Android Tutorial: Calculator App Example with Java Code
For the source code relating to this post, checkout this Github repository.
A year ago I started going through the CS 193P iPhone Application Development.
The following code is a simple Android Calculator that I have converted from the work I did for the above online class. It was my starting point into android and it’s simple enough as it’s just one activity.
Create a new Android Application Project. Let’s say your Application Name is “Calculator”, your Project Name is “Calculator”, and your Package Name is “com.example.calculator”. Setup the project with the default settings. Now replace MainActivity.java, activity_main.xml (in res/layout), & strings.xml (in res/values) with the code below. Next, create a new class “CalculatorBrain” and replace CalculatorBrain.java with the code below. Finally, create a new xml file “activity_main” (in res/layout-land) (yes, you will have to create the folder too.) and replace activity_main.xml (in res/layout-land) with the code below. Make sure your package names are changed from “com.himebaugh.calculator” to “com.example.calculator” (or whatever your package is).
The calculator should run without errors! When you rotate the android device, the screen will change to display additional keys for operations like cosine and square root.
Download this Free Calculator App from the Google Play Store
@ https://play.google.com/store/apps/details?id=com.himebaugh.calculator
Good Luck & Enjoy!
MainActivity.java
package com.himebaugh.calculator;
import java.text.DecimalFormat;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity implements OnClickListener {
private TextView mCalculatorDisplay;
private Boolean userIsInTheMiddleOfTypingANumber = false;
private CalculatorBrain mCalculatorBrain;
private static final String DIGITS = "0123456789.";
DecimalFormat df = new DecimalFormat("@###########");
@SuppressLint("NewApi")
@Override
protected void onCreate(Bundle savedInstanceState) {
// hide the window title.
requestWindowFeature(Window.FEATURE_NO_TITLE);
// hide the status bar and other OS-level chrome
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mCalculatorBrain = new CalculatorBrain();
mCalculatorDisplay = (TextView) findViewById(R.id.textView1);
df.setMinimumFractionDigits(0);
df.setMinimumIntegerDigits(1);
df.setMaximumIntegerDigits(8);
findViewById(R.id.button0).setOnClickListener(this);
findViewById(R.id.button1).setOnClickListener(this);
findViewById(R.id.button2).setOnClickListener(this);
findViewById(R.id.button3).setOnClickListener(this);
findViewById(R.id.button4).setOnClickListener(this);
findViewById(R.id.button5).setOnClickListener(this);
findViewById(R.id.button6).setOnClickListener(this);
findViewById(R.id.button7).setOnClickListener(this);
findViewById(R.id.button8).setOnClickListener(this);
findViewById(R.id.button9).setOnClickListener(this);
findViewById(R.id.buttonAdd).setOnClickListener(this);
findViewById(R.id.buttonSubtract).setOnClickListener(this);
findViewById(R.id.buttonMultiply).setOnClickListener(this);
findViewById(R.id.buttonDivide).setOnClickListener(this);
findViewById(R.id.buttonToggleSign).setOnClickListener(this);
findViewById(R.id.buttonDecimalPoint).setOnClickListener(this);
findViewById(R.id.buttonEquals).setOnClickListener(this);
findViewById(R.id.buttonClear).setOnClickListener(this);
findViewById(R.id.buttonClearMemory).setOnClickListener(this);
findViewById(R.id.buttonAddToMemory).setOnClickListener(this);
findViewById(R.id.buttonSubtractFromMemory).setOnClickListener(this);
findViewById(R.id.buttonRecallMemory).setOnClickListener(this);
// The following buttons only exist in layout-land (Landscape mode) and require extra attention.
