Simple Camera App using CameraX Jetpack Compose

A camera app in Jetpack Compose allows you to create a custom user interface for capturing photos and interacting with the camera. By integrating Jetpack Compose with CameraX, you can build features such as live camera preview, photo capture, and camera switching.

Core Features of a Camera App with Jetpack Compose

CameraX Integration: CameraX is an Android Jetpack library that simplifies camera operations, enabling you to handle camera controls without needing in-depth knowledge of device-specific code. It provides features like live preview, image capture, and video recording. By using CameraX, you can focus on developing the UI with Compose.

Camera Permissions: As with any app that requires camera access, you must manage runtime permissions in your code. Jetpack Compose has built-in support to handle permissions by using ActivityResultContracts.RequestPermission to ask for the necessary camera permissions.

Embedding Camera Preview in Compose: To display the live camera feed, CameraX offers a PreviewView, which is a standard Android View component. You can embed this view in a Jetpack Compose layout using AndroidView, allowing the Compose UI to display the live camera preview.

Image Capture Button: With a capture button in Compose, you can trigger image capture functionality. When clicked, the button invokes the CameraX capture use case, saving or displaying the captured image as desired.

Image Preview Display: After capturing an image, you can show it using Compose's Image composable. This adds a seamless transition from live camera preview to a captured image within the same interface.

Basic Structure for a Camera App in Jetpack Compose

Here’s a sample code outline to help you get started with a CameraX-based camera app using Jetpack Compose:

@Composable
fun CameraScreen() {
    val context = LocalContext.current
    val lifecycleOwner = LocalLifecycleOwner.current
    val cameraProviderFuture = ProcessCameraProvider.getInstance(context)
    
    // Display live camera preview using AndroidView
    AndroidView(
        factory = { ctx ->
            val previewView = PreviewView(ctx)
            val cameraProvider = cameraProviderFuture.get()
            val preview = Preview.Builder().build()
            
            // Set up camera selector for back camera
            val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA
            
            preview.setSurfaceProvider(previewView.surfaceProvider)
            
            try {
                // Bind camera to lifecycle and set up preview
                cameraProvider.unbindAll()
                cameraProvider.bindToLifecycle(
                    lifecycleOwner,
                    cameraSelector,
                    preview
                )
            } catch (exc: Exception) {
                // Handle potential errors
            }
            
            previewView
        },
        modifier = Modifier.fillMaxSize()
    )

    // Button to capture image
    Button(onClick = {
        // Code to capture and save image
    }) {
        Text("Capture")
    }
}