Android simple calculator

Note: When the input is empty, a dialog box prompt is displayed, indicating that no number is entered. When the divisor is 0, a prompt is displayed, indicating that the divisor cannot be blank. after entering a number, click the plus, subtraction, multiplication, division, and operation button to perform the operation. After you click the menu, the "about" and "exit" button appear at the bottom of the screen. Click "About". The "about" dialog box appears. Click "exit" to exit the program.

1. layout, activity_main.xml code:

<Linearlayout xmlns: Android = "http://schemas.android.com/apk/res/android" Android: layout_width = "fill_parent" Android: layout_height = "wrap_content" Android: gravity = "center_vertical" Android: orientation = "vertical"> <relativelayout Android: Id = "@ + ID/relative1" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content"> <! -- The first number involved in the calculation --> <edittext Android: Id = "@ + ID/num1" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_alignparentleft = "true" Android: layout_margintop = "10dp" Android: EMS = "4" Android: inputtype = "Number"> <requestfocus/> </edittext> <! -- Operator number --> <textview Android: Id = "@ + ID/fuhao" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_margintop = "15dp" Android: layout_torightof = "@ ID/num1" Android: padding = "@ dimen/padding_medium" Android: text = "@ string/fuhao"/> <! -- The second number involved in the calculation --> <edittext Android: Id = "@ + ID/num2" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_margintop = "10dp" Android: layout_torightof = "@ ID/fuhao" Android: EMS = "4" Android: inputtype = "Number"/> <! -- Equal sign --> <textview Android: Id = "@ + ID/denghao" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_margintop = "15dp" Android: layout_torightof = "@ ID/num2" Android: padding = "@ dimen/padding_medium" Android: text = "@ string/denghao"/> <! -- Result --> <textview Android: Id = "@ + ID/result" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_margintop = "15dp" Android: layout_torightof = "@ ID/denghao" Android: padding = "@ dimen/padding_medium" Android: text = "@ string/result"/> </relativelayout> <relativelayout Android: layout_width = "wrap_content" Android: layout_height = "wrap_content"> <! -- Plus sign --> <button Android: Id = "@ + ID/Add" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_alignparentleft = "true" Android: layout_centerhorizontal = "true" Android: EMS = "4" Android: text = "@ string/Add"/> <! -- Minus sign --> <button Android: Id = "@ + ID/Sub" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_centerhorizontal = "true" Android: layout_torightof = "@ ID/Add" Android: EMS = "4" Android: text = "@ string/Sub"/> <! -- Multiplication --> <button Android: Id = "@ + ID/mult" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_centerhorizontal = "true" Android: layout_torightof = "@ ID/Sub" Android: EMS = "4" Android: text = "@ string/mult"/> <! -- Divisor --> <button Android: Id = "@ + ID/divid" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_torightof = "@ ID/mult" Android: EMS = "4" Android: text = "@ string/divid"/> </relativelayout> <relativelayout Android: layout_width = "wrap_content" Android: layout_height = "wrap_content"> <! -- About buttons --> <button Android: Id = "@ + ID/about" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: TEXT = "@ string/about"/> <! -- Exit button --> <button Android: Id = "@ + ID/quit" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: TEXT = "@ string/quit"/> </relativelayout> </linearlayout>
2. mainactivity. Java code:
Package CN. BZU. case1; import Java. text. decimalformat; import CN. BZU. model. calculatorbiz; import android. OS. bundle; import android. app. activity; import android. app. alertdialog; import android. view. menu; import android. view. menuitem; import android. view. view; import android. view. view. onclicklistener; import android. widget. button; import android. widget. edittext; import android. widget. textview; import android. widge T. toast; import android. widget. remoteviews. actionexception; import android. support. v4.app. navutils; public class mainactivity extends activity {private double number1, number2; private edittext num1, num2; private textview result, fuhao; private button add, sub, mult, divid, quit, about; calculatorbiz calculator; @ overridepublic void oncreate (bundle savedinstancestate) {super. oncreate (savedinstancestate ); Setcontentview (R. layout. activity_main); num1 = (edittext) This. findviewbyid (R. id. num1); num2 = (edittext) This. findviewbyid (R. id. num2); add = (button) This. findviewbyid (R. id. add); sub = (button) This. findviewbyid (R. id. sub); mult = (button) This. findviewbyid (R. id. mult); divid = (button) This. findviewbyid (R. id. divid); fuhao = (textview) This. findviewbyid (R. id. fuhao); Result = (textview) This. findviewbyid (R. Id. result); quit = (button) This. findviewbyid (R. id. quit); about = (button) This. findviewbyid (R. id. about); quit. setvisibility (view. invisible); about. setvisibility (view. invisible); add. setonclicklistener (New calculatorclicklistener (); sub. setonclicklistener (New calculatorclicklistener (); mult. setonclicklistener (New calculatorclicklistener (); divid. setonclicklistener (New calculatorclicklistener ();} privat E Class calculatorclicklistener implements onclicklistener {@ overridepublic void onclick (view v) {// If edittext is empty if (num1.gettext (). tostring (). specified signorecase ("") {toast. maketext (mainactivity. this, "No number entered! ", Toast. length_short ). show ();} else if (num2.gettext (). tostring (). specified signorecase ("") {toast. maketext (mainactivity. this, "No number entered! ", Toast. length_short ). show ();} else {number1 = double. parsedouble (num1.gettext (). tostring (); number2 = double. parsedouble (num2.gettext (). tostring (); If (v. equals (ADD) {result. settext (number1 + number2 + ""); fuhao. settext ("+");} If (v. equals (sub) {result. settext (number1-number2 + ""); fuhao. settext ("-");} If (v. equals (mult) {result. settext (number1 * number2 + ""); fuhao. settext ("*");} If (v. equals (Divid) {If (number2 = 0) {toast. maketext (mainactivity. This, "the divisor cannot be zero! ", Toast. length_short ). show ();} else {result. settext (number1/number2 + ""); fuhao. settext ("/") ;}}}}@ overridepublic Boolean oncreateoptionsmenu (menu) {super. oncreateoptionsmenu (menu); // create a menu, set the icon, and use the icon provided by the system, menu. add (0, R. id. about, 0, "about "). seticon (Android. r. drawable. ic_dialog_info); menu. add (0, R. id. quit, 1, "quit "). seticon (Android. r. drawable. ic_lock_power_off); menu. finditem (R. id. quit); // return true, that is Show menu return true;} @ override // response menu Click Event, public Boolean onoptionsitemselected (menuitem item) {Switch (item. getitemid () {case R. id. about: // about alertdialog. builder dialog = new alertdialog. builder (this); dialog. settitle ("about"); dialog. setmessage ("Easy calculator! \ N Author: vivy \ n version: 1.0 "); dialog. show (); break; case R. id. quit: // exit this. finish (); break;} return Super. onoptionsitemselected (item );}}
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