// The messier option is to place the buttons in the regular layout too and set android:visibility="invisible".
if (findViewById(R.id.buttonSquareRoot) != null) {
findViewById(R.id.buttonSquareRoot).setOnClickListener(this);
}
if (findViewById(R.id.buttonSquared) != null) {
findViewById(R.id.buttonSquared).setOnClickListener(this);
}
if (findViewById(R.id.buttonInvert) != null) {
findViewById(R.id.buttonInvert).setOnClickListener(this);
}
if (findViewById(R.id.buttonSine) != null) {
findViewById(R.id.buttonSine).setOnClickListener(this);
}
if (findViewById(R.id.buttonCosine) != null) {
findViewById(R.id.buttonCosine).setOnClickListener(this);
}
if (findViewById(R.id.buttonTangent) != null) {
findViewById(R.id.buttonTangent).setOnClickListener(this);
}
}
@Override
public void onClick(View v) {
String buttonPressed = ((Button) v).getText().toString();
if (DIGITS.contains(buttonPressed)) {
// digit was pressed
if (userIsInTheMiddleOfTypingANumber) {
if (buttonPressed.equals(".") && mCalculatorDisplay.getText().toString().contains(".")) {
// ERROR PREVENTION
// Eliminate entering multiple decimals
} else {
mCalculatorDisplay.append(buttonPressed);
}
} else {
if (buttonPressed.equals(".")) {
// ERROR PREVENTION
// This will avoid error if only the decimal is hit before an operator, by placing a leading zero
// before the decimal
mCalculatorDisplay.setText(0 + buttonPressed);
} else {
mCalculatorDisplay.setText(buttonPressed);
}
userIsInTheMiddleOfTypingANumber = true;
}
} else {
// operation was pressed
if (userIsInTheMiddleOfTypingANumber) {
mCalculatorBrain.setOperand(Double.parseDouble(mCalculatorDisplay.getText().toString()));
userIsInTheMiddleOfTypingANumber = false;
}
mCalculatorBrain.performOperation(buttonPressed);
mCalculatorDisplay.setText(df.format(mCalculatorBrain.getResult()));
}
}
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
// Save variables on screen orientation change
outState.putDouble("OPERAND", mCalculatorBrain.getResult());
outState.putDouble("MEMORY", mCalculatorBrain.getMemory());
}
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
// Restore variables on screen orientation change
mCalculatorBrain.setOperand(savedInstanceState.getDouble("OPERAND"));
mCalculatorBrain.setMemory(savedInstanceState.getDouble("MEMORY"));
mCalculatorDisplay.setText(df.format(mCalculatorBrain.getResult()));
}
}
CalculatorBrain.java
package com.himebaugh.calculator;
public class CalculatorBrain {
// 3 + 6 = 9
// 3 & 6 are called the operand.
// The + is called the operator.
// 9 is the result of the operation.
private double mOperand;
private double mWaitingOperand;
private String mWaitingOperator;
private double mCalculatorMemory;
// operator types
public static final String ADD = "+";
public static final String SUBTRACT = "-";
public static final String MULTIPLY = "*";
public static final String DIVIDE = "/";
public static final String CLEAR = "C" ;
public static final String CLEARMEMORY = "MC";
public static final String ADDTOMEMORY = "M+";
public static final String SUBTRACTFROMMEMORY = "M-";
public static final String RECALLMEMORY = "MR";
public static final String SQUAREROOT = "√";
public static final String SQUARED = "x²";
public static final String INVERT = "1/x";
public static final String TOGGLESIGN = "+/-";
public static final String SINE = "sin";
public static final String COSINE = "cos";
public static final String TANGENT = "tan";
// public static final String EQUALS = "=";
// constructor
public CalculatorBrain() {
// initialize variables upon start
mOperand = 0;
mWaitingOperand = 0;
mWaitingOperator = "";
mCalculatorMemory = 0;
}
public void setOperand(double operand) {
mOperand = operand;
}
public double getResult() {
return mOperand;
}
// used on screen orientation change
public void setMemory(double calculatorMemory) {
mCalculatorMemory = calculatorMemory;
}
// used on screen orientation change
public double getMemory() {
return mCalculatorMemory;
}
public String toString() {
return Double.toString(mOperand);
}
protected double performOperation(String operator) {
/*
* If you are using Java 7, then you can use switch in place of if statements
*
* switch (operator) {
* case CLEARMEMORY:
* calculatorMemory = 0;
* break;
* case ADDTOMEMORY:
* calculatorMemory = calculatorMemory + operand;
* break;
* etc...
