MainActivity.kt
package com.example.jetpack
import android.app.Activity
import android.content.Context
import android.os.Build
import android.os.Bundle
import android.util.DisplayMetrics
import android.util.TypedValue
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.activity_main.*
import kotlin.math.roundToInt
import kotlin.random.Random
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// generate random integer and float value
val random = Random.nextInt(50,100)
val randomFloat = Random.nextFloat() * 100
// show the screen density
textView.text = "Screen Density: ${displayMetrics.density}"
// convert integer dp value to equivalent pixels value
textView.append("\n\nRandom Number : $random")
val pixels = random.dpToPixels(this)
textView.append("\n$random dp = $pixels pixels (Float)")
textView.append("\n$random dp = ${pixels.roundToInt()} pixels (Int)")
// convert integer pixels value to equivalent dp value
val dp = random.pixelsToDp(this)
textView.append("\n\n$random pixels = $dp dp (Float)")
textView.append("\n$random pixels = ${dp.roundToInt()} dp (Int)")
// convert float pixels and dp to equivalent dp and pixels value
textView.append("\n\nRandom Float : $randomFloat")
textView.append("\n$randomFloat dp =" +
" ${randomFloat.dpToPixels(this)} pixels")
textView.append("\n$randomFloat pixels =" +
" ${randomFloat.pixelsToDp(this)} dp")
}
}
// extension function to convert dp to equivalent pixels
fun Int.dpToPixels(context: Context):Float = TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP,this.toFloat(),context.resources.displayMetrics
)
// input float dp value to convert equivalent pixels
fun Float.dpToPixels(context: Context):Float = TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP,this,context.resources.displayMetrics
)
// extension function to convert pixels to equivalent dp
fun Int.pixelsToDp(context: Context):Float{
return this / (context.resources
.displayMetrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT).toFloat()
}
// input float pixels value to convert equivalent dp
fun Float.pixelsToDp(context: Context):Float{
return this / (context.resources
.displayMetrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT).toFloat()
}
// extension property to get display metrics instance
val Activity.displayMetrics: DisplayMetrics
get() {
val displayMetrics = DisplayMetrics()
if (Build.VERSION.SDK_INT >= 30){
display?.apply {
getRealMetrics(displayMetrics)
}
}else{
// getMetrics() method was deprecated in api level 30
windowManager.defaultDisplay.getMetrics(displayMetrics)
}
return displayMetrics
}
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:id="@+id/constraintLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#E5E4E2"
tools:context=".MainActivity">
<TextView
android:id="@+id/textView"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="32dp"
android:layout_marginEnd="16dp"
android:fontFamily="sans-serif-condensed"
android:textColor="#191970"
android:textSize="25sp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:text="TextView" />
</androidx.constraintlayout.widget.ConstraintLayout>