CameraView

Kotlin |Java

class CameraView : FrameLayout

kotlin.Any
↳	android.view.View
	↳	android.view.ViewGroup
		↳	android.widget.FrameLayout
			↳	androidx.camera.view.CameraView

A View that displays a preview of the camera with methods , takePicture(ImageCapture.OutputFileOptions, Executor, OnImageSavedCallback), startRecording(File, Executor, OnVideoSavedCallback callback) and stopRecording().

Because the Camera is a limited resource and consumes a high amount of power, CameraView must be opened/closed. CameraView will handle opening/closing automatically through use of a . Use bindToLifecycle(LifecycleOwner) to start the camera.

Summary

Nested classes
	`CaptureMode` The capture mode used by CameraView.

Public constructors
`<init>(@NonNull context: Context)`
`<init>(@NonNull context: Context, @Nullable attrs: AttributeSet?)`
`<init>(@NonNull context: Context, @Nullable attrs: AttributeSet?, defStyle: Int)`
`<init>(@NonNull context: Context, @Nullable attrs: AttributeSet?, defStyleAttr: Int, defStyleRes: Int)`

Public methods
Unit	`bindToLifecycle(@NonNull lifecycleOwner: LifecycleOwner)` Binds control of the camera used by this view to the given lifecycle.
Unit	`enableTorch(torch: Boolean)` Turns on/off torch.
Int?	`getCameraLensFacing()` Returns the currently selected lensFacing.
CameraView.CaptureMode	`getCaptureMode()` Returns the scale type used to scale the preview.
Int	`getFlash()` Gets the active flash strategy.
Float	`getMaxZoomRatio()` Returns the maximum zoom ratio.
Float	`getMinZoomRatio()` Returns the minimum zoom ratio.
LiveData<PreviewView.StreamState!>	`getPreviewStreamState()` Gets the `LiveData` of the underlying `PreviewView`'s `PreviewView.StreamState`.
PreviewView.ScaleType	`getScaleType()` Returns the scale type used to scale the preview.
Float	`getZoomRatio()` Returns the current zoom ratio.
Boolean	`hasCameraWithLensFacing(lensFacing: Int)` Queries whether the current device has a camera with the specified direction.
Boolean	`isPinchToZoomEnabled()` Returns whether the view allows pinch-to-zoom.
Boolean	`isRecording()`
Boolean	`isTorchOn()` Returns current torch status.
Boolean	`isZoomSupported()` Returns whether the bound camera supports zooming.
Boolean	`onTouchEvent(@NonNull event: MotionEvent)`
Boolean	`performClick()` Focus the position of the touch event, or focus the center of the preview for accessibility events
Unit	`setCameraLensFacing(@Nullable lensFacing: Int?)` Sets the desired camera by specifying desired lensFacing.
Unit	`setCaptureMode(@NonNull captureMode: CameraView.CaptureMode)` Sets the CameraView capture mode
Unit	`setFlash(flashMode: Int)` Sets the active flash strategy.
Unit	`setPinchToZoomEnabled(enabled: Boolean)` Sets whether the view should allow pinch-to-zoom.
Unit	`setScaleType(@NonNull scaleType: PreviewView.ScaleType)` Sets the view finder scale type.
Unit	`setZoomRatio(zoomRatio: Float)` Sets the current zoom ratio.
Unit	`startRecording(@NonNull file: File, @NonNull executor: Executor, @NonNull callback: OnVideoSavedCallback)` Takes a video and calls the OnVideoSavedCallback when done.
Unit	`startRecording(@NonNull fd: ParcelFileDescriptor, @NonNull executor: Executor, @NonNull callback: OnVideoSavedCallback)` Takes a video and calls the OnVideoSavedCallback when done.
Unit	`startRecording(@NonNull outputFileOptions: OutputFileOptions, @NonNull executor: Executor, @NonNull callback: OnVideoSavedCallback)` Takes a video and calls the OnVideoSavedCallback when done.
Unit	`stopRecording()` Stops an in progress video.
Unit	`takePicture(@NonNull executor: Executor, @NonNull callback: ImageCapture.OnImageCapturedCallback)` Takes a picture, and calls `OnImageCapturedCallback#onCaptureSuccess(ImageProxy)` once when done.
Unit	`takePicture(@NonNull outputFileOptions: ImageCapture.OutputFileOptions, @NonNull executor: Executor, @NonNull callback: ImageCapture.OnImageSavedCallback)` Takes a picture and calls `OnImageSavedCallback#onImageSaved(ImageCapture.OutputFileResults)` when done.
Unit	`toggleCamera()` Toggles between the primary front facing camera and the primary back facing camera.

Protected methods
LayoutParams	`generateDefaultLayoutParams()`
Unit	`onAttachedToWindow()`
Unit	`onDetachedFromWindow()`
Unit	`onLayout(changed: Boolean, left: Int, top: Int, right: Int, bottom: Int)`
Unit	`onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int)`
Unit	`onRestoreInstanceState(@Nullable savedState: Parcelable?)`
Parcelable	`onSaveInstanceState()`

Public constructors

<init>

CameraView(@NonNull context: Context)

<init>

CameraView(
    @NonNull context: Context, 
    @Nullable attrs: AttributeSet?)

<init>

CameraView(
    @NonNull context: Context, 
    @Nullable attrs: AttributeSet?, 
    defStyle: Int)

<init>

CameraView(
    @NonNull context: Context, 
    @Nullable attrs: AttributeSet?, 
    defStyleAttr: Int, 
    defStyleRes: Int)

Public methods

bindToLifecycle

@RequiresPermission("android.permission.CAMERA") fun bindToLifecycle(@NonNull lifecycleOwner: LifecycleOwner): Unit

Binds control of the camera used by this view to the given lifecycle.

