## Remove `Camera1` implementation
1. Delete all `android.hardware.Camera` instances.
2. Delete `SurfaceView` and `SurfaceHolder.Callback` implementations `surfaceCreated`, `surfaceChanged`, and `surfaceDestroyed`.
3. Remove custom lifecycle handling that opens or releases the camera in `onResume` or `onPause`.
4. Remove manual matrix calculations for orientation.
## Initialize `ProcessCameraProvider`
Request the `ProcessCameraProvider` and bind use cases to the Activity or
Fragment lifecycle.
```kotlin
val context = LocalContext.current
val lifecycleOwner = LocalLifecycleOwner.current
LaunchedEffect(context, lifecycleOwner) {
val cameraProvider = ProcessCameraProvider.getInstance(context).await()
val cameraSelector = CameraSelector.Builder()
.requireLensFacing(CameraSelector.LENS_FACING_BACK)
.build()
val preview = Preview.Builder().build()
val imageCapture = ImageCapture.Builder()
.setCaptureMode(ImageCapture.CAPTURE_MODE_MINIMIZE_LATENCY)
.build()
cameraProvider.unbindAll() // Unbind before rebinding
val camera = cameraProvider.bindToLifecycle(
lifecycleOwner,
cameraSelector,
preview,
imageCapture
)
val cameraControl = camera.cameraControl
}
```
## Implement the preview and tap-to-focus
Choose exactly one of the following patterns based on the app's UI toolkit:
### Option A: For Android Views
Use `androidx.camera.view.PreviewView`.
1. **Set up preview**:
```kotlin
preview.setSurfaceProvider(previewView.surfaceProvider)
```
2. **Handle tap-to-focus**:
```kotlin
val factory = previewView.meteringPointFactory
val point = factory.createPoint(x, y) // x, y from touch event
val action = FocusMeteringAction.Builder(point, FocusMeteringAction.FLAG_AF).build()
cameraControl?.startFocusAndMetering(action)
```
### Option B: For Jetpack Compose
Use `androidx.camera.compose.CameraXViewfinder`.
1. **Set up preview and SurfaceRequest**:
```kotlin
var surfaceRequest by remember { mutableStateOf(null) }
val preview = remember {
Preview.Builder().build().apply {
setSurfaceProvider { request -> surfaceRequest = request }
}
}
```
2. **Render viewfinder**:
```kotlin
surfaceRequest?.let { request ->
CameraXViewfinder(
surfaceRequest = request,
coordinateTransformer = coordinateTransformer,
modifier = Modifier
)
}
```
3. **Handle tap-to-focus in Compose**:
```kotlin
// Inside your tap gesture handler...
val surfaceCoords = with(coordinateTransformer) { offset.transform() }
val factory = SurfaceOrientedMeteringPointFactory(
request.resolution.width.toFloat(),
request.resolution.height.toFloat()
)
val point = factory.createPoint(surfaceCoords.x, surfaceCoords.y)
val action = FocusMeteringAction.Builder(point, FocusMeteringAction.FLAG_AF).build()
cameraControl?.startFocusAndMetering(action)
```
4. **Update target rotation for Compose**:
```kotlin
LaunchedEffect(configuration) {
if (!view.isInEditMode) {
val rotation = view.display?.rotation ?: Surface.ROTATION_0
imageCapture.targetRotation = rotation
preview.targetRotation = rotation
}
}
```
## Capture a photo
Use the `ImageCapture` use case to take the picture. The `ImageProxy` handles
rotation directly.
```kotlin
imageCapture.takePicture(
cameraExecutor,
object : ImageCapture.OnImageCapturedCallback() {
override fun onCaptureSuccess(image: ImageProxy) {
val buffer = image.planes[0].buffer
val bytes = ByteArray(buffer.remaining())
buffer.get(bytes)
val bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.size)
// Adjust rotation natively via ImageProxy
val matrix = Matrix()
matrix.postRotate(image.imageInfo.rotationDegrees.toFloat())
if (lensFacing == CameraSelector.LENS_FACING_FRONT) {
matrix.postScale(-1f, 1f) // Mirror for front camera
}
val rotatedBitmap = Bitmap.createBitmap(
bitmap, 0, 0, bitmap.width, bitmap.height, matrix, true
)
// MUST close proxy
image.close()
}
override fun onError(exception: ImageCaptureException) {
Log.e("CameraX", "Capture failed: ${exception.message}", exception)
}
}
)
```
## Switch cameras
To flip between front and rear cameras, change the `CameraSelector` and
retrigger the `ProcessCameraProvider` logic.
```kotlin
lensFacing = if (lensFacing == CameraSelector.LENS_FACING_BACK) {
CameraSelector.LENS_FACING_FRONT
} else {
CameraSelector.LENS_FACING_BACK
}
```
## Follow constraints
- **Don't manage the camera lifecycle manually** : Bind the camera to a `LifecycleOwner` through the `ProcessCameraProvider`. Avoid manual camera open or close logic in `onResume` or `onPause`.
- **Don't calculate focus matrices manually** : `MeteringPointFactory` handles coordinate transformations, including device rotation offsets. Avoid custom matrix implementations.
- **Don't forget to close the `ImageProxy`** : Remember to invoke `image.close()` in the capture callback. Skipping this call locks the capture pipeline and interrupts subsequent photos.
- **Don't wrap `PreviewView` in `AndroidView` for Compose code** : For Compose UI layouts, use `CameraXViewfinder`. Compiling `PreviewView` in an `AndroidView` is an earlier fallback option that introduces resizing issues.