CameraController


public abstract class CameraController

Known direct subclasses
LifecycleCameraController

A controller that provides most of the CameraX features.


The abstract base camera controller class.

This a high level controller that provides most of the CameraX core features in a single class. It handles camera initialization, creates and configures UseCases. It also listens to device motion sensor and set the target rotation for the use cases.

The controller is required to be used with a PreviewView. PreviewView provides the UI elements to display camera preview. The layout of the PreviewView is used to set the crop rect so the output from other use cases matches the preview display in a WYSIWYG way. The controller also listens to PreviewView's touch events to handle tap-to-focus and pinch-to-zoom features.

This class provides features of 4 UseCases: Preview, ImageCapture, ImageAnalysis and VideoCapture. Preview is required and always enabled. ImageCapture and ImageAnalysis are enabled by default. The video capture is disabled by default because it might affect other use cases, especially on lower end devices. It might be necessary to disable ImageCapture and/or ImageAnalysis before the video capture feature can be enabled. Disabling/enabling UseCases freezes the preview for a short period of time. To avoid the glitch, the UseCases need to be enabled/disabled before the controller is set on PreviewView.

Summary

Nested types

public final class CameraController.OutputSize

This class is deprecated.

Use ResolutionSelector instead.

Constants

static final int

This field is deprecated.

Use COORDINATE_SYSTEM_VIEW_REFERENCED instead.

static final int

Bitmask option to enable ImageAnalysis.

static final int

Bitmask option to enable ImageCapture.

static final int

The previous tap-to-focus action was failed to complete.

static final int

The previous tap-to-focus action was completed successfully and the camera is focused.

static final int

The previous tap-to-focus action was completed successfully but the camera is still unfocused, similar to the CONTROL_AF_STATE_NOT_FOCUSED_LOCKED state.

static final int

No tap-to-focus action has been started by the end user.

static final int

A tap-to-focus action has started but not completed.

static final int

Bitmask option to enable video capture use case.

Public methods

void

Removes all effects.

void

Removes a previously set analyzer.

@NonNull ListenableFuture<Void>
@MainThread
enableTorch(boolean torchEnabled)

Enable the torch or disable the torch.

@Nullable CameraControl

Gets the CameraControl of the currently attached camera.

@Nullable CameraInfo

Gets the CameraInfo of the currently attached camera.

@NonNull CameraSelector

Gets the CameraSelector.

@Nullable Executor

Gets the default executor for ImageAnalysis background tasks.

int

Returns the mode with which images are acquired.

int

Gets the image queue depth of ImageAnalysis.

int

Gets the output image format for ImageAnalysis.

@Nullable ResolutionSelector

Returns the ResolutionSelector for ImageAnalysis.

@Nullable CameraController.OutputSize

This method is deprecated.

Use getImageAnalysisResolutionSelector instead.

int

Gets the flash mode for ImageCapture.

@Nullable Executor

Gets the default executor for ImageCapture IO tasks.

int

Returns the image capture mode.

@Nullable ResolutionSelector

Returns the ResolutionSelector for ImageCapture.

@Nullable CameraController.OutputSize

This method is deprecated.

Use getImageCaptureResolutionSelector instead.

@NonNull ListenableFuture<Void>

Gets a ListenableFuture that completes when camera initialization completes.

@Nullable ResolutionSelector

Returns the ResolutionSelector for Preview.

@Nullable CameraController.OutputSize

This method is deprecated.

Use getPreviewResolutionSelector instead.

@NonNull LiveData<TapToFocusInfo>

Returns a LiveData with a TapToFocusInfo containing the latest focus state and corresponding tap position.

@NonNull LiveData<Integer>

This method is deprecated.

Use getTapToFocusInfoState instead.

@NonNull LiveData<Integer>

Returns a LiveData of current TorchState.

@NonNull DynamicRange

Gets the DynamicRange for video capture.

int

Gets the mirror mode for video capture.

@NonNull QualitySelector

Returns the QualitySelector for VIDEO_CAPTURE.

@NonNull Range<Integer>

Gets the target frame rate in frames per second for video capture.