This links opening/closing the camera to the given lifecycle. The camera will not operate unless this method is called with a valid LifecycleOwner that is not in the state. Call this method only once camera permissions have been obtained.

Once the provided lifecycle has transitioned to a state, CameraView must be bound to a new lifecycle through this method in order to operate the camera.

Parameters
`lifecycleOwner`	LifecycleOwner: The lifecycle that will control this view's camera

Exceptions
`IllegalArgumentException`	if provided lifecycle is in a state.
`IllegalStateException`	if camera permissions are not granted.

enableTorch

fun enableTorch(torch: Boolean): Unit

Turns on/off torch.

Parameters
`torch`	Boolean: True to turn on torch, false to turn off torch.

getCameraLensFacing

@Nullable fun getCameraLensFacing(): Int?

Returns the currently selected lensFacing.

getCaptureMode

@NonNull fun getCaptureMode(): CameraView.CaptureMode

Returns the scale type used to scale the preview.

Return
`CameraView.CaptureMode`	The current `CaptureMode`.

getFlash

fun getFlash(): Int

Gets the active flash strategy.

getMaxZoomRatio

fun getMaxZoomRatio(): Float

Returns the maximum zoom ratio.

The zoom ratio corresponds to the ratio between both the widths and heights of a non-zoomed image and a maximally zoomed image for the selected camera.

Return
`Float`	The maximum zoom ratio.

getMinZoomRatio

fun getMinZoomRatio(): Float

Returns the minimum zoom ratio.

For most cameras this should return a zoom ratio of 1. A zoom ratio of 1 corresponds to a non-zoomed image.

Return
`Float`	The minimum zoom ratio.

getPreviewStreamState

@NonNull fun getPreviewStreamState(): LiveData<PreviewView.StreamState!>

Gets the LiveData of the underlying PreviewView's PreviewView.StreamState.

Return
`LiveData<PreviewView.StreamState!>`	A `LiveData` containing the `PreviewView.StreamState`. Apps can either get current value by `LiveData#getValue()` or register a observer by `LiveData#observe`.

See Also

PreviewView#getPreviewStreamState()

getScaleType

@NonNull fun getScaleType(): PreviewView.ScaleType

Returns the scale type used to scale the preview.

Return
`PreviewView.ScaleType`	The current `PreviewView.ScaleType`.

getZoomRatio

fun getZoomRatio(): Float

Returns the current zoom ratio.

Return
`Float`	The current zoom ratio.

hasCameraWithLensFacing

@RequiresPermission("android.permission.CAMERA") fun hasCameraWithLensFacing(lensFacing: Int): Boolean

Queries whether the current device has a camera with the specified direction.

Return
`Boolean`	True if the device supports the direction.

Exceptions
`IllegalStateException`	if the CAMERA permission is not currently granted.

isPinchToZoomEnabled

fun isPinchToZoomEnabled(): Boolean

Returns whether the view allows pinch-to-zoom.

Return
`Boolean`	True if pinch to zoom is enabled.

isRecording

fun isRecording(): Boolean

Return
`Boolean`	True if currently recording.

isTorchOn

fun isTorchOn(): Boolean

Returns current torch status.

Return
`Boolean`	true if torch is on , otherwise false

isZoomSupported

fun isZoomSupported(): Boolean

Returns whether the bound camera supports zooming.

Return
`Boolean`	True if the camera supports zooming.

onTouchEvent

fun onTouchEvent(@NonNull event: MotionEvent): Boolean

performClick

fun performClick(): Boolean

Focus the position of the touch event, or focus the center of the preview for accessibility events

setCameraLensFacing

fun setCameraLensFacing(@Nullable lensFacing: Int?): Unit

Sets the desired camera by specifying desired lensFacing.

This will choose the primary camera with the specified camera lensFacing.

If called before bindToLifecycle(LifecycleOwner), this will set the camera to be used when first bound to the lifecycle. If the specified lensFacing is not supported by the device, as determined by hasCameraWithLensFacing(int), the first supported lensFacing will be chosen when bindToLifecycle(LifecycleOwner) is called.

If called with null AFTER binding to the lifecycle, the behavior would be equivalent to unbind the use cases without the lifecycle having to be destroyed.

Parameters
`lensFacing`	Int?: The desired camera lensFacing.

setCaptureMode

fun setCaptureMode(@NonNull captureMode: CameraView.CaptureMode): Unit

Sets the CameraView capture mode

This controls only image or video capture function is enabled or both are enabled.

Parameters
`captureMode`	CameraView.CaptureMode: The desired `CaptureMode`.

setFlash

fun setFlash(flashMode: Int): Unit

Sets the active flash strategy.

setPinchToZoomEnabled

fun setPinchToZoomEnabled(enabled: Boolean): Unit

Sets whether the view should allow pinch-to-zoom.

When enabled, the user can pinch the camera to zoom in/out. This only has an effect if the bound camera supports zoom.

Parameters
`enabled`	Boolean: True to enable pinch-to-zoom.

setScaleType

fun setScaleType(@NonNull scaleType: PreviewView.ScaleType): Unit

Sets the view finder scale type.

This controls how the view finder should be scaled and positioned within the view.

Parameters
`scaleType`	PreviewView.ScaleType: The desired `PreviewView.ScaleType`.

setZoomRatio

fun setZoomRatio(zoomRatio: Float): Unit

Sets the current zoom ratio.

Valid zoom values range from getMinZoomRatio() to getMaxZoomRatio().

Parameters
`zoomRatio`