How to Create Custom Camera using CameraX in Android?
CameraX is used to create a custom camera in the app. CameraX is a Jetpack support library, built to help you make camera app development easier. A sample video is given below to get an idea about what we are going to do in this article. Note that we are going to implement this project using the Kotlin language.
Note The android.hardware.Camera package in Android was deprecated because it had several issues that made it difficult to use and maintain. One of the main issues was that the Camera class in this package used a non-standard API for interacting with the device's camera hardware, which made it difficult to support different camera models and configurations. Additionally, the Camera class did not provide access to all of the advanced features and controls that are available on newer camera hardware. To address these issues, the Android framework introduced the android.hardware.camera2 package, which provides a new, more standardized API for interacting with the device's camera hardware. The Camera2 API is designed to be more flexible and powerful than the old Camera API, and provides access to many advanced features and controls that were not available before. Furthermore, the Camera2 API provides a more consistent behavior across different devices and camera modules, this makes it easier for developer to write camera code that will work on different devices and configurations. This is the main reason why android.hardware.Camera package was deprecated, and developers should use the android.hardware.camera2 package instead.
Step by Step Implementation
Step 1: Create a new project
To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio. Note that select Kotlin as the programming language.
Step 2: Add dependency to the build.gradle file and click “sync now”
def camerax_version = “1.0.0-beta07”
// CameraX core library using camera2 implementation
implementation “androidx.camera:camera-camera2:$camerax_version”
// CameraX Lifecycle Library
implementation “androidx.camera:camera-lifecycle:$camerax_version”
// CameraX View class
implementation “androidx.camera:camera-view:1.0.0-alpha14”
If kotlin extension is missing, add kotlin-android-extensions as shown below and click on “Sync now”.
plugins {
id ‘com.android.application’
id ‘kotlin-android’
id ‘kotlin-android-extensions’
}
Step 3: Add Camera permission
Go to AndroidManifest.xml and add the camera permission.
<uses-feature android:name=”android.hardware.camera.any” />
<uses-permission android:name=”android.permission.CAMERA” />
Step 4: Working with the activity_main.xml file
Go to the activity_main.xml file and refer to the following code. Below is the code for the activity_main.xml file. Notice that there is a view called PreviewView with id viewFinder which we will use as Viewfinder for the camera.
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:layout_width = "match_parent" android:layout_height = "match_parent" android:background = "@color/black" tools:context = ".MainActivity" > < Button android:id = "@+id/camera_capture_button" android:layout_width = "120dp" android:layout_height = "120dp" android:layout_marginBottom = "50dp" android:background = "@drawable/capture_button" android:elevation = "2dp" android:scaleType = "fitCenter" android:text = "Capture Photo" app:layout_constraintBottom_toBottomOf = "parent" app:layout_constraintLeft_toLeftOf = "parent" app:layout_constraintRight_toRightOf = "parent" /> < ImageView android:id = "@+id/iv_capture" android:layout_width = "100dp" android:layout_height = "100dp" android:layout_marginEnd = "20dp" android:layout_marginBottom = "50dp" android:visibility = "gone" app:layout_constraintBottom_toBottomOf = "parent" app:layout_constraintRight_toRightOf = "parent" /> < androidx.camera.view.PreviewView android:id = "@+id/viewFinder" android:layout_width = "match_parent" android:layout_height = "450dp" android:layout_marginStart = "20dp" android:layout_marginTop = "20dp" android:layout_marginEnd = "20dp" app:layout_constraintLeft_toLeftOf = "parent" app:layout_constraintRight_toRightOf = "parent" app:layout_constraintTop_toTopOf = "parent" /> </ androidx.constraintlayout.widget.ConstraintLayout > |
Step 5: Create capture button drawable
Go to res > drawable and create a new file capture_button.xml. Below is the code of it.
