Change Transparency of an Image in Android Jetpack Compose

In Android, we use ImageView to display an image in the application. We can use stock images or even import them from the local devices in the application for displaying them. When we use Jetpack Compose, we use the Image function for displaying images. Image Transparency is the opacity of the image. Mathematically, if opacity is 1, then the displayed image is the same as the original. Opacity or the alpha value ranges between 0 and 1. In this article, we will show you how you could change the Transparency of an Image in Android using Jetpack Compose. Follow the below steps once the IDE is ready.

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: Add an Image in the app > res > drawable folder

Import an image of your choice in the drawable folder. In our application, we named it “sample_image”.

Step 3: Working with the MainActivity.kt file

Go to the MainActivity.kt file and refer to the following code. Below is the code for the MainActivity.kt file. Comments are added inside the code to understand the code in more detail.

Kotlin

package com.geeksforgeeks.jcimagetransparency

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.Image
import androidx.compose.foundation.layout.*
import androidx.compose.material.*
import androidx.compose.runtime.Composable
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.res.painterResource
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            // Calling the composable function
            // to display element and its contents
            MainContent()
        }
    }
}

// Creating a composable
// function to display Top Bar
@Composable
fun MainContent(){
    Scaffold(
        topBar = {TopAppBar(
            title = {Text(
                "GFG | Change Image Transparency",
                color = Color.White)},
            backgroundColor = Color(0xff0f9d58)
        ) },
        content = { MyContent()}
    )
}

// Creating a composable function to
// create two Images and a spacer between them
// Calling this function as content in the above function
@Composable
fun MyContent(){
    Column(Modifier.fillMaxSize(), verticalArrangement = Arrangement.Center, horizontalAlignment = Alignment.CenterHorizontally) {

          // Displaying the original image
          Image(
            painter = painterResource(id = R.drawable.sample_image),
            contentDescription = null,
        )

        // Adding a space of 100dp
        Spacer(modifier = Modifier.height(100.dp))

        // Displaying the image with
        // less opacity (marked at 20%)
        Image(
            painter = painterResource(id = R.drawable.sample_image),
            contentDescription = null,
            alpha = 0.2F
        )
    }
}

// For displaying preview in
// the Android Studio IDE emulator
@Preview(showBackground = true)
@Composable
fun DefaultPreview() {
    MainContent()
}

Output:

When you run the application you will see two images. The first one is the original image with 100% opacity and the second one with 20% opacity as shown below.