Android Development Implementation Calculator example

Example

The code is as follows

Copy Code

<linearlayout xmlns:android= "Http://schemas.android.com/apk/res/android" Android:id= "@+id/warpcontent" Android:layout_width= "Fill_parent" android:layout_height= "Fill_parent" android:orientation= "Vertical" > Android:id= "@+id/scrollview" Android:layout_width= "Fill_parent" android:layout_height= "Wrap_content" > &lt;textview Android:id= "@+id/resulttext" Android:layout_width= "Wrap_content" android:layout_height= "Wrap_content" Android:layout_gravity= "Right" Android:gravity= "Right" Android:padding= "8DP" android:paddingleft= "10DP" android:paddingright= "10DP" android:text= "@string/number0" Android:textsize= "40sp"/&gt; &lt;/horizontalscrollview &gt; <tablelayout Android:id= "@+id/buttontable" Android:layout_width= "Fill_parent" android:layout_height= "0DP" android:layout_weight= "1" android:stretchcolumns= "*" >         <tablerow              android:layout_width= "Fill_parent"              android:layout_height= "0DP"             android:layout_weight= "1"             <button                  android:id= "@+id/button7"                  android:layout_width= "Wrap_ Content "                 android: layout_height= "Fill_parent"                  android:onclick= "Onclicklistener"                  android:text= "@string/number7"/>             <button                  android:id= "@+id/button8"                  android:layout_width= "Wrap_ Content "                 android: layout_height= "Fill_parent"                  android:onclick= "Onclicklistener"                  android:text= "@string/number8"/>             <button                  android:id= "@+id/button9"                  android:layout_width= "Wrap_ Content "                 android: layout_height= "Fill_parent"                  android:onclick= "Onclicklistener"                  android:text= "@string/number9"/>             <button                  android:id= "@+id/buttonbackspace"                  android:layout_width= "Wrap _content "                 Android : layout_height= "fill_parent"                  android:onclick= "Onclicklistener"                  android:text= "@string/backspace"/>             <button                  android:id= "@+id/buttonclear"                  android:layout_width= "Wrap _content "                 Android : layout_height= "fill_parent"                  android:onclick= "Onclicklistener"                  android:text= "@string/clear"/>         </tablerow>         <tablerow              android:layout_width= "Fill_parent"              android:layout_height= "0DP"             android:layout_weight= "1"             <button                  android:id= "@+id/button4"                  android:layout_width= "Wrap_ Content "                 android: layout_height= "Fill_parent"                  android:onclick= "Onclicklistener"                  android:text= "@string/number4"/>             <button                  android:id= "@+id/button5"                  android:layout_width= "Wrap_ Content "                 android: layout_height= "Fill_parent"                  android:onclick= "Onclicklistener"                  android:text= "@string/number5"/>             <button                  android:id= "@+id/button6"                  android:layout_width= "Wrap_ Content "                 android: layout_height= "Fill_parent"                  android:onclick= "Onclicklistener"                  android:text= "@string/number6"/>             <button                  android:id= "@+id/buttonmultiply"                  android:layout_width= "Wrap _content "                 Android : layout_height= "fill_parent"                  android:onclick= "Onclicklistener"                  android:text= "@string/multiply"/>             <button                  android:id= "@+id/buttondivide"                  android:layout_width= "Wrap _content "                 Android : layout_height= "fill_parent"                  android:onclick= "Onclicklistener"                  android:text= "@string/divide"/>         </tablerow>     </tablelayout> <linearlayout Android:layout_width= "Fill_parent" android:layout_height= "0DP" android:layout_weight= "1" android:orientation= "Horizontal" > <tablelayout Android:layout_width= "0DP" android:layout_height= "Fill_parent" android:layout_weight= "3" android:stretchcolumns= "*" >             <tablerow                  android:layout_width= "Fill_parent"                  android:layout_height= "0DP "                 Android:layout_ weight= "1"                 <button                      android:id= "@+id/button1"                      android:layout_width= "Wrap_content"                      Android:layout_ height= "Fill_parent"                      android:onclick= "Onclicklistener"                      android:text= "@string/number1"/>                 <button                      android:id= "@+id/button2"                      android:layout_width= "Wrap_content"                      Android:layout_ height= "Fill_parent"                      android:onclick= "Onclicklistener"                      android:text= "@string/number2"/>                 <button                      android:id= "@+id/button3"                      android:layout_width= "Wrap_content"                      Android:layout_ height= "Fill_parent"                      android:onclick= "Onclicklistener"                      android:text= "@string/number3"/>             </tablerow>             <tablerow                  android:layout_width= "Fill_parent"                  android:layout_height= "0DP "                 Android:layout_ weight= "1"                 <button                      android:id= "@+id/button0"                      android:layout_width= "Wrap_content"                      Android:layout_ height= "Fill_parent"                      android:onclick= "Onclicklistener"                      android:text= "@string/number0"/> <button Android:id= "@+id/buttondot" Android:layout_width= "Wrap_content" android:layout_height= "Fill_parent" android:onclick= "Onclicklistener" android:text= "@string/dot"/> &lt;button Android:id= "@+id/buttonnegsign" Android:layout_width= "Wrap_content" android:layout_height= "Fill_parent" android:onclick= "Onclicklistener" android:text= "@string/negsign"/&gt; &lt;/TableRow&gt; &lt;/TableLayout&gt; <button Android:id= "@+id/buttonplus" Android:layout_width= "0DP" android:layout_height= "Fill_parent" android:layout_weight= "1" android:onclick= "Onclicklistener" android:text= "@string/plus"/>         <linearlayout              android:layout_width= "0DP"              android:layout_height= "Fill_parent"              android:layout_weight= "1"             android:orientation= "Vertical"             <button                  android:id= "@+id/buttonminus"                  android:layout_width= "Fill _parent "                 android: layout_height= "0DP"                  android:layout_weight= "1"                  android:onclick= "Onclicklistener"                  android:text= "@string/minus"/> <button Android:id= "@+id/buttoneval" Android:layout_width= "Fill_parent" android:layout_height= "0DP" android:layout_weight= "1" android:onclick= "Onclicklistener" android:text= "@string/eval"/> </LinearLayout> </LinearLayout> </LinearLayout>