XML
<? xml version = "1.0" encoding = "utf-8" ?> < shape xmlns:android = "http://schemas.android.com/apk/res/android" android:shape = "oval" > < solid android:color = "#0F9D58" /> < size android:width = "118dp" android:height = "118dp" /> </ shape > |
Step 6: 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
import android.Manifest import android.content.pm.PackageManager import android.net.Uri import android.os.Bundle import android.util.Log import android.view.View import android.widget.Button import android.widget.ImageView import android.widget.Toast import androidx.appcompat.app.AppCompatActivity import androidx.camera.core.CameraSelector import androidx.camera.core.ImageCapture import androidx.camera.core.ImageCaptureException import androidx.camera.core.Preview import androidx.camera.lifecycle.ProcessCameraProvider import androidx.core.app.ActivityCompat import androidx.core.content.ContextCompat import kotlinx.android.synthetic.main.activity_main.* import java.io.File import java.text.SimpleDateFormat import java.util.* import java.util.concurrent.ExecutorService import java.util.concurrent.Executors class MainActivity : AppCompatActivity() { private var imageCapture: ImageCapture? = null private lateinit var outputDirectory: File private lateinit var cameraExecutor: ExecutorService override fun onCreate(savedInstanceState: Bundle?) { super .onCreate(savedInstanceState) setContentView(R.layout.activity_main) // hide the action bar supportActionBar?.hide() // Check camera permissions if all permission granted // start camera else ask for the permission if (allPermissionsGranted()) { startCamera() } else { ActivityCompat.requestPermissions( this , REQUIRED_PERMISSIONS, REQUEST_CODE_PERMISSIONS) } // set on click listener for the button of capture photo // it calls a method which is implemented below findViewById<Button>(R.id.camera_capture_button).setOnClickListener { takePhoto() } outputDirectory = getOutputDirectory() cameraExecutor = Executors.newSingleThreadExecutor() } private fun takePhoto() { // Get a stable reference of the // modifiable image capture use case val imageCapture = imageCapture ?: return // Create time-stamped output file to hold the image val photoFile = File( outputDirectory, SimpleDateFormat(FILENAME_FORMAT, Locale.US).format(System.currentTimeMillis()) + ".jpg" ) // Create output options object which contains file + metadata val outputOptions = ImageCapture.OutputFileOptions.Builder(photoFile).build() // Set up image capture listener, // which is triggered after photo has // been taken imageCapture.takePicture( outputOptions, ContextCompat.getMainExecutor( this ), object : ImageCapture.OnImageSavedCallback { override fun onError(exc: ImageCaptureException) { Log.e(TAG, "Photo capture failed: ${exc.message}" , exc) } override fun onImageSaved(output: ImageCapture.OutputFileResults) { val savedUri = Uri.fromFile(photoFile) // set the saved uri to the image view findViewById<ImageView>(R.id.iv_capture).visibility = View.VISIBLE findViewById<ImageView>(R.id.iv_capture).setImageURI(savedUri) val msg = "Photo capture succeeded: $savedUri" Toast.makeText(baseContext, msg, Toast.LENGTH_LONG).show() Log.d(TAG, msg) } }) } private fun startCamera() { val cameraProviderFuture = ProcessCameraProvider.getInstance( this ) cameraProviderFuture.addListener(Runnable { // Used to bind the lifecycle of cameras to the lifecycle owner val cameraProvider: ProcessCameraProvider = cameraProviderFuture.get() // Preview val preview = Preview.Builder() .build() .also { it.setSurfaceProvider(viewFinder.createSurfaceProvider()) } imageCapture = ImageCapture.Builder().build() // Select back camera as a default val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA try { // Unbind use cases before rebinding cameraProvider.unbindAll() // Bind use cases to camera cameraProvider.bindToLifecycle( this , cameraSelector, preview, imageCapture ) } catch (exc: Exception) { Log.e(TAG, "Use case binding failed" , exc) } }, ContextCompat.getMainExecutor( this )) } private fun allPermissionsGranted() = REQUIRED_PERMISSIONS.all { ContextCompat.checkSelfPermission(baseContext, it) == PackageManager.PERMISSION_GRANTED } // creates a folder inside internal storage private fun getOutputDirectory(): File { val mediaDir = externalMediaDirs.firstOrNull()?.let { File(it, resources.getString(R.string.app_name)).apply { mkdirs() } } return if (mediaDir != null && mediaDir.exists()) mediaDir else filesDir } // checks the camera permission override fun onRequestPermissionsResult( requestCode: Int, permissions: Array<String>, grantResults: IntArray ) { if (requestCode == REQUEST_CODE_PERMISSIONS) { // If all permissions granted , then start Camera if (allPermissionsGranted()) { startCamera() } else { // If permissions are not granted, // present a toast to notify the user that // the permissions were not granted. Toast.makeText( this , "Permissions not granted by the user." , Toast.LENGTH_SHORT).show() finish() } } } companion object { private const val TAG = "CameraXGFG" private const val FILENAME_FORMAT = "yyyy-MM-dd-HH-mm-ss-SSS" private const val REQUEST_CODE_PERMISSIONS = 20 private val REQUIRED_PERMISSIONS = arrayOf(Manifest.permission.CAMERA) } override fun onDestroy() { super .onDestroy() cameraExecutor.shutdown() } } |