Calculator

MainActivity

package com.example.calculator

import android.annotation.SuppressLint
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.*

class MainActivity : AppCompatActivity() {

private lateinit var addBtn : RadioButton
private lateinit var subBtn : RadioButton
private lateinit var mulBtn : RadioButton
private lateinit var divBtn : RadioButton

private lateinit var number1 : EditText

private lateinit var number2 : EditText

private lateinit var displayBtn : Button

private lateinit var clearBtn : Button
private lateinit var displayView : TextView

@SuppressLint("MissingInflatedId")
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)

addBtn = findViewById(R.id.add)
subBtn = findViewById(R.id.sub)
mulBtn = findViewById(R.id.mul)
divBtn = findViewById(R.id.div)
number1 = findViewById(R.id.num1)
number2 = findViewById(R.id.num2)
displayBtn = findViewById(R.id.display)
 clearBtn = findViewById(R.id.clear)
displayView = findViewById(R.id.res)

var result : Int = 0

var a=number1.text.toString().toInt()
var b=number2.text.toString().toInt()
addBtn.setOnClickListener {
result = a+b
}

subBtn.setOnClickListener {
result = a-b
}

mulBtn.setOnClickListener {
result = a*b
}

divBtn.setOnClickListener {
result = a/b
}

displayBtn.setOnClickListener {
displayView.text = result.toString()
}

clearBtn.setOnClickListener {
number1.setText("")
number2.setText("")
displayView.text = ""
}
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">

<TextView
android:id="@+id/calculator_heading"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Calculator"
android:textSize="24sp"
android:textStyle="bold"
android:layout_centerHorizontal="true"
android:layout_marginTop="32dp" />

<EditText
android:id="@+id/num1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/calculator_heading"
android:layout_centerHorizontal="true"
android:layout_marginTop="32dp"
android:hint="Enter number 1"
android:inputType="number" />

<EditText
android:id="@+id/num2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/num1"
android:layout_centerHorizontal="true"
android:layout_marginTop="16dp"
android:hint="Enter number 2"
android:inputType="number" />

<RadioGroup
android:id="@+id/radioGroup"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
 android:layout_below="@id/num2"
android:layout_centerHorizontal="true"
android:layout_marginTop="16dp">

<RadioButton
android:id="@+id/add"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Add" />

<RadioButton
android:id="@+id/sub"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Subtract" />

<RadioButton
android:id="@+id/mul"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Multiply" />

<RadioButton
android:id="@+id/div"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Divide" />
</RadioGroup>

<Button
android:id="@+id/display"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/radioGroup"
android:layout_centerHorizontal="true"
android:layout_marginTop="16dp"
android:text="Calculate" />

<Button
android:id="@+id/clear"
 android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/display"
android:layout_centerHorizontal="true"
android:layout_marginTop="16dp"
android:text="Clear" />

<TextView
android:id="@+id/res"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/clear"
android:layout_centerHorizontal="true"
android:layout_marginTop="16dp"
android:textSize="24sp" />

</RelativeLayout>

Image Selection

MainActivity

package com.example.fruits

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.*

class MainActivity : AppCompatActivity() {

private lateinit var displayBtn : Button
private lateinit var nameET : EditText
private lateinit var colorET : EditText
private lateinit var image : ImageView

override fun onCreate(savedInstanceState: Bundle?) {

super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)

image = findViewById(R.id.image)
nameET = findViewById(R.id.name)
 colorET = findViewById(R.id.color)
displayBtn = findViewById(R.id.display)

displayBtn.setOnClickListener {
val fName = nameET.text.toString()
val fColor = colorET.text.toString()

if(fName == "apple" && fColor == "red")

image.setImageResource(R.drawable.apple)
if(fName == "banana" && fColor == "yellow")
image.setImageResource(R.drawable.banana)
if(fName == "orange" && fColor == "orange")
image.setImageResource(R.drawable.orange)
}
}
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

<androidx.constraintlayout.widget.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">

<TextView
android:id="@+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="FRUITS"
android:textSize="24dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.066" />

<EditText
 android:id="@+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="textPersonName"
android:hint="Name"
app:layout_constraintBottom_toTopOf="@+id/color"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/text" />

<EditText
android:id="@+id/color"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="76dp"
android:ems="10"
android:hint="Color"
android:inputType="textPersonName"
app:layout_constraintBottom_toTopOf="@+id/image"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.502"
app:layout_constraintStart_toStartOf="parent" />

<Button
android:id="@+id/display"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="44dp"
android:text="Button"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent" />

<ImageView
android:id="@+id/image"
android:layout_width="360dp"
android:layout_height="245dp"
android:layout_marginBottom="32dp"
 app:layout_constraintBottom_toTopOf="@+id/display"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.49"
app:layout_constraintStart_toStartOf="parent"
app:srcCompat="@drawable/apple" />

