How to Create Custom Camera using CameraX in Android?

Rohit Garg

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Jun 12, 2024

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Let’s start…

Add Dependency:

Add CameraX Dependency First. We need to add the CameraX dependency to our project. To do this, we need to add the following code to our build.gradle file:

def camerax_version = "1.2.1"
// 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:$camerax_version"

Set Up Permission:

Set Up Camera Permissions Next. Need to set up camera permissions in our application’s manifest file. We need to add the following code to our manifest file:

<uses-permission android:name="android.permission.CAMERA" />

<uses-feature android:name="android.hardware.camera" />

Check Permission in Activity file:

In our activity class first we will have to check camera permission. Through allpermissionsGranted() function we are requesting for Camera permission and onRequestPermissionsResult() if all permissions granted , then we will start Camera by startCamera() function.

private lateinit var mViewBinding: ActivityMainBinding
    private val TAG = "CameraXBasic"
    private var imageCapture: ImageCapture? = null
    private val REQUEST_CODE_PERMISSIONS = 20
    private val REQUIRED_PERMISSIONS = arrayOf(Manifest.permission.CAMERA)

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    mViewBinding = ActivityMainBinding.inflate(layoutInflater)
    setContentView(mViewBinding.root)    if (allPermissionsGranted()) {
        startCamera()
    } else {
        ActivityCompat.requestPermissions(this, REQUIRED_PERMISSIONS, REQUEST_CODE_PERMISSIONS)
    }
}private fun allPermissionsGranted() = REQUIRED_PERMISSIONS.all {
    ContextCompat.checkSelfPermission(baseContext, it) == PackageManager.PERMISSION_GRANTED
}// checks the camera permission
override fun onRequestPermissionsResult(
    requestCode: Int, permissions: Array<String>, grantResults:
    IntArray
) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults)
    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()
        }
    }
}

Let’s take a close look at our startCamera() function.

• cameraProvider is using to bind the lifecycle of cameras to the lifecycle owner.
• preview is to set the preview in View layout element of camera preview.
• Here we are selecting the back camera as a default camera by DEFAULT_BACK_CAMERA.
• cameraProvider.bindToLifecycle binds use cases to camera.

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(mViewBinding.viewFinder.surfaceProvider)
            }        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))
}

That’s it. Now we are good to work with CameraX preview.