Java Learning--Calculator Applet

Simple Calculator Small program code:

Package jisuanqi;//declares that a packet needs to be inserted import Java.awt.*;import java.lang.object;import java.lang.string;import javax.swing.*; Import Java.awt.event.*;import java.awt.textcomponent;//declares a main class Jisuanqi, continuation window class Framepublic class Jisuanqi extends Frame  {//Declaration of 16 Buttonbutton Anjian1, Anjian2, Anjian3, Anjian4, Anjian5, Anjian6, Anjian7, Anjian8, Anjian9, Anjian10, Anjian11, Anjian12, ANJIAN13, anjian14,anjian15,anjian16;//Declaration text box, used to receive numbers and calculate TextField numtext;//Declarations panel container, for holding various buttons for panel anjianpanel;//constructor Method initializes the button Jisuanqi (String title) {Super (title), Anjian1=new button ("0"), Anjian2=new button ("1"); Anjian3=new button ("2"), Anjian4=new button ("3"), Anjian5=new button ("4"), Anjian6=new button ("5"), Anjian7=new button ( "6"), Anjian8=new button ("7"), Anjian9=new button ("8"), Anjian10=new button ("9"), Anjian11=new button ("+"); anjian12= New Button ("-"); Anjian13=new button ("*"); Anjian14=new button ("/"); Anjian15=new button ("="); anjian16=new button ("Empty" );//Initialize the text box, set the value of the text to "0" numtext=new TextField ("0");//instantiate panel; anjianpanel=new panels ();//Set Button ANJIANPAnel.setlayout (New FlowLayout ());//Instantiate button Anjian1.addactionlistener (new Anjianaction ()); Anjian2.addactionlistener ( New Anjianaction ()); Anjian3.addactionlistener (new Anjianaction ()); Anjian4.addactionlistener (new Anjianaction ()); Anjian5.addactionlistener (New Anjianaction ()); Anjian6.addactionlistener (new Anjianaction ()); Anjian7.addactionlistener (New Anjianaction ()); Anjian8.addactionlistener (new Anjianaction ()); Anjian9.addactionlistener (New Anjianaction ()); Anjian10.addactionlistener (new Anjianaction ()); Anjian11.addactionlistener (New Anjianaction ()); Anjian12.addactionlistener (new Anjianaction ()); Anjian13.addactionlistener (New Anjianaction ()); Anjian14.addactionlistener (new Anjianaction ()); Anjian15.addactionlistener (New Anjianaction ()); Anjian16.addactionlistener (new Anjianaction ());// Add individual buttons to the Panel container Anjianpanel.add (anjian1); Anjianpanel.add (anjian2); Anjianpanel.add (ANJIAN3); Anjianpanel.add ( ANJIAN4); Anjianpanel.add (ANJIAN5); Anjianpanel.add (anjian6); Anjianpanel.add (ANJIAN7); Anjianpanel.add (ANJIAN8); AnJianpanel.add (ANJIAN9); Anjianpanel.add (ANJIAN10); Anjianpanel.add (anjian11); Anjianpanel.add (ANJIAN12); Anjianpanel.add (ANJIAN13); Anjianpanel.add (ANJIAN14); Anjianpanel.add (anjian15); Anjianpanel.add (Anjian16);// Add Event Numtext.addtextlistener (new TextListener () {public void textvaluechanged (TextEvent e) {if (Numtext.gettext ()) for the text box. IndexOf ("0", 0)!=-1) {Numtext.gettext (). Replace ("0", "");}}); Addwindowlistener (New Windowadapter () {public void windowclosing (WindowEvent e) {system.exit (0);}}); /Place the text box at the top of Add (Numtext,borderlayout.north);//Add a button (anjianpanel,borderlayout.center);// Sets the text Box property numtext.seteditable (FALSE);} The value of no action int num=0;//numstr is the value of the text box string numstr=null; The Boolean chinage=false;//setting button public int check () {numstr = Numtext.gettext (); if (Numstr.indexof ("+") = = 0) {numstr = Numstr. Replace (' + ', ' 0 '); num = num + integer.parseint (NUMSTR); return num;} else if (Numstr.indexof ("-")! =-1) {numstr = Numstr.replace ("-", "0"); num = Num-integer.parseint (NUMSTR); return num;} else if (Numstr.indexof ("*")!=-1) {nUmstr=numstr.replace (' * ', ' 0 '); num = num * Integer.parseint (NUMSTR); return num;} else if (Numstr.indexof ("/")!=-1) {numstr=numstr.replace ('/', ' 0 '); try{num = Num/integer.parseint (NUMSTR); return num;} catch (ArithmeticException e) {joptionpane.showmessagedialog (null, "divisor cannot be empty!", "Message!", 1); return num;}} else return Num=integer.parseint (NUMSTR);} Create event Private class Anjianaction implements Actionlistener{public void Actionperformed (ActionEvent event) {if ( Event.getactioncommand () = = "0") {if (!numtext.gettext (). Equals ("0")) Numtext.settext (Numtext.gettext () +0);} if (event.getactioncommand () = = "1") Numtext.settext (Numtext.gettext () +1); if (event.getactioncommand () = = "2") Numtext.settext (Numtext.gettext () +2), if (event.getactioncommand () = = "3") Numtext.settext (Numtext.gettext () +3); Event.getactioncommand () = = "4") Numtext.settext (Numtext.gettext () +4); if (event.getactioncommand () = = "5") Numtext.settext (Numtext.gettext () +5), if (event.getactioncommand () = = "6") Numtext.settext (Numtext.gettext () +6); Event.getactioncommand () = = "7") nUmtext.settext (Numtext.gettext () +7), if (event.getactioncommand () = = "8") Numtext.settext (Numtext.gettext () +8); Event.getactioncommand () = = "9") Numtext.settext (Numtext.gettext () +9); if (event.getactioncommand () = = "Empty") { Numtext.settext ("0"); num=0;} if (event.getactioncommand () = = "+") {//call check (); method Check (); Numtext.settext ("+");} if (event.getactioncommand () = = "-") {check (); Numtext.settext ("-");} if (event.getactioncommand () = = "*") {check (); Numtext.settext ("*");} if (event.getactioncommand () = = "/") {if (numstr== "/0") {Joptionpane.showmessagedialog (null, "divisor cannot be empty!", "Message!", 1);} Check (); Numtext.settext ("/");} if (event.getactioncommand () = = "=") {check (); Numtext.settext ("" +num);}}} public static void Main (string[] args) {Jisuanqi jisuanqi=new Jisuanqi ("calculator"); Jisuanqi.setbackground (Color.cyan); Jisuanqi.setsize (300,280);//Set Window size jisuanqi.setlocation (550,350);//Set interface property jisuanqi.setvisible (TRUE);}}

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Java Learning--Calculator Applet