The Mainactivity class is similar to the previous Java calculator:

The code is as follows

Copy Code

Package Me.jerrys.calc; Import Java.math.BigDecimal; Import android.support.v7.app.ActionBarActivity; Import Android.app.AlertDialog; Import Android.os.Bundle; Import Android.view.Menu; Import Android.view.MenuItem; Import Android.view.View; Import Android.widget.TextView; Import Android.widget.Toast; public class Mainactivity extends Actionbaractivity { Private TextView TextView; Private BigDecimal Lastnum = new BigDecimal ("0"); Private BigDecimal Currentnum = new BigDecimal ("0"); Private String Currenttext; Private Boolean Typeclean = false; Private Boolean hadcalced = false; Private mode CurrentMode = mode. PLUS; Private enum MODE { PLUS, minus, MULTIPLY, DIVIDE } @Override protected void OnCreate (Bundle savedinstancestate) { Super.oncreate (savedinstancestate); Setcontentview (R.layout.activity_main); TextView = (TextView) Findviewbyid (R.id.resulttext); } @Override public boolean Oncreateoptionsmenu (Menu menu) { Getmenuinflater (). Inflate (R.menu.main, menu); return true; } public void Onclicklistener (View v) { Currenttext = Textview.gettext (). toString (); Switch (V.getid ()) { Case R.ID.BUTTON0: Addnumber ("0"); Break Case R.id.button1: Addnumber ("1"); Break Case R.id.button2: Addnumber ("2"); Break Case R.ID.BUTTON3: Addnumber ("3"); Break Case R.ID.BUTTON4: Addnumber ("4"); Break Case R.ID.BUTTON5: Addnumber ("5"); Break Case R.ID.BUTTON6: Addnumber ("6"); Break Case R.ID.BUTTON7: Addnumber ("7"); Break Case R.ID.BUTTON8: Addnumber ("8"); Break Case R.ID.BUTTON9: Addnumber ("9"); Break Case R.id.buttonnegsign: Addsign (); Break Case R.id.buttonclear: Clear (); Break Case R.id.buttonbackspace: BackSpace (); Break Case R.id.buttonplus: SetMode (MODE. PLUS); Break Case R.id.buttonminus: SetMode (MODE. Minus); Break Case R.id.buttonmultiply: SetMode (MODE. MULTIPLY); Break Case R.id.buttondivide: SetMode (MODE. DIVIDE); Break Case R.id.buttoneval: Calc (); Break Case R.ID.BUTTONDOT: Addnumber ("."); Break } } private void Calc () { if (hadcalced && Typeclean) return; Currentnum = new BigDecimal (currenttext); try { Switch (currentmode) { Case PLUS: Lastnum = Lastnum.add (currentnum); Break Case minus: Lastnum = Lastnum.subtract (currentnum); Break Case MULTIPLY: Lastnum = lastnum.multiply (currentnum); Break Case DIVIDE: Lastnum = Lastnum.divide (Currentnum, 16, Bigdecimal.round_half_down); Break } catch (Exception e) { Toast.maketext (Getapplicationcontext (), "Error occurred:" +e.getmessage (), Toast.length_short). Show (); Return } String Resulttext = lastnum.tostring (); if (Resulttext.indexof (".") > 0) {//elimination of decimal extra digits Resulttext = Resulttext.replaceall ("0+?$", ""); Resulttext = Resulttext.replaceall ("[.] $", ""); } Setresulttext (Resulttext); Typeclean = true; hadcalced = false; } private void SetMode (Mode mode) { if (!hadcalced &&!typeclean) { Calc (); CurrentMode = mode; Return } Lastnum = new BigDecimal (currenttext); CurrentMode = mode; Typeclean = true; hadcalced = true; } private void Addsign () { if (Currenttext.equals ("0") | | currenttext.equals ("")) return; if (Currenttext.startswith ("-")) Setresulttext (currenttext.substring (1)); Else Setresulttext ("-" + currenttext); } private void Clear () { Currentnum = new BigDecimal ("0"); Lastnum = new BigDecimal ("0"); Typeclean = false; CurrentMode = MODE. PLUS; Setresulttext ("0"); } private void Setresulttext (string string) { Textview.settext (string); } public void Addnumber (String num) { String resulttext = Currenttext; if (Typeclean = = True) { Resulttext = "0"; Typeclean = false; } if (Num.equals (".") && Currenttext.lastindexof (".")!=-1) return; if ((Resulttext.equals ("0") | | resulttext.equals ("")) &&!num.equals (".")) Resulttext = ""; Resulttext = Resulttext + num; Setresulttext (Resulttext); } private void BackSpace () { if (Currenttext.equals ("0") | | currenttext.equals ("")) return; if (currenttext.length () = = 1) { Setresulttext ("0"); Return } Setresulttext (currenttext.substring (0, Currenttext.length ()-1)); } @Override public boolean onoptionsitemselected (MenuItem item) { if (item.getitemid () = = R.id.action_about) { New Alertdialog.builder (this). Settitle ("about"). Setmessage ("" Android www.111cn.net Simple Calculator "n Author jerrylocken blog n Source code/ Android-simple-calc "). Setpositivebutton (" OK ", null). Show (); return true; } return super.onoptionsitemselected (item); } }