);        Button8.addactionlistener (JT);        Button9.addactionlistener (JT);        Button_chu.addactionlistener (jt_signal);        Button4.addactionlistener (JT);        Button5.addactionlistener (JT);        Button6.addactionlistener (JT);        Button_cheng.addactionlistener (jt_signal);        Button1.addactionlistener (JT);        Button2.addactionlistener (JT);        Button3.addactionlistener (JT);        Button_jian.addactionlistener (jt_signal);        Button0.addactionlistener (JT);        Button_dian.addactionlistener (JT_XS);        Button_dy.addactionlistener (Jt_dy);        Button_jia.addactionlistener (jt_signal);        Clear_button.addactionlistener (Jt_c); Shutdown event handler Frame.addwindowlistener (new WIndowadapter () {public void windowclosing (WindowEvent e) {system.exit (0);    }        });        }//Calculate public void cal () {Double a2;//operand 1 double b2;//operand 2 String c = signal;//operator        Double RESULT2 = 0;//result if (C.equals ("")) {Result_textfield.settext ("enter operator");            } else {if (Str1.equals ("."))///string "." Error when converting to double type data so manual turn str1 = "0.0";                if (Str2.equals ("."))            str2 = "0.0";            A2 = double.valueof (str1). Doublevalue ();            B2 = double.valueof (str2). Doublevalue ();            if (c.equals ("+")) {result2 = a2 + b2;            } if (C.equals ("-")) {result2 = A2-B2;            } if (C.equals ("*")) {result2 = a2 * B2;                } if (C.equals ("/")) {if (B2 = = 0) {result2 = 0;               } else {     RESULT2 = A2/B2;            }} result = ((New Double (RESULT2)). toString ());        Result_textfield.settext (result);                    }} @SuppressWarnings ("unused") public static void main (string[] args) {//interface style, you can remove try {        Uimanager.setlookandfeel ("Com.sun.java.swing.plaf.windows.WindowsLookAndFeel");        } catch (Exception e) {e.printstacktrace ();    } Calculator cal = new Calculator (); }}

Detailed instructions in the Java Tutorial Web

Swing Implementation Calculator