* }
*/
if (operator.equals(CLEAR)) {
mOperand = 0;
mWaitingOperator = "";
mWaitingOperand = 0;
// mCalculatorMemory = 0;
} else if (operator.equals(CLEARMEMORY)) {
mCalculatorMemory = 0;
} else if (operator.equals(ADDTOMEMORY)) {
mCalculatorMemory = mCalculatorMemory + mOperand;
} else if (operator.equals(SUBTRACTFROMMEMORY)) {
mCalculatorMemory = mCalculatorMemory - mOperand;
} else if (operator.equals(RECALLMEMORY)) {
mOperand = mCalculatorMemory;
} else if (operator.equals(SQUAREROOT)) {
mOperand = Math.sqrt(mOperand);
} else if (operator.equals(SQUARED)) {
mOperand = mOperand * mOperand;
} else if (operator.equals(INVERT)) {
if (mOperand != 0) {
mOperand = 1 / mOperand;
}
} else if (operator.equals(TOGGLESIGN)) {
mOperand = -mOperand;
} else if (operator.equals(SINE)) {
mOperand = Math.sin(Math.toRadians(mOperand)); // Math.toRadians(mOperand) converts result to degrees
} else if (operator.equals(COSINE)) {
mOperand = Math.cos(Math.toRadians(mOperand)); // Math.toRadians(mOperand) converts result to degrees
} else if (operator.equals(TANGENT)) {
mOperand = Math.tan(Math.toRadians(mOperand)); // Math.toRadians(mOperand) converts result to degrees
} else {
performWaitingOperation();
mWaitingOperator = operator;
mWaitingOperand = mOperand;
}
return mOperand;
}
protected void performWaitingOperation() {
if (mWaitingOperator.equals(ADD)) {
mOperand = mWaitingOperand + mOperand;
} else if (mWaitingOperator.equals(SUBTRACT)) {
mOperand = mWaitingOperand - mOperand;
} else if (mWaitingOperator.equals(MULTIPLY)) {
mOperand = mWaitingOperand * mOperand;
} else if (mWaitingOperator.equals(DIVIDE)) {
if (mOperand != 0) {
mOperand = mWaitingOperand / mOperand;
}
}
}
}
activity_main.xml (in res/layout)
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/functionPad"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin" >
<LinearLayout
android:id="@+id/row1"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight=".12" >
<TextView
android:id="@+id/textView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="right"
android:maxLines="1"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:text="0"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textSize="40sp" />
</LinearLayout>
<LinearLayout
android:id="@+id/row2"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight=".12" >
<Button
android:id="@+id/buttonClearMemory"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/buttonClearMemory"
android:textSize="25sp" />
<Button
android:id="@+id/buttonAddToMemory"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/buttonAddToMemory"
android:textSize="25sp" />
<Button
android:id="@+id/buttonSubtractFromMemory"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/buttonSubtractFromMemory"
android:textSize="25sp" />
<Button
android:id="@+id/buttonRecallMemory"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/buttonRecallMemory"
android:textSize="25sp" />
</LinearLayout>
<LinearLayout
android:id="@+id/row3"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight=".12" >
<Button
android:id="@+id/buttonClear"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/buttonClear"
android:textSize="25sp" />
<Button
android:id="@+id/buttonToggleSign"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/buttonToggleSign"
android:textSize="25sp" />
<Button
android:id="@+id/buttonDivide"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/buttonDivide"
android:textSize="25sp" />
<Button
android:id="@+id/buttonMultiply"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/buttonMultiply"
android:textSize="25sp" />
</LinearLayout>
<LinearLayout
android:id="@+id/row4"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight=".12" >
<Button
android:id="@+id/button7"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/button7"
android:textSize="25sp" />
<Button
android:id="@+id/button8"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/button8"
android:textSize="25sp" />
<Button
android:id="@+id/button9"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/button9"
android:textSize="25sp" />
<Button
android:id="@+id/buttonSubtract"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/buttonSubtract"
android:textSize="25sp" />
</LinearLayout>
<LinearLayout
android:id="@+id/row5"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight=".12" >
<Button
android:id="@+id/button4"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/button4"
android:textSize="25sp" />
<Button
android:id="@+id/button5"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/button5"
android:textSize="25sp" />
<Button
android:id="@+id/button6"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/button6"
android:textSize="25sp" />
<Button
