StateCallback

Kotlin |Java

abstract class StateCallback

kotlin.Any
↳	android.hardware.camera2.CameraDevice.StateCallback

A callback objects for receiving updates about the state of a camera device.

A callback instance must be provided to the android.hardware.camera2.CameraManager#openCamera method to open a camera device.

These state updates include notifications about the device completing startup ( allowing for #createCaptureSession to be called), about device disconnection or closure, and about unexpected device errors.

Events about the progress of specific CaptureRequests are provided through a CameraCaptureSession.CaptureCallback given to the CameraCaptureSession#capture, CameraCaptureSession#captureBurst, CameraCaptureSession#setRepeatingRequest, or CameraCaptureSession#setRepeatingBurst methods.

Summary

Constants
static Int	`ERROR_CAMERA_DEVICE` An error code that can be reported by `onError` indicating that the camera device has encountered a fatal error.
static Int	`ERROR_CAMERA_DISABLED` An error code that can be reported by `onError` indicating that the camera device could not be opened due to a device policy.
static Int	`ERROR_CAMERA_IN_USE` An error code that can be reported by `onError` indicating that the camera device is in use already.
static Int	`ERROR_CAMERA_SERVICE` An error code that can be reported by `onError` indicating that the camera service has encountered a fatal error.
static Int	`ERROR_MAX_CAMERAS_IN_USE` An error code that can be reported by `onError` indicating that the camera device could not be opened because there are too many other open camera devices.

Public constructors
`StateCallback()`

Public methods
open Unit	`onClosed(camera: CameraDevice)` The method called when a camera device has been closed with `CameraDevice#close`.
abstract Unit	`onDisconnected(camera: CameraDevice)` The method called when a camera device is no longer available for use.
abstract Unit	`onError(camera: CameraDevice, error: Int)` The method called when a camera device has encountered a serious error.
abstract Unit	`onOpened(camera: CameraDevice)` The method called when a camera device has finished opening.

Constants

ERROR_CAMERA_DEVICE

Added in API level 21

static val ERROR_CAMERA_DEVICE: Int

An error code that can be reported by onError indicating that the camera device has encountered a fatal error.

The camera device needs to be re-opened to be used again.

Value: 4

See Also

#onError

ERROR_CAMERA_DISABLED

Added in API level 21

static val ERROR_CAMERA_DISABLED: Int

An error code that can be reported by onError indicating that the camera device could not be opened due to a device policy.

Value: 3

See Also

ERROR_CAMERA_IN_USE

Added in API level 21

static val ERROR_CAMERA_IN_USE: Int

An error code that can be reported by onError indicating that the camera device is in use already.

This error can be produced when opening the camera fails due to the camera being used by a higher-priority camera API client.

Value: 1

See Also

#onError

ERROR_CAMERA_SERVICE

Added in API level 21

static val ERROR_CAMERA_SERVICE: Int

An error code that can be reported by onError indicating that the camera service has encountered a fatal error.

The Android device may need to be shut down and restarted to restore camera function, or there may be a persistent hardware problem.

An attempt at recovery may be possible by closing the CameraDevice and the CameraManager, and trying to acquire all resources again from scratch.

Value: 5

See Also

#onError

ERROR_MAX_CAMERAS_IN_USE

Added in API level 21

static val ERROR_MAX_CAMERAS_IN_USE: Int

An error code that can be reported by onError indicating that the camera device could not be opened because there are too many other open camera devices.

The system-wide limit for number of open cameras has been reached, and more camera devices cannot be opened until previous instances are closed.

This error can be produced when opening the camera fails.

Value: 2

See Also

#onError

Public constructors

StateCallback

StateCallback()

Public methods

onClosed

Added in API level 21

open fun onClosed(camera: CameraDevice): Unit

The method called when a camera device has been closed with CameraDevice#close.

Any attempt to call methods on this CameraDevice in the future will throw a IllegalStateException.

The default implementation of this method does nothing.

Parameters
`camera`	CameraDevice: the camera device that has become closed This value cannot be `null`.

onDisconnected

Added in API level 21

abstract fun onDisconnected(camera: CameraDevice): Unit

The method called when a camera device is no longer available for use.

This callback may be called instead of onOpened if opening the camera fails.

Any attempt to call methods on this CameraDevice will throw a CameraAccessException. The disconnection could be due to a change in security policy or permissions; the physical disconnection of a removable camera device; or the camera being needed for a higher-priority camera API client.

There may still be capture callbacks that are invoked after this method is called, or new image buffers that are delivered to active outputs.

The default implementation logs a notice to the system log about the disconnection.

You should clean up the camera with CameraDevice#close after this happens, as it is not recoverable until the camera can be opened again. For most use cases, this will be when the camera again becomes available.

Parameters
`camera`	CameraDevice: the device that has been disconnected This value cannot be `null`.

onError

Added in API level 21

abstract fun onError(
    camera: CameraDevice, 
    error: Int
): Unit

The method called when a camera device has encountered a serious error.

This callback may be called instead of onOpened if opening the camera fails.

This indicates a failure of the camera device or camera service in some way. Any attempt to call methods on this CameraDevice in the future will throw a CameraAccessException with the CAMERA_ERROR reason.

There may still be capture completion or camera stream callbacks that will be called after this error is received.

You should clean up the camera with CameraDevice#close after this happens. Further attempts at recovery are error-code specific.

Parameters

camera CameraDevice: The device reporting the error This value cannot be null.

error Int: The error code. Value is android.hardware.camera2.CameraDevice.StateCallback#ERROR_CAMERA_IN_USE, android.hardware.camera2.CameraDevice.StateCallback#ERROR_MAX_CAMERAS_IN_USE, android.hardware.camera2.CameraDevice.StateCallback#ERROR_CAMERA_DISABLED, android.hardware.camera2.CameraDevice.StateCallback#ERROR_CAMERA_DEVICE, or android.hardware.camera2.CameraDevice.StateCallback#ERROR_CAMERA_SERVICE

Parameters
`camera`	CameraDevice: The device reporting the error This value cannot be `null`.
`error`	Int: The error code. Value is `android.hardware.camera2.CameraDevice.StateCallback#ERROR_CAMERA_IN_USE`, `android.hardware.camera2.CameraDevice.StateCallback#ERROR_MAX_CAMERAS_IN_USE`, `android.hardware.camera2.CameraDevice.StateCallback#ERROR_CAMERA_DISABLED`, `android.hardware.camera2.CameraDevice.StateCallback#ERROR_CAMERA_DEVICE`, or `android.hardware.camera2.CameraDevice.StateCallback#ERROR_CAMERA_SERVICE`

See Also

#ERROR_CAMERA_IN_USE
#ERROR_MAX_CAMERAS_IN_USE
#ERROR_CAMERA_DISABLED
#ERROR_CAMERA_DEVICE
#ERROR_CAMERA_SERVICE

onOpened

Added in API level 21

abstract fun onOpened(camera: CameraDevice): Unit