</androidx.constraintlayout.widget.ConstraintLayout>

Score Board

MainActivity

package com.example.courtcounter

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.TextView

class MainActivity : AppCompatActivity() {

private var scoreTeamA = 0
private var scoreTeamB = 0

override fun onCreate(savedInstanceState: Bundle?) {

super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
}

fun addThreeForTeamA(view: View) {

scoreTeamA += 3
displayForTeamA(scoreTeamA)
}

fun addTwoForTeamA(view: View) {

scoreTeamA += 2
displayForTeamA(scoreTeamA)
}

fun addOneForTeamA(view: View) {

scoreTeamA += 1
displayForTeamA(scoreTeamA)
 }

fun addThreeForTeamB(view: View) {

scoreTeamB += 3
displayForTeamB(scoreTeamB)
}

fun addTwoForTeamB(view: View) {

scoreTeamB += 2
displayForTeamB(scoreTeamB)
}

fun addOneForTeamB(view: View) {

scoreTeamB += 1
displayForTeamB(scoreTeamB)
}

fun resetScores(view: View) {

scoreTeamA = 0
scoreTeamB = 0
displayForTeamA(scoreTeamA)
displayForTeamB(scoreTeamB)
}

private fun displayForTeamA(score: Int) {

val scoreView = findViewById<TextView>(R.id.score_team_a)
scoreView.text = "$score"
}

private fun displayForTeamB(score: Int) {

val scoreView = findViewById<TextView>(R.id.score_team_b)
scoreView.text = "$score"
}
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout 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:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="500dp"
android:padding="16dp"
tools:context=".MainActivity">

<LinearLayout
android:layout_width="match_parent"
android:layout_height="416dp"
android:layout_weight="1"
android:orientation="horizontal"
android:weightSum="2">

<LinearLayout
android:layout_width="0dp"
android:layout_height="416dp"
android:layout_weight="1"
android:gravity="center"
android:orientation="vertical"
android:padding="8dp">

<TextView
android:id="@+id/team_a_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Team A"
android:textSize="18sp" />

<TextView
android:id="@+id/score_team_a"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="0"
android:textSize="36sp" />

<Button
android:id="@+id/button_team_a_3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
 android:onClick="addThreeForTeamA"
android:text="+3 Points" />

<Button
android:id="@+id/button_team_a_2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="addTwoForTeamA"
android:text="+2 Points" />

<Button
android:id="@+id/button_team_a_free_throw"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="addOneForTeamA"
android:text="Free Throw" />
</LinearLayout>

<View
android:layout_width="1dp"
android:layout_height="416dp"
android:background="@android:color/darker_gray" />

<LinearLayout
android:layout_width="0dp"
android:layout_height="416dp"
android:layout_weight="1"
android:gravity="center"
android:orientation="vertical"
android:padding="8dp">

<TextView
android:id="@+id/team_b_name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Team B"
android:textSize="18sp" />

<TextView
android:id="@+id/score_team_b"
 android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="0"
android:textSize="36sp" />

<Button
android:id="@+id/button_team_b_3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="addThreeForTeamB"
android:text="+3 Points" />

<Button
android:id="@+id/button_team_b_2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="addTwoForTeamB"
android:text="+2 Points" />

<Button
android:id="@+id/button_team_b_free_throw"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="addOneForTeamB"
android:text="Free Throw" />
</LinearLayout>
</LinearLayout>

<Button
android:id="@+id/button_reset"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Reset"
android:layout_gravity="center_horizontal"
android:onClick="resetScores"/>
</LinearLayout>

Login application

MainActivity
package com.example.loginapplication

import android.content.Intent
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button
import android.widget.EditText
import android.widget.Toast

class MainActivity : AppCompatActivity() {

private lateinit var userIT : EditText
private lateinit var passIT : EditText
private lateinit var resetBtn : Button
private lateinit var loginBtn : Button

override fun onCreate(savedInstanceState: Bundle?) {

super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)

userIT = findViewById(R.id.username)
passIT = findViewById(R.id.password)
resetBtn = findViewById(R.id.resetBtn)
loginBtn = findViewById(R.id.loginBtn)

resetBtn.setOnClickListener() {
userIT.setText(" ")
passIT.setText(" ")
}

loginBtn.setOnClickListener() {
val user = userIT.text.toString()
val pass = passIT.text.toString()

if(user.equals("CVR") && pass.equals("1234"))

{
val intent = Intent(this , HomeActivity1 :: class.java)
intent.putExtra("Username" , user)
intent.putExtra("Password" , pass )
startActivity(intent)
Toast.makeText(this , "Login is Successful" , Toast.LENGTH_LONG).show()
 }
else
{
Toast.makeText(this , "Login is not Successful" , Toast.LENGTH_LONG).show()
}
}
}
}

HomeActivity1.kt

package com.example.loginapplication

import android.content.Intent
import android.os.Bundle
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity

class HomeActivity1 : AppCompatActivity(){

private lateinit var resultV : TextView
override fun onCreate(savedInstanceState : Bundle?){
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_home1)

resultV = findViewById(R.id.resTV)
val intent : Intent = intent
val user = intent.getStringExtra("Username")
val pass = intent.getStringExtra("Password")
resultV.setText(user + " " + pass)
}
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>

<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="@+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Login Application"
android:textAlignment="center"

android:textSize="24dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.057" />

<EditText
android:id="@+id/username"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="24dp"
android:ems="10"
android:hint="Enter Username"
android:inputType="textPersonName"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.497"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView4" />

<EditText
android:id="@+id/password"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="36dp"
android:ems="10"
android:hint="Enter Password"
android:inputType="numberPassword"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.497"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/username" />
 <Button
android:id="@+id/resetBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="112dp"
android:layout_marginTop="68dp"
android:text="RESET"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/password" />

<Button
android:id="@+id/loginBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="68dp"
android:layout_marginEnd="112dp"
android:text="LOGIN"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="@+id/password" />

</androidx.constraintlayout.widget.ConstraintLayout>

activity_home1.xml

<?xml version="1.0" encoding="utf-8"?>

<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">

<TextView
android:id="@+id/resTV"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Welcome!!"
android:textAlignment="center"
android:textSize="24dp"
 app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.057" />

</androidx.constraintlayout.widget.ConstraintLayout>

AndroidMainfest.xml

</activity>
<activity android:name=".HomeActivity1"/>