MainActivity.kt
package com.cfsuman.kotlintutorials
import android.app.Activity
import android.os.Bundle
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)
// Get an instance of base adapter
val adapter = ColorBaseAdapter()
// Set the list view adapter
listView.adapter = adapter
}
}
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"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/rootLayout"
android:background="#DCDCDC"
android:padding="12dp">
<ListView
android:id="@+id/listView"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginBottom="16dp"
android:divider="@null"
android:dividerHeight="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
ColorBaseAdapter.kt
package com.cfsuman.kotlintutorials
import android.app.Activity
import android.graphics.Bitmap
import android.graphics.Canvas
import android.graphics.Color
import android.graphics.Paint
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.BaseAdapter
import android.widget.ImageView
import android.widget.TextView
import android.widget.Toast
import androidx.cardview.widget.CardView
class ColorBaseAdapter : BaseAdapter(){
private val list = colors()
override fun getView(position:Int, convertView: View?,
parent: ViewGroup?):View{
val viewHolder:ViewHolder
var convertView = convertView
if(convertView==null){
// If convert view is null then inflate a
// custom view and use it as convert view
convertView = LayoutInflater.from(parent?.context).
inflate(R.layout.custom_view,parent,false)
// Create a new view holder instance using convert view
viewHolder = ViewHolder(convertView)
// Set the view holder as convert view tag
convertView.tag = viewHolder
}else{
/*
If convert view is not null then
initialize the view holder using convert view tag.
*/
viewHolder = convertView.tag as ViewHolder
}
// Display the current color name and value on view holder
viewHolder.colorName.text = list[position].first
viewHolder.imageView.setImageBitmap(
drawCircle(list[position].second))
// Set a click listener for card view
viewHolder.card.setOnClickListener {
// Show selected color in a toast message
Toast.makeText(parent?.context,
"Clicked : ${list[position].first}",
Toast.LENGTH_SHORT).show()
// Get the activity reference from parent
val activity = parent?.context as Activity
// Get the activity root view
val viewGroup = activity.findViewById<ViewGroup>(
android.R.id.content).getChildAt(0)
// Change the root layout background color
viewGroup.setBackgroundColor(list[position].second)
}
// Finally, return the convert view
return convertView!!
}
override fun getItem(position: Int): Any? {
return list[position]
}
override fun getItemId(position: Int): Long {
return position.toLong()
}
override fun getCount(): Int {
return list.size
}
// Custom method to generate list of color name value pair
private fun colors():List<Pair<String,Int>>{
return listOf(
Pair("INDIANRED", Color.parseColor("#CD5C5C")),
Pair("LIGHTCORAL",Color.parseColor("#F08080")),
Pair("SALMON",Color.parseColor("#FA8072")),
Pair("DARKSALMON",Color.parseColor("#E9967A")),
Pair("LIGHTSALMON",Color.parseColor("#FFA07A")),
Pair("CRIMSON",Color.parseColor("#DC143C")),
Pair("RED",Color.parseColor("#FF0000")),
Pair("FIREBRICK",Color.parseColor("#B22222")),
Pair("DARKRED",Color.parseColor("#8B0000")),
Pair("PINK",Color.parseColor("#FFC0CB")),
Pair("LIGHTPINK",Color.parseColor("#FFB6C1")),
Pair("HOTPINK",Color.parseColor("#FF69B4")),
Pair("DEEPPINK",Color.parseColor("#FF1493")),
Pair("MEDIUMVIOLETRED",Color.parseColor("#C71585")),
Pair("PALEVIOLETRED",Color.parseColor("#DB7093")),
Pair("LIGHTSALMON",Color.parseColor("#FFA07A")),
Pair("CORAL",Color.parseColor("#FF7F50")),
Pair("TOMATO",Color.parseColor("#FF6347")),
Pair("ORANGERED",Color.parseColor("#FF4500")),
Pair("DARKORANGE",Color.parseColor("#FF8C00")),
Pair("ORANGE",Color.parseColor("#FFA500")),
Pair("GOLD",Color.parseColor("#FFD700")),
Pair("YELLOW",Color.parseColor("#FFFF00")),
Pair("LIGHTYELLOW",Color.parseColor("#FFFFE0")),
Pair("LEMONCHIFFON",Color.parseColor("#FFFACD")),
Pair("LIGHTGOLDENRODYELLOW",Color.parseColor("#FAFAD2")),
Pair("PAPAYAWHIP",Color.parseColor("#FFEFD5")),
Pair("MOCCASIN",Color.parseColor("#FFE4B5")),
Pair("PEACHPUFF",Color.parseColor("#FFDAB9")),
Pair("PALEGOLDENROD",Color.parseColor("#EEE8AA")),
Pair("KHAKI",Color.parseColor("#F0E68C")),
Pair("DARKKHAKI",Color.parseColor("#BDB76B"))
)
}
private fun drawCircle(color:Int=Color.WHITE,width:Int=200): Bitmap {
// Initialize a new Bitmap object
val bitmap:Bitmap = Bitmap.createBitmap(
width, // Width
width, // Height
Bitmap.Config.ARGB_8888 // Config
)
// Initialize a new Canvas instance
val canvas: Canvas = Canvas(bitmap)
// Draw a solid color to the canvas background
canvas.drawColor(Color.TRANSPARENT)
// Initialize a new Paint instance to draw the Circle
val paint: Paint = Paint()
paint.style =Paint.Style.FILL
paint.color = color
paint.isAntiAlias = true
// Calculate the available radius of canvas
val radius:Int = Math.min(canvas.width,canvas.height/2)
// Set a pixels value to padding around the circle
val padding:Int = 5
// Finally, draw the circle on the canvas
canvas.drawCircle(
(canvas.width / 2).toFloat(), // cx
(canvas.height / 2).toFloat(), // cy
(radius - padding).toFloat(), // Radius
paint // Paint
)
// Return the newly created bitmap
return bitmap
}
}
private class ViewHolder(view:View){
var colorName: TextView = view.findViewById(R.id.colorName)
var imageView: ImageView = view.findViewById(R.id.imageView)
val card: CardView = view.findViewById(R.id.cardView)
}
custom_view.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="wrap_content">
<androidx.cardview.widget.CardView
android:id="@+id/cardView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="4dp"
app:cardBackgroundColor="#F8F8F8"
app:cardCornerRadius="8dp"
app:cardElevation="4dp"
app:cardMaxElevation="6dp"
app:contentPadding="16dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/colorName"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:fontFamily="sans-serif"
android:gravity="center"
android:textSize="20sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/imageView"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
</androidx.constraintlayout.widget.ConstraintLayout>
- kotlin - List and ArrayList example
- kotlin - RecyclerView example
- kotlin - Extension function example
- kotlin - NumberPicker example
- kotlin - Navigation drawer example
- kotlin - GridView with BaseAdapter example
- kotlin - Room database example
- kotlin - Google maps example
- kotlin - TextInputLayout and TextInputEditText example
- kotlin - Material button example