@NonNull LiveData<ZoomState>

Returns a LiveData of ZoomState.

boolean

Checks if the given CameraSelector can be resolved to a camera.

boolean

Checks if ImageAnalysis is enabled.

boolean

Checks if ImageCapture is enabled.

boolean

Returns whether pinch-to-zoom is enabled.

boolean

Returns whether there is an in-progress video recording.

boolean

Returns whether tap-to-focus is enabled.

boolean

Checks if video capture is enabled.

void

Sets the CameraSelector.

void

Sets CameraEffect.

void
@MainThread
setEnabledUseCases(int enabledUseCases)

Enables or disables use cases.

void

Sets an analyzer to receive and analyze images.

void

Sets the executor that will be used for ImageAnalysis background tasks.

void

Sets the backpressure strategy to apply to the image producer to deal with scenarios where images may be produced faster than they can be analyzed.

void

Sets the image queue depth of ImageAnalysis.

void
@MainThread
setImageAnalysisOutputImageFormat(int imageAnalysisOutputImageFormat)

Sets the output image format for ImageAnalysis.

void

Sets the ResolutionSelector for ImageAnalysis.

void

This method is deprecated.

Use setImageAnalysisResolutionSelector instead.

void

Sets the flash mode for ImageCapture.

void

Sets the default executor that will be used for ImageCapture IO tasks.

void

Sets the image capture mode.

void

Sets the ResolutionSelector for ImageCapture.

void

This method is deprecated.

Use setImageCaptureResolutionSelector instead.

@NonNull ListenableFuture<Void>
@MainThread
setLinearZoom(@FloatRange(from = 0.0, to = 1.0) float linearZoom)

Sets current zoom by a linear zoom value ranging from 0f to 1.0f.

void

Enables/disables pinch-to-zoom.

void

Sets the ResolutionSelector for Preview.

void

This method is deprecated.

Use setPreviewResolutionSelector instead.

void
@MainThread
setTapToFocusAutoCancelDuration(
    @IntRange(from = 0) long duration,
    @NonNull TimeUnit timeUnit
)

Sets the auto-cancel duration for tap-to-focus events.

void

Enables/disables tap-to-focus.

void

Sets the DynamicRange for video capture.

void

Sets the mirror mode for video capture.

void

Sets the QualitySelector for VIDEO_CAPTURE.

void

Sets the target frame rate range in frames per second for video capture.

@NonNull ListenableFuture<Void>
@MainThread
setZoomRatio(float zoomRatio)

Sets current zoom by ratio.

@NonNull Recording
@RequiresApi(value = 26)
@MainThread
startRecording(
    @NonNull FileDescriptorOutputOptions outputOptions,
    @NonNull AudioConfig audioConfig,
    @NonNull Executor executor,
    @NonNull Consumer<VideoRecordEvent> listener
)

Takes a video to a given file descriptor.

@NonNull Recording
@MainThread
startRecording(
    @NonNull FileOutputOptions outputOptions,
    @NonNull AudioConfig audioConfig,
    @NonNull Executor executor,
    @NonNull Consumer<VideoRecordEvent> listener
)

Takes a video to a given file.

@NonNull Recording
@MainThread
startRecording(
    @NonNull MediaStoreOutputOptions outputOptions,
    @NonNull AudioConfig audioConfig,
    @NonNull Executor executor,
    @NonNull Consumer<VideoRecordEvent> listener
)

Takes a video to MediaStore.

void

Captures a new still image for in memory access.

void
@MainThread
takePicture(
    @NonNull ImageCapture.OutputFileOptions outputFileOptions,
    @NonNull Executor executor,
    @NonNull ImageCapture.OnImageSavedCallback imageSavedCallback
)

Captures a new still image and saves to a file along with application specified metadata.

Constants

COORDINATE_SYSTEM_VIEW_REFERENCED

Added in 1.1.0
Deprecated in 1.4.0
public static final int COORDINATE_SYSTEM_VIEW_REFERENCED = 1

ImageAnalysis.Analyzer option for returning PreviewView coordinates.

