Question

You recently started working in at a University in the Math department as a software programmer. You need to build an app that can calculate the mod of two numbers. Users need to enter num1 and num2. The app should perform the calculation and display the output as num1 mod nub2 operation.

For example, 25 mod 5=0

24 mod 5 = 4

Once you implement the mod operations, then you need to add following buttons.

• Addition
• Subtraction
• Division
• Power

Follow these steps to complete the lab.

1. Create the android studio project
2. Use Android studio layout editor
3. Add textboxes and labels according to the UI
4. Add Button in the UI
5. Review the XML code of the design
6. Declare the variable before the oncreate function
7. Read the value from textboxes and assign it to the variable
8. Add the click event for the button
9. Display the output
10. Declare the variable before the oncreate function

Answer 1

I am adding the XML and java code files below:

Say your project name in Android Studio that you've created be "MyApplication" and package name given be "com.pac":

activity_main.xml

<?xml version="1.0" encoding="utf-8"?> <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity"> <EditText android:id="@+id/etNum1" android:layout_width="152dp" android:layout_height="78dp" android:layout_marginStart="8dp" android:layout_marginTop="8dp" android:layout_marginEnd="8dp" android:layout_marginBottom="8dp" android:ems="10" android:hint="number 1" android:inputType="textPersonName" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.106" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.062" /> <EditText android:id="@+id/etResult" android:layout_width="152dp" android:layout_height="78dp" android:layout_marginStart="8dp" android:layout_marginTop="8dp" android:layout_marginEnd="8dp" android:layout_marginBottom="8dp" android:ems="10" android:hint="Result" android:inputType="textPersonName" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.875" /> <Button android:id="@+id/btnMod" android:layout_width="154dp" android:layout_height="58dp" android:layout_marginStart="8dp" android:layout_marginTop="8dp" android:layout_marginEnd="8dp" android:layout_marginBottom="8dp" android:text="MOD" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.531" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.302" /> <Button android:id="@+id/btnPow" android:layout_width="154dp" android:layout_height="58dp" android:layout_marginStart="8dp" android:layout_marginTop="8dp" android:layout_marginEnd="8dp" android:layout_marginBottom="8dp" android:text="POWER" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.887" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.654" /> <Button android:id="@+id/btnDiv" android:layout_width="154dp" android:layout_height="58dp" android:layout_marginStart="8dp" android:layout_marginTop="8dp" android:layout_marginEnd="8dp" android:layout_marginBottom="8dp" android:text="DIVIDE" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.099" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.654" /> <Button android:id="@+id/btnSub" android:layout_width="154dp" android:layout_height="58dp" android:layout_marginStart="8dp" android:layout_marginTop="8dp" android:layout_marginEnd="8dp" android:layout_marginBottom="8dp" android:text="SUB" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.887" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.499" /> <EditText android:id="@+id/etNum2" android:layout_width="152dp" android:layout_height="78dp" android:layout_marginStart="8dp" android:layout_marginTop="8dp" android:layout_marginEnd="8dp" android:layout_marginBottom="8dp" android:ems="10" android:hint="number 2" android:inputType="textPersonName" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.88" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.062" /> <Button android:id="@+id/btnAdd" android:layout_width="154dp" android:layout_height="58dp" android:layout_marginStart="8dp" android:layout_marginTop="8dp" android:layout_marginEnd="8dp" android:layout_marginBottom="8dp" android:text="ADD" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.107" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.499" /> <TextView android:id="@+id/textView4" android:layout_width="217dp" android:layout_height="24dp" android:layout_marginStart="8dp" android:layout_marginTop="8dp" android:layout_marginEnd="8dp" android:layout_marginBottom="8dp" android:text="Calculation options:" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintHorizontal_bias="0.707" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:layout_constraintVertical_bias="0.218" /> </android.support.constraint.ConstraintLayout>
MainActivity.java

package com.pac; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; public class MainActivity extends AppCompatActivity { EditText etNum1, etNum2, etResult; Button btnMod, btnAdd, btnSub, btnDiv, btnPow; int num1, num2; double result; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_chatbot); etNum1=findViewById(R.id.etNum1); etNum2=findViewById(R.id.etNum2); etResult=findViewById(R.id.etResult); btnAdd=findViewById(R.id.btnAdd); btnMod=findViewById(R.id.btnMod); btnSub=findViewById(R.id.btnSub); btnDiv=findViewById(R.id.btnDiv); btnPow=findViewById(R.id.btnPow); btnMod.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { num1=Integer.parseInt(etNum1.getText().toString()); num2=Integer.parseInt(etNum2.getText().toString()); etResult.setText(String.valueOf(num1%num2)); } }); btnAdd.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { num1=Integer.parseInt(etNum1.getText().toString()); num2=Integer.parseInt(etNum2.getText().toString()); etResult.setText(String.valueOf(num1+num2)); } }); btnPow.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { num1=Integer.parseInt(etNum1.getText().toString()); num2=Integer.parseInt(etNum2.getText().toString()); etResult.setText(String.valueOf(Math.pow(num1,num2))); } }); btnSub.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { num1=Integer.parseInt(etNum1.getText().toString()); num2=Integer.parseInt(etNum2.getText().toString()); etResult.setText(String.valueOf(num1-num2)); } }); btnDiv.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { num1=Integer.parseInt(etNum1.getText().toString()); num2=Integer.parseInt(etNum2.getText().toString()); etResult.setText(String.valueOf(num1/num2)); } }); } }