camera1-to-camerax
Use this skill to migrate legacy Android camera implementations (Camera1 or raw Camera2 APIs) to CameraX. CameraX is a lifecycle-aware Jetpack library built on top of Camera2 that resolves camera rotation issues and handles device dependencies.
Skill body
Step 0: Add Dependencies
Check for and add the required CameraX dependencies. Use version 1.3.0 or higher for interoperability, or version 1.5.0 or higher for Compose extensions.
If you are using a Version Catalog (libs.versions.toml), add the following:
[versions]
camerax = "<minimum_version_needed>"
[libraries]
androidx-camera-core = { group = "androidx.camera", name = "camera-core", version.ref = "camerax" }
androidx-camera-camera2 = { group = "androidx.camera", name = "camera-camera2", version.ref = "camerax" }
androidx-camera-lifecycle = { group = "androidx.camera", name = "camera-lifecycle", version.ref = "camerax" }
androidx-camera-view = { group = "androidx.camera", name = "camera-view", version.ref = "camerax" }
androidx-camera-compose = { group = "androidx.camera", name = "camera-compose", version.ref = "camerax" }
And in your build.gradle.kts (or build.gradle):
implementation(libs.androidx.camera.core)
implementation(libs.androidx.camera.camera2)
implementation(libs.androidx.camera.lifecycle)
implementation(libs.androidx.camera.view)
implementation(libs.androidx.camera.compose)
Without a Version Catalog, fall back to these standard Gradle dependencies:
implementation "androidx.camera:camera-core:<minimum_version_needed>"
implementation "androidx.camera:camera-camera2:<minimum_version_needed>"
implementation "androidx.camera:camera-lifecycle:<minimum_version_needed>"
implementation "androidx.camera:camera-view:<minimum_version_needed>"
implementation "androidx.camera:camera-compose:<minimum_version_needed>"
Step 1: Remove Legacy Implementation
- Delete all
android.hardware.Camerainstances. - Delete
SurfaceViewandSurfaceHolder.Callbackimplementations (surfaceCreated,surfaceChanged,surfaceDestroyed). - Remove custom lifecycle handling that opens or releases the camera in
onResumeoronPause. - Remove manual matrix calculations for orientation.
Step 2: Initialize ProcessCameraProvider
Request the ProcessCameraProvider and bind use cases to the Activity or
Fragment lifecycle.
val context = LocalContext.current
val lifecycleOwner = LocalLifecycleOwner.current
LaunchedEffect(context, lifecycleOwner) {
val cameraProviderFuture = ProcessCameraProvider.getInstance(context)
cameraProviderFuture.addListener({
val cameraProvider = cameraProviderFuture.get()
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
}, ContextCompat.getMainExecutor(context)
)
}
Step 3: Implement the Preview \& Tap-to-Focus
Choose exactly one of the following patterns based on the app’s UI toolkit:
Option A: For Android Views (XML Legacy)
Use androidx.camera.view.PreviewView.
1. Set up preview:
preview.setSurfaceProvider(previewView.surfaceProvider)
2. Handle tap-to-focus:
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:
var surfaceRequest by remember { mutableStateOf<SurfaceRequest?>(null) }
val preview = remember {
Preview.Builder().build().apply {
setSurfaceProvider { request -> surfaceRequest = request }
}
}
2. Render viewfinder:
surfaceRequest?.let { request ->
CameraXViewfinder(
surfaceRequest = request,
coordinateTransformer = coordinateTransformer,
modifier = Modifier
)
}
3. Handle tap-to-focus in Compose:
// 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:
LaunchedEffect(configuration) {
if (!view.isInEditMode) {
val rotation = view.display?.rotation ?: Surface.ROTATION_0
imageCapture.targetRotation = rotation
preview.targetRotation = rotation
}
}
Step 4: Capture Photo
Use the ImageCapture use case to take the picture. The ImageProxy handles
rotation directly.
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)
}
}
)
Step 5: Switch Cameras
To flip between front and rear cameras, change the CameraSelector and
re-trigger the ProcessCameraProvider logic.
lensFacing = if (lensFacing == CameraSelector.LENS_FACING_BACK) {
CameraSelector.LENS_FACING_FRONT
} else {
CameraSelector.LENS_FACING_BACK
}
Constraints
- Don’t manage the camera lifecycle manually : Bind the camera to a
LifecycleOwnerthrough theProcessCameraProvider. Avoid manual camera open or close logic inonResumeoronPause. - Don’t calculate focus matrices manually :
MeteringPointFactoryhandles 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
PreviewViewinAndroidViewfor Compose code : For Compose UI layouts, useCameraXViewfinder. CompilingPreviewViewin anAndroidViewis an old fallback option that introduces resizing issues.
Skill frontmatter
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