When the ImageAnalysis.Analyzer is configured with this option, it will receive a Matrix that will receive a value that represents the transformation from camera sensor to the PreviewView, which can be used for highlighting detected result in PreviewView. For example, laying over a bounding box on top of the detected face.

Note this option only works if the ImageAnalysis.Analyzer is set via setImageAnalysisAnalyzer. It will not be effective when used with camera-core directly.

IMAGE_ANALYSIS

Added in 1.1.0
public static final int IMAGE_ANALYSIS = 2

Bitmask option to enable ImageAnalysis. In setEnabledUseCases, if (enabledUseCases & IMAGE_ANALYSIS) != 0, then controller will enable image analysis features.

IMAGE_CAPTURE

Added in 1.1.0
public static final int IMAGE_CAPTURE = 1

Bitmask option to enable ImageCapture. In setEnabledUseCases, if (enabledUseCases & IMAGE_CAPTURE) != 0, then controller will enable image capture features.

TAP_TO_FOCUS_FAILED

Added in 1.1.0
public static final int TAP_TO_FOCUS_FAILED = 4

The previous tap-to-focus action was failed to complete. This is usually due to device limitations.

TAP_TO_FOCUS_FOCUSED

Added in 1.1.0
public static final int TAP_TO_FOCUS_FOCUSED = 2

The previous tap-to-focus action was completed successfully and the camera is focused.

TAP_TO_FOCUS_NOT_FOCUSED

Added in 1.1.0
public static final int TAP_TO_FOCUS_NOT_FOCUSED = 3

The previous tap-to-focus action was completed successfully but the camera is still unfocused, similar to the CONTROL_AF_STATE_NOT_FOCUSED_LOCKED state. The end user might be able to get a better result by trying again with different camera distances and/or lighting.

TAP_TO_FOCUS_NOT_STARTED

Added in 1.1.0
public static final int TAP_TO_FOCUS_NOT_STARTED = 0

No tap-to-focus action has been started by the end user.

TAP_TO_FOCUS_STARTED

Added in 1.1.0
public static final int TAP_TO_FOCUS_STARTED = 1

A tap-to-focus action has started but not completed. The app also gets notified with this state if a new action happens before the previous one could finish.

VIDEO_CAPTURE

Added in 1.1.0
public static final int VIDEO_CAPTURE = 4

Bitmask option to enable video capture use case. In setEnabledUseCases, if (enabledUseCases & VIDEO_CAPTURE) != 0, then controller will enable video capture features.

Public methods

clearEffects

Added in 1.3.0
@MainThread
public void clearEffects()

Removes all effects.

Once called, CameraX will remove all the effects and rebind the UseCase.

clearImageAnalysisAnalyzer

Added in 1.1.0
@MainThread
public void clearImageAnalysisAnalyzer()

Removes a previously set analyzer.

This will stop data from streaming to the ImageAnalysis.

If the current getDefaultTargetResolution returns non-null value, calling this method will reconfigure the camera which might cause additional latency. To avoid this, call this method when the lifecycle is not active.

See also
clearAnalyzer

enableTorch

Added in 1.1.0
@MainThread
public @NonNull ListenableFuture<VoidenableTorch(boolean torchEnabled)

Enable the torch or disable the torch.

If the value is set before the camera is ready, CameraController waits for the camera to be ready and then enables the torch.

Parameters
boolean torchEnabled

true to turn on the torch, false to turn it off.

Returns
@NonNull ListenableFuture<Void>

A ListenableFuture which is successful when the torch was changed to the value specified. It fails when it is unable to change the torch state. Cancellation of this future is a no-op.

See also
enableTorch

getCameraControl

Added in 1.1.0
@MainThread
public @Nullable CameraControl getCameraControl()

Gets the CameraControl of the currently attached camera.

For controls available directly through CameraController as well as CameraControl, it's recommended to use the ones with CameraController, e.g. setLinearZoom v.s. setLinearZoom. CameraControl is a lower-layer API and may require more steps to achieve the same effect, and will not maintain control values when switching between cameras.

Returns
@Nullable CameraControl

The CameraControl of the current camera. Returns null if camera is not ready.

