MainActivity.kt
package com.cfsuman.kotlintutorials
import android.app.Activity
import android.content.res.ColorStateList
import android.graphics.Color
import android.graphics.drawable.ColorDrawable
import android.graphics.drawable.RippleDrawable
import android.os.Bundle
import android.view.View
import android.view.ViewGroup
import android.widget.*
class MainActivity : Activity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// get the widgets reference from XML layout
val listView = findViewById<ListView>(R.id.listView)
val textView = findViewById<TextView>(R.id.textView)
// list to populate list view
val list = mutableListOf(
"Golden yellow",
"Han purple",
"Carrot orange",
"Carnation pink",
"Jungle green",
"Lavender blush",
"Lawn green"
)
// initialize an array adapter
val adapter:ArrayAdapter<String> = object: ArrayAdapter<String>(
this,
android.R.layout.simple_dropdown_item_1line,
list
){
override fun getView(position: Int, convertView: View?,
parent: ViewGroup): View {
val tv = super.getView(position,
convertView, parent) as TextView
// list view item alternate color
if (position % 2 == 0){
tv.background = getRippleDrawable()
}else{
tv.background = getRippleDrawable(
rippleColor = Color.parseColor("#E30022"),
contentColor = Color.parseColor("#FEFEFA")
)
}
return tv
}
}
// attach the array adapter with list view
listView.adapter = adapter
// list view item click listener
listView.onItemClickListener = AdapterView.OnItemClickListener {
parent, view, position, id ->
val clickedItem = parent?.getItemAtPosition(position)
.toString()
textView.text = "Clicked : $clickedItem"
}
}
}
// method to generate ripple drawable
fun getRippleDrawable(
rippleColor: Int = Color.parseColor("#007FFF"),
contentColor: Int = Color.parseColor("#F0FFFF"),
maskColor: Int = Color.RED
): RippleDrawable {
return RippleDrawable(
ColorStateList.valueOf(rippleColor),
ColorDrawable(contentColor),
ColorDrawable(maskColor)
)
}
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:id="@+id/rootLayout"
android:background="#DCDCDC"
android:padding="24dp">
<ListView
android:id="@+id/listView"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginBottom="16dp"
app:layout_constraintBottom_toTopOf="@+id/textView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:fontFamily="sans-serif"
android:textSize="24sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
tools:text="TextView" />
</androidx.constraintlayout.widget.ConstraintLayout>