android:id="@+id/buttonAdd"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/buttonAdd"
android:textSize="25sp" />
</LinearLayout>
<LinearLayout
android:id="@+id/row6"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight=".24"
android:baselineAligned="false" >
<LinearLayout
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".75"
android:orientation="vertical" >
<LinearLayout
android:id="@+id/linearLayout1"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight=".50"
android:textSize="25sp" >
<Button
android:id="@+id/button1"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".33"
android:text="@string/button1"
android:textSize="25sp" />
<Button
android:id="@+id/button2"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".33"
android:text="@string/button2"
android:textSize="25sp" />
<Button
android:id="@+id/button3"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".34"
android:text="@string/button3"
android:textSize="25sp" />
</LinearLayout>
<LinearLayout
android:id="@+id/linearLayout2"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight=".50" >
<Button
android:id="@+id/button0"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".66"
android:text="@string/button0"
android:textSize="25sp" />
<Button
android:id="@+id/buttonDecimalPoint"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".34"
android:text="@string/buttonDecimalPoint"
android:textSize="25sp" />
</LinearLayout>
</LinearLayout>
<Button
android:id="@+id/buttonEquals"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".25"
android:text="@string/buttonEquals"
android:textSize="25sp" />
</LinearLayout>
</LinearLayout>
activity_main.xml (in res/layout-land)
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/functionPad"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin" >
<LinearLayout
android:id="@+id/row1"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight=".16" >
<TextView
android:id="@+id/textView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="right"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:text="0"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textSize="30sp" />
</LinearLayout>
<LinearLayout
android:id="@+id/row2"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight=".16" >
<Button
android:id="@+id/buttonClearMemory"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonClearMemory" />
<Button
android:id="@+id/buttonSquareRoot"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonSquareRoot" />
<Button
android:id="@+id/button7"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/button7" />
<Button
android:id="@+id/button8"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/button8" />
<Button
android:id="@+id/button9"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/button9" />
<Button
android:id="@+id/buttonToggleSign"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonToggleSign" />
<Button
android:id="@+id/buttonClear"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonClear" />
</LinearLayout>
<LinearLayout
android:id="@+id/row3"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight=".16" >
<Button
android:id="@+id/buttonRecallMemory"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonRecallMemory" />
<Button
android:id="@+id/buttonSquared"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonSquared" />
<Button
android:id="@+id/button4"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/button4" />
<Button
android:id="@+id/button5"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/button5" />
<Button
android:id="@+id/button6"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/button6" />
<Button
android:id="@+id/buttonMultiply"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonMultiply" />
<Button
android:id="@+id/buttonDivide"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonDivide" />
</LinearLayout>
<LinearLayout
android:id="@+id/row4"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight=".16" >
<Button
android:id="@+id/buttonAddToMemory"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonAddToMemory" />
<Button
android:id="@+id/buttonInvert"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonInvert" />
<Button
android:id="@+id/button1"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/button1" />
<Button
android:id="@+id/button2"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/button2" />
<Button
android:id="@+id/button3"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/button3" />
<Button
android:id="@+id/buttonAdd"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonAdd" />
<Button
android:id="@+id/buttonSubtract"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonSubtract" />
</LinearLayout>
<LinearLayout