See also
getCameraControl

getCameraInfo

Added in 1.1.0
@MainThread
public @Nullable CameraInfo getCameraInfo()

Gets the CameraInfo of the currently attached camera.

For info available directly through CameraController as well as CameraInfo, it's recommended to use the ones with CameraController, e.g. getTorchState v.s. getTorchState. CameraInfo is a lower-layer API and may require more steps to achieve the same effect, and will not maintain values when switching between cameras.

Returns
@Nullable CameraInfo

The CameraInfo of the current camera. Returns null if camera is not ready.

See also
getCameraInfo

getCameraSelector

Added in 1.1.0
@MainThread
public @NonNull CameraSelector getCameraSelector()

Gets the CameraSelector.

The default value isDEFAULT_BACK_CAMERA.

See also
CameraSelector

getImageAnalysisBackgroundExecutor

Added in 1.1.0
@MainThread
public @Nullable Executor getImageAnalysisBackgroundExecutor()

Gets the default executor for ImageAnalysis background tasks.

getImageAnalysisBackpressureStrategy

Added in 1.1.0
@MainThread
public int getImageAnalysisBackpressureStrategy()

Returns the mode with which images are acquired.

If not set, it defaults to STRATEGY_KEEP_ONLY_LATEST.

Returns
int

The backpressure strategy applied to the image producer.

getImageAnalysisImageQueueDepth

Added in 1.1.0
@MainThread
public int getImageAnalysisImageQueueDepth()

Gets the image queue depth of ImageAnalysis.

getImageAnalysisOutputImageFormat

Added in 1.4.0
@MainThread
public int getImageAnalysisOutputImageFormat()

Gets the output image format for ImageAnalysis.

The returned image format can be either OUTPUT_IMAGE_FORMAT_YUV_420_888, OUTPUT_IMAGE_FORMAT_RGBA_8888 or OUTPUT_IMAGE_FORMAT_NV21.

getImageAnalysisResolutionSelector

Added in 1.4.0
@MainThread
public @Nullable ResolutionSelector getImageAnalysisResolutionSelector()

Returns the ResolutionSelector for ImageAnalysis.

This method returns the value set by setImageAnalysisResolutionSelector. It returns null if the value has not been set.

getImageAnalysisTargetSize

Added in 1.1.0
Deprecated in 1.4.0
@MainThread
public @Nullable CameraController.OutputSize getImageAnalysisTargetSize()

Returns the intended output size for ImageAnalysis set by setImageAnalysisTargetSize, or null if not set.

getImageCaptureFlashMode

Added in 1.1.0
@MainThread
public int getImageCaptureFlashMode()

Gets the flash mode for ImageCapture.

Returns
int

the flashMode. Value is FLASH_MODE_AUTO, FLASH_MODE_ON, or FLASH_MODE_OFF.

See also
ImageCapture

getImageCaptureIoExecutor

Added in 1.1.0
@MainThread
public @Nullable Executor getImageCaptureIoExecutor()

Gets the default executor for ImageCapture IO tasks.

getImageCaptureMode

Added in 1.1.0
@MainThread
public int getImageCaptureMode()

Returns the image capture mode.

See also
getCaptureMode

getImageCaptureResolutionSelector

Added in 1.4.0
@MainThread
public @Nullable ResolutionSelector getImageCaptureResolutionSelector()

Returns the ResolutionSelector for ImageCapture.

This method returns the value set by setImageCaptureResolutionSelector (ResolutionSelector)}. It returns null if the value has not been set.

getImageCaptureTargetSize

Added in 1.1.0
Deprecated in 1.4.0
@MainThread
public @Nullable CameraController.OutputSize getImageCaptureTargetSize()

Returns the intended output size for ImageCapture set by setImageCaptureTargetSize, or null if not set.

getInitializationFuture

Added in 1.1.0
public @NonNull ListenableFuture<VoidgetInitializationFuture()

Gets a ListenableFuture that completes when camera initialization completes.

This future may fail with an InitializationException and associated cause that can be retrieved by getCause. The cause will be a CameraUnavailableException if it fails to access any camera during initialization.

In the rare case that the future fails with CameraUnavailableException, the camera will become unusable. This could happen for various reasons, for example hardware failure or the camera being held by another process. If the failure is temporary, killing and restarting the app might fix the issue.

The initialization also try to bind use cases before completing the ListenableFuture. The ListenableFuture will complete successfully regardless of whether the use cases are ready to be bound, e.g. it will complete successfully even if the controller is not set on a PreviewView. However the ListenableFuture will fail if the enabled use cases are not supported by the current camera.

See also
getInstance

getPreviewResolutionSelector

Added in 1.4.0
@MainThread
public @Nullable ResolutionSelector getPreviewResolutionSelector()

Returns the ResolutionSelector for Preview.

This method returns the value set by setPreviewResolutionSelector. It returns null if the value has not been set.

getPreviewTargetSize

Added in 1.1.0
Deprecated in 1.4.0
@MainThread
public @Nullable CameraController.OutputSize getPreviewTargetSize()

Returns the intended output size for Preview set by setPreviewTargetSize, or null if not set.

getTapToFocusInfoState

Added in 1.5.0-alpha06
@MainThread
public @NonNull LiveData<TapToFocusInfogetTapToFocusInfoState()

Returns a LiveData with a TapToFocusInfo containing the latest focus state and corresponding tap position.

When tap-to-focus feature is enabled, the LiveData will receive updates of focusing states. This usually happens when the end user taps on PreviewView, and then again when focusing is finished either successfully or unsuccessfully. The following table displays the states the LiveData can be in, and the possible transitions between them.

State Transition cause New State
TAP_TO_FOCUS_NOT_STARTED User taps on PreviewView TAP_TO_FOCUS_STARTED
TAP_TO_FOCUS_FOCUSED User taps on PreviewView TAP_TO_FOCUS_STARTED
TAP_TO_FOCUS_NOT_FOCUSED User taps on PreviewView TAP_TO_FOCUS_STARTED
TAP_TO_FOCUS_FAILED User taps on PreviewView TAP_TO_FOCUS_STARTED
TAP_TO_FOCUS_STARTED Focusing succeeded TAP_TO_FOCUS_FOCUSED
Focusing failed due to lighting and/or camera distance TAP_TO_FOCUS_NOT_FOCUSED
Focusing failed due to device constraints TAP_TO_FOCUS_FAILED
TAP_TO_FOCUS_FOCUSED Auto-cancel duration elapses TAP_TO_FOCUS_NOT_STARTED
TAP_TO_FOCUS_NOT_FOCUSED Auto-cancel duration elapses TAP_TO_FOCUS_NOT_STARTED
TAP_TO_FOCUS_FAILED Auto-cancel duration elapses TAP_TO_FOCUS_NOT_STARTED

getTapToFocusState

Added in 1.1.0
Deprecated in 1.5.0-alpha06
@MainThread
public @NonNull LiveData<IntegergetTapToFocusState()

Returns a LiveData with the latest tap-to-focus state.

When tap-to-focus feature is enabled, the LiveData will receive updates of focusing states. This happens when the end user taps on PreviewView, and then again when focusing is finished either successfully or unsuccessfully. The following table displays the states the LiveData can be in, and the possible transitions between them.

State Transition cause New State
TAP_TO_FOCUS_NOT_STARTED User taps on PreviewView TAP_TO_FOCUS_STARTED
TAP_TO_FOCUS_FOCUSED User taps on PreviewView TAP_TO_FOCUS_STARTED
TAP_TO_FOCUS_NOT_FOCUSED User taps on PreviewView TAP_TO_FOCUS_STARTED
TAP_TO_FOCUS_FAILED User taps on PreviewView TAP_TO_FOCUS_STARTED
TAP_TO_FOCUS_STARTED Focusing succeeded TAP_TO_FOCUS_FOCUSED
Focusing failed due to lighting and/or camera distance TAP_TO_FOCUS_NOT_FOCUSED
Focusing failed due to device constraints TAP_TO_FOCUS_FAILED
TAP_TO_FOCUS_FOCUSED Auto-cancel duration elapses TAP_TO_FOCUS_NOT_STARTED
TAP_TO_FOCUS_NOT_FOCUSED Auto-cancel duration elapses TAP_TO_FOCUS_NOT_STARTED
TAP_TO_FOCUS_FAILED Auto-cancel duration elapses TAP_TO_FOCUS_NOT_STARTED

getTorchState

Added in 1.1.0
@MainThread
public @NonNull LiveData<IntegergetTorchState()

Returns a LiveData of current TorchState.

The torch can be turned on and off via enableTorch which will trigger the change event to the returned LiveData.

Returns
@NonNull LiveData<Integer>

A LiveData containing current torch state.

See also
getTorchState

getVideoCaptureDynamicRange

Added in 1.4.0
@MainThread
public @NonNull DynamicRange getVideoCaptureDynamicRange()

Gets the DynamicRange for video capture.

getVideoCaptureMirrorMode

Added in 1.4.0
@MainThread
public int getVideoCaptureMirrorMode()

Gets the mirror mode for video capture.

getVideoCaptureQualitySelector

Added in 1.3.0
@MainThread
public @NonNull QualitySelector getVideoCaptureQualitySelector()

Returns the QualitySelector for VIDEO_CAPTURE.

Returns
@NonNull QualitySelector

the QualitySelector provided to setVideoCaptureQualitySelector or the default value of DEFAULT_QUALITY_SELECTOR if no quality selector was provided.

getVideoCaptureTargetFrameRate

Added in 1.4.0
@MainThread
public @NonNull Range<IntegergetVideoCaptureTargetFrameRate()

Gets the target frame rate in frames per second for video capture.

getZoomState

Added in 1.1.0
@MainThread
public @NonNull LiveData<ZoomStategetZoomState()

Returns a LiveData of ZoomState.

The LiveData will be updated whenever the set zoom state has been changed. This can occur when the application updates the zoom via setZoomRatio or setLinearZoom. The zoom state can also change anytime a camera starts up, for example when setCameraSelector is called.

See also
getZoomState

hasCamera

Added in 1.1.0
@MainThread
public boolean hasCamera(@NonNull CameraSelector cameraSelector)

Checks if the given CameraSelector can be resolved to a camera.

Use this method to check if the device has the given camera.

Only call this method after camera is initialized. e.g. after the ListenableFuture from getInitializationFuture is finished. Calling it prematurely throws IllegalStateException. Example:

controller.getInitializationFuture().addListener(() -> {
    if (controller.hasCamera(cameraSelector)) {
        controller.setCameraSelector(cameraSelector);
    } else {
        // Update UI if the camera is not available.
    }
    // Attach PreviewView after we know the camera is available.
    previewView.setController(controller);
}, ContextCompat.getMainExecutor(requireContext()));
Returns
boolean

true if the CameraSelector can be resolved to a camera.

Throws
java.lang.IllegalStateException

if the camera is not initialized.

isImageAnalysisEnabled

Added in 1.1.0
@MainThread
public boolean isImageAnalysisEnabled()

Checks if ImageAnalysis is enabled.

See also
ImageAnalysis

isImageCaptureEnabled

Added in 1.1.0
@MainThread
public boolean isImageCaptureEnabled()

Checks if ImageCapture is enabled.

ImageCapture is enabled by default. It has to be enabled before takePicture can be called.

See also
ImageCapture

isPinchToZoomEnabled

Added in 1.1.0
@MainThread
public boolean isPinchToZoomEnabled()

Returns whether pinch-to-zoom is enabled.

By default pinch-to-zoom is enabled.

Returns
boolean

true if pinch-to-zoom is enabled.

isRecording

Added in 1.1.0
@MainThread
public boolean isRecording()

Returns whether there is an in-progress video recording.

isTapToFocusEnabled

Added in 1.1.0
@MainThread
public boolean isTapToFocusEnabled()

Returns whether tap-to-focus is enabled.

By default tap-to-focus is enabled.

Returns
boolean

true if tap-to-focus is enabled.