How to Convert Pixel to DP in Android using Jetpack Compose?

We have seen the usage of many units while building android applications. These units are given different views such as image view, and text view to specify their height and width within the android application. Many times we also want to convert one unit to another unit. In this article, we will take a look at How to convert Pixel to DP in Android applications using Jetpack Compose. 

Step By Step Implementation

Step 1: Create a New Project in Android Studio

To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio. While choosing the template, select Empty Compose Activity. If you do not find this template, try upgrading the Android Studio to the latest version. We demonstrated the application in Kotlin, so make sure you select Kotlin as the primary language while creating a New Project.

Step 2: Adding a new color to the Color.kt file

Navigate to app > java > your app’s package name > ui.theme > Color.kt file and add the below code to it. 

Kotlin

import androidx.compose.ui.graphics.Color

val Purple200 = Color(0xFF0F9D58)
val Purple500 = Color(0xFF0F9D58)
val Purple700 = Color(0xFF3700B3)
val Teal200 = Color(0xFF03DAC5)

// on below line we are adding different colors.
val greenColor = Color(0xFF0F9D58)

Step 3: Working with MainActivity.kt file. 

Navigate to app>java>your app’s package name>MainActivity.kt file and add the below code to it. Comments are added in the code to get to know in detail. 

Kotlin

import android.app.Activity
import android.content.Context
import android.os.Build
import android.os.Bundle
import android.widget.Toast
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.annotation.RequiresApi
import androidx.compose.foundation.layout.*
import androidx.compose.material.*
import androidx.compose.runtime.Composable
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.platform.LocalContext
import androidx.compose.ui.text.TextStyle
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.input.TextFieldValue
import androidx.compose.ui.text.style.TextAlign
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import com.example.newcanaryproject.ui.theme.NewCanaryProjectTheme
import com.example.newcanaryproject.ui.theme.greenColor

class MainActivity : ComponentActivity() {
    @RequiresApi(Build.VERSION_CODES.M)
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            NewCanaryProjectTheme {
                // on below line we are specifying background color for our application
                Surface(
                    // on below line we are specifying modifier and color for our app
                    modifier = Modifier.fillMaxSize(), color = MaterialTheme.colors.background
                ) {
                    // on the below line we are specifying the theme as the scaffold.
                    Scaffold(
                        // in scaffold we are specifying the top bar.
                        topBar = {
                            // inside top bar we are specifying background color.
                            TopAppBar(backgroundColor = greenColor,
                                // along with that we are specifying title for our top bar.
                                title = {
                                    // in the top bar we are specifying tile as a text
                                    Text(
                                        // on below line we are specifying
                                        // text to display in top app bar.
                                        text = "GFG",

                                        // on below line we are specifying
                                        // modifier to fill max width.
                                        modifier = Modifier.fillMaxWidth(),

                                        // on below line we are specifying
                                        // text alignment.
                                        textAlign = TextAlign.Center,

                                        // on below line we are specifying
                                        // color for our text.
                                        color = Color.White
                                    )
                                })
                        }) {
                        // on below line we are calling connection information method to display UI
                        convertPixelToDp(LocalContext.current)
                    }
                }
            }
        }
    }
}

// on below line we are creating contact picker function.
@Composable
fun convertPixelToDp(
    context: Context
) {
    // in the below line, we are creating
    // variables for pixel and dp value
    val pixelValue = remember {
        mutableStateOf(TextFieldValue())
    }
    val dpValue = remember {
        mutableStateOf("")
    }

    // on below line we are creating a column,
    Column(
        // on below line we are adding a modifier to it,
        modifier = Modifier
            .fillMaxSize()
            // on below line we are adding a padding.
            .padding(all = 30.dp),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.Center,
    ) {
        // on below line we are adding a text for heading.
        Text(
            // on below line we are specifying text
            text = "Pixel to DP Converter",
            // on below line we are specifying text color, font size and font weight
            color = greenColor, fontSize = 20.sp, fontWeight = FontWeight.Bold
        )

        // in the below line, we are creating a text field
        // for getting URL from user.
        TextField(
            // on below line we are specifying
            // value for our  text field.
            value = pixelValue.value,

            // on below line we are adding on
            // value change for text field.
            onValueChange = { pixelValue.value = it },

            // on below line we are adding place holder as text
            placeholder = { Text(text = "Enter pixel value") },

            // on below line we are adding modifier to it
            // and adding padding to it and filling max width
            modifier = Modifier
                .padding(16.dp)
                .fillMaxWidth(),
            // on below line we are adding text style
            // specifying color and font size to it.
            textStyle = TextStyle(color = Color.Black, fontSize = 15.sp),

            // on below line we are
            // adding single line to it.
            singleLine = true,
        )

        // on below line adding a spacer.
        Spacer(modifier = Modifier.height(20.dp))

        // on below line creating a button to convert pixel to dp.
        Button(onClick = {
            if (pixelValue.value.text.toString().isNotEmpty()) {
                val screenPixelDensity = context.resources.displayMetrics.density
                val dpVal = pixelValue.value.text.toFloat() / screenPixelDensity
                dpValue.value = "DP Value is : " + dpVal
            } else {
                Toast.makeText(context, "Please enter valid value..", Toast.LENGTH_SHORT).show()
            }
        }) {
            // on below line creating a text for our button.
            Text(
                // on below line adding a text ,
                // padding, color and font size.
                text = "Convert Pixel to DP",
                modifier = Modifier.padding(10.dp),
                color = Color.White,
                fontSize = 15.sp
            )
        }
        // on below line adding a spacer.
        Spacer(modifier = Modifier.height(20.dp))

        // on below line creating a text view for displaying dp value.
        Text(
            text = dpValue.value, color = greenColor, fontSize = 20.sp, fontWeight = FontWeight.Bold
        )
    }
}

Output: