CameraX 提供了一个 Extensions API,用于访问设备制造商在各种 Android 设备上实现的扩展。如需查看支持的扩展模式列表,请参阅相机扩展。
如需查看支持扩展的设备列表,请参阅支持的设备。
扩展架构
下图显示了相机扩展程序架构。
![](https://developer.android.google.cn/static/images/training/camera/camerax/camerax-camera-extensions-architecture.png?authuser=3&hl=sl)
CameraX 应用可以通过 CameraX Extensions API 使用扩展。CameraX Extensions API 可用于管理可用扩展的查询、配置扩展相机会话以及与相机扩展 OEM 库的通信。这样,您的应用就可以使用夜间、HDR、自动、焦外成像或脸部照片修复等功能。
启用图片拍摄和预览的扩展程序
在使用 Extensions API 之前,请使用 ExtensionsManager#getInstanceAsync(Context, CameraProvider) 方法检索 ExtensionsManager
实例。这样,您就可以查询扩展可用性信息。然后检索已启用扩展的 CameraSelector
。如在启用 CameraSelector
扩展的情况下调用 bindToLifecycle() 方法,将对图片拍摄和预览用例应用扩展模式。
如需实现图片拍摄和预览用例的扩展,请参阅以下代码示例:
Kotlin
import androidx.camera.extensions.ExtensionMode import androidx.camera.extensions.ExtensionsManager override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) val lifecycleOwner = this val cameraProviderFuture = ProcessCameraProvider.getInstance(applicationContext) cameraProviderFuture.addListener({ // Obtain an instance of a process camera provider // The camera provider provides access to the set of cameras associated with the device. // The camera obtained from the provider will be bound to the activity lifecycle. val cameraProvider = cameraProviderFuture.get() val extensionsManagerFuture = ExtensionsManager.getInstanceAsync(applicationContext, cameraProvider) extensionsManagerFuture.addListener({ // Obtain an instance of the extensions manager // The extensions manager enables a camera to use extension capabilities available on // the device. val extensionsManager = extensionsManagerFuture.get() // Select the camera val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA // Query if extension is available. // Not all devices will support extensions or might only support a subset of // extensions. if (extensionsManager.isExtensionAvailable(cameraSelector, ExtensionMode.NIGHT)) { // Unbind all use cases before enabling different extension modes. try { cameraProvider.unbindAll() // Retrieve a night extension enabled camera selector val nightCameraSelector = extensionsManager.getExtensionEnabledCameraSelector( cameraSelector, ExtensionMode.NIGHT ) // Bind image capture and preview use cases with the extension enabled camera // selector. val imageCapture = ImageCapture.Builder().build() val preview = Preview.Builder().build() // Connect the preview to receive the surface the camera outputs the frames // to. This will allow displaying the camera frames in either a TextureView // or SurfaceView. The SurfaceProvider can be obtained from the PreviewView. preview.setSurfaceProvider(surfaceProvider) // Returns an instance of the camera bound to the lifecycle // Use this camera object to control various operations with the camera // Example: flash, zoom, focus metering etc. val camera = cameraProvider.bindToLifecycle( lifecycleOwner, nightCameraSelector, imageCapture, preview ) } catch (e: Exception) { Log.e(TAG, "Use case binding failed", e) } } }, ContextCompat.getMainExecutor(this)) }, ContextCompat.getMainExecutor(this)) }
Java
import androidx.camera.extensions.ExtensionMode; import androidx.camera.extensions.ExtensionsManager; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); final LifecycleOwner lifecycleOwner = this; final ListenableFuturecameraProviderFuture = ProcessCameraProvider.getInstance(getApplicationContext()); cameraProviderFuture.addListener(() -> { try { // Obtain an instance of a process camera provider // The camera provider provides access to the set of cameras associated with the // device. The camera obtained from the provider will be bound to the activity // lifecycle. final ProcessCameraProvider cameraProvider = cameraProviderFuture.get(); final ListenableFuture extensionsManagerFuture = ExtensionsManager.getInstanceAsync(getApplicationContext(), cameraProvider); extensionsManagerFuture.addListener(() -> { // Obtain an instance of the extensions manager // The extensions manager enables a camera to use extension capabilities available // on the device. try { final ExtensionsManager extensionsManager = extensionsManagerFuture.get(); // Select the camera final CameraSelector cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA; // Query if extension is available. // Not all devices will support extensions or might only support a subset of // extensions. if (extensionsManager.isExtensionAvailable( cameraSelector, ExtensionMode.NIGHT )) { // Unbind all use cases before enabling different extension modes. cameraProvider.unbindAll(); // Retrieve extension enabled camera selector final CameraSelector nightCameraSelector = extensionsManager .getExtensionEnabledCameraSelector(cameraSelector, ExtensionMode.NIGHT); // Bind image capture and preview use cases with the extension enabled camera // selector. final ImageCapture imageCapture = new ImageCapture.Builder().build(); final Preview preview = new Preview.Builder().build(); // Connect the preview to receive the surface the camera outputs the frames // to. This will allow displaying the camera frames in either a TextureView // or SurfaceView. The SurfaceProvider can be obtained from the PreviewView. preview.setSurfaceProvider(surfaceProvider); cameraProvider.bindToLifecycle( lifecycleOwner, nightCameraSelector, imageCapture, preview ); } } catch (ExecutionException | InterruptedException e) { throw new RuntimeException(e); } }, ContextCompat.getMainExecutor(this)); } catch (ExecutionException | InterruptedException e) { throw new RuntimeException(e); } }, ContextCompat.getMainExecutor(this)); }
停用扩展程序
如需停用供应商扩展,请取消绑定所有用例,然后使用常规相机选择器重新绑定图片拍摄和预览用例。例如,使用 CameraSelector.DEFAULT_BACK_CAMERA
重新绑定到后置摄像头。
依赖项
CameraX Extensions API 是在 camera-extensions
库中实现的。这些扩展依赖于 CameraX 核心模块(core
、camera2
、lifecycle
)。
Groovy
dependencies { def camerax_version = "1.2.0-rc01" implementation "androidx.camera:camera-core:${camerax_version}" implementation "androidx.camera:camera-camera2:${camerax_version}" implementation "androidx.camera:camera-lifecycle:${camerax_version}" //the CameraX Extensions library implementation "androidx.camera:camera-extensions:${camerax_version}" ... }
Kotlin
dependencies { val camerax_version = "1.2.0-rc01" implementation("androidx.camera:camera-core:${camerax_version}") implementation("androidx.camera:camera-camera2:${camerax_version}") implementation("androidx.camera:camera-lifecycle:${camerax_version}") // the CameraX Extensions library implementation("androidx.camera:camera-extensions:${camerax_version}") ... }
移除旧版 API
1.0.0-alpha26
中发布了新版 Extensions API 后,2019 年 8 月发布的旧版 Extensions API 现已废弃。从版本 1.0.0-alpha28
开始,旧版 Extensions API 已从库中移除。现在,使用新版 Extensions API 的应用必须获取已启用扩展的 CameraSelector
,并使用它绑定用例。
使用旧版 Extensions API 的应用应改用新版 Extensions API,以确保日后能与即将推出的 CameraX 版本兼容。
其他资源
要详细了解 CameraX,请参阅下面列出的其他资源。
Codelab