android:id="@+id/row5"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight=".16" >
<Button
android:id="@+id/buttonSubtractFromMemory"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonSubtractFromMemory" />
<Button
android:id="@+id/buttonSine"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonSine" />
<Button
android:id="@+id/buttonCosine"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonCosine" />
<Button
android:id="@+id/buttonTangent"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonTangent" />
<Button
android:id="@+id/button0"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/button0" />
<Button
android:id="@+id/buttonDecimalPoint"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonDecimalPoint" />
<Button
android:id="@+id/buttonEquals"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight=".142"
android:text="@string/buttonEquals" />
</LinearLayout>
</LinearLayout>
strings.xml (in res/values)
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">Calculator</string>
<string name="menu_settings">Settings</string>
<string name="action_settings">Settings</string>
<string name="button0">0</string>
<string name="button1">1</string>
<string name="button2">2</string>
<string name="button3">3</string>
<string name="button4">4</string>
<string name="button5">5</string>
<string name="button6">6</string>
<string name="button7">7</string>
<string name="button8">8</string>
<string name="button9">9</string>
<string name="buttonAdd">+</string>
<string name="buttonSubtract">-</string>
<string name="buttonMultiply">*</string>
<string name="buttonDivide">/</string>
<string name="buttonToggleSign">+/-</string>
<string name="buttonDecimalPoint">.</string>
<string name="buttonEquals">=</string>
<string name="buttonClear">C</string>
<string name="buttonClearMemory">MC</string>
<string name="buttonAddToMemory">M+</string>
<string name="buttonSubtractFromMemory">M-</string>
<string name="buttonRecallMemory">MR</string>
<string name="buttonSquareRoot">√</string>
<string name="buttonSquared">x²</string>
<string name="buttonInvert">1/x</string>
<string name="buttonSine">sin</string>
<string name="buttonCosine">cos</string>
<string name="buttonTangent">tan</string>
</resources>
Screenshot of the application
Category: Android Application Development
Just wanted to say that this was a great tutorial. It had some code errors when I tried to compile it with the newer libraries, but still works well, and is a great basis for starting a more complex calculator. Thanks for sharing.
thanks a lot ….it worked is executing and showing no error
but
calculator is
NOT FUNCTIONING
It works for me. Have you updated to the latest API (17) in the SDK manager?
can u tell us how to remove leading 0
I only have a leading 0 when the value is 0. Then it shows 0.0 I don’t know how to change it. Maybe someone else will comment on this. It seems similar to how other calculators work.
this will remove 0.0 thanks to vikram from stackflow
if (new Double(brain.getResult()).equals(0.0)){calculatorDisplay.setText("" + 0);
} else {
calculatorDisplay.setText(df.format(brain.getResult()));
}
I think this is an excellent tutorial, good code and well commented so I can understand what’s going on. I only have one small issue with the portrait layout file which I only discovered after adding some custom styles to the buttons and that is that rows 5 and 6 are slightly misaligned with the rest of the layout i.e. buttons 0, 1, 2, 3, the decimal point and the = button.
Not a big deal I know but after spotting it in the styled version of the layout, I reverted to the original code and the misalignment is still there, although more difficult to spot.
I’m guessing that this is to do with the fact that row 6 spans 2 rows to accommodate the double sized 0 and = buttons but I’m unable to resolve this (yet).
Nonetheless, a very good tutorial, my thanks.
thanks a lot
thanks a lot
The code has been place on GitHub. Download at https://github.com/langhimebaugh/Calculator
thanks you sir I find this project very helpful. However I have this error. Somehow the java code that contains the codes when square root is clicked shows an error. I had to comment them to run the app. Either way it is still very helpful. Thank you sir.
Excellent article!
It is indeed working so kudos to you sir! However, I see there is a problem if you get a giant number as a result. It won’t fit in textview in its entirety so the solution would be to convert big number results into decimal numbers with exponent. Do you know how to do that?
It’s an excellent project, it helped me a lot in my studies, especially in layout. In this calculator project, is it possible to create the percentage function?
Great Calculator..was a great help