MainActivity.kt
package com.cfsuman.kotlintutorials
import android.os.Bundle
import android.text.method.ScrollingMovementMethod
import android.widget.Button
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// get the widgets reference from XML layout
val textView = findViewById<TextView>(R.id.textView)
val btnList = findViewById<Button>(R.id.btnList)
val btnArrayList = findViewById<Button>(R.id.btnArrayList)
// make textview content scrollable
textView.movementMethod = ScrollingMovementMethod()
// list example
btnList.setOnClickListener {
// Initialize a new list
// Immutable list, read only
val list = listOf(1,2,3,4,5)
// Initialize a list which hold various
// data type elements
var anyList = listOf(1,1.5F,2.0,"Pink")
// Initialize an integer data type list
var intList = listOf<Int>(1,2,3,4,5)
// Initialize an string data type list
var stringList = listOf<String>(
"Rose","Pink","Red","Orange")
// Initialize an float data type list
var floatList = listOf<Float>(1.0F,2.5F,3.3F)
// Initialize an double data type list
var doubleList = listOf<Double>(1.1,1.6,2.9,3.5)
// Display list element in text view
textView.text = "Immutable List elements : "
// Loop through the list elements
for(element in list){
textView.text = textView.text.toString() +
element + ", "
}
// Initialize a new mutable list
// Read and write both allowed
var mutableList = mutableListOf<Int>(10,20,30)
// Display the mutable list element
textView.text = textView.text.toString() +
"\n\nMutable list elements : $mutableList"
// Add an element to list
mutableList.add(40)
// Display the mutable list element
textView.text = textView.text.toString() +
"\n\nMutable list elements after add " +
": $mutableList"
}
// array list example
btnArrayList.setOnClickListener {
// Initialize an integer array list
// using arrayListOf() method
val intArrayList = arrayListOf<Int>()
intArrayList.add(100)
// Initialize a string array list
// using arrayListOf() method
val stringArrayList = arrayListOf<String>()
stringArrayList.add("Yellow")
// Initialize a new integer data type array list
// Mutable list, read and write
val arrayList = ArrayList<Int>()
// Add elements to the list
arrayList.add(5)
arrayList.add(15)
arrayList.add(25)
arrayList.add(35)
// Add element to the list at the
// specified index position
arrayList.add(0,10)
// Now list elements
textView.text = "ArrayList elements : $arrayList"
// Remove list element by index
arrayList.removeAt(1)
// Remove list element by value
arrayList.remove(35)
// Now list elements
textView.text = textView.text.toString() +
"\n\nArrayList elements," +
" after remove : $arrayList"
}
}
}
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"
android:background="#F8F8F8"
android:padding="24dp">
<Button
android:id="@+id/btnList"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="List"
android:textAllCaps="false"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="@+id/btnArrayList"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:text="ArrayList"
android:textAllCaps="false"
app:layout_constraintBottom_toBottomOf="@+id/btnList"
app:layout_constraintStart_toEndOf="@+id/btnList" />
<TextView
android:id="@+id/textView"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginTop="16dp"
android:fontFamily="sans-serif"
android:textSize="24sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/btnList" />
</androidx.constraintlayout.widget.ConstraintLayout>


- kotlin - Button on click listener example
- kotlin - For loop break continue example
- kotlin - For loop range example
- kotlin - RecyclerView example
- kotlin - Create view programmatically
- kotlin - RadioGroup and RadioButton example
- kotlin - AlertDialog example
- kotlin - Google maps example
- kotlin - TextInputLayout and TextInputEditText example
- kotlin - Material button example