Convert Pixels to DP in an Android App Using Kotlin

This example demonstrates how to convert pixels to dp in an Android App using Kotlin.

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.xml.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   tools:context=".MainActivity">
   <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerHorizontal="true"
      android:layout_marginTop="50dp"
      android:text="Tutorials Point"
      android:textAlignment="center"
      android:textColor="@android:color/holo_green_dark"
      android:textSize="32sp"
      android:textStyle="bold" />
   <Button
      android:id="@+id/button"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_centerInParent="true"
      android:text="Convert Pixels to DPs" />
   <TextView
      android:id="@+id/textView"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_below="@id/button"
      android:textAlignment="center"
      android:textColor="#ff0000"
      android:textSize="24sp"
      android:textStyle="bold" />
</RelativeLayout>

Step 3 − Add the following code to src/MainActivity.kt

import android.content.Context
import android.os.Bundle
import android.widget.Button
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import kotlin.math.roundToInt
class MainActivity : AppCompatActivity() {
   override fun onCreate(savedInstanceState: Bundle?) {
      super.onCreate(savedInstanceState)
      setContentView(R.layout.activity_main)
      title = "KotlinApp"
      val button = findViewById<Button>(R.id.button)
      val textView = findViewById<TextView>(R.id.textView)
      button.setOnClickListener {
         val pixelsOne = 38
         val pixelsTwo = 43
         val context: Context = applicationContext
         textView.text = """
         Convert Pixels to integer DPs value:
         ${pixelsOne}pixels = ${getDPsFromPixels(context, pixelsOne)}dp
         ${pixelsTwo}pixels = ${getDPsFromPixels(context, pixelsTwo)}
         """.trimIndent()
         textView.text = (textView.text.toString() + "Convert Pixels to perfect DPs value: 
"
         + pixelsOne + "pixels = " + getActualDPsFromPixels(context, pixelsOne)
         + "dp
" + pixelsOne + "pixels = " + getActualDPsFromPixels(context, pixelsOne))
      }
   }
   private fun getDPsFromPixels(context: Context, pixels: Int): Int {
      val resources = context.resources
      return (pixels / (resources.displayMetrics.densityDpi / 160f)).roundToInt()
   }
   private fun getActualDPsFromPixels(context: Context, pixels: Int): Float {
      val resources = context.resources
      return pixels / (resources.displayMetrics.densityDpi / 160f)
   }
}

Step 4 − Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.q11">
   <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:supportsRtl="true"
      android:theme="@style/AppTheme">
      <activity android:name=".MainActivity">
         <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
   </application>
</manifest>

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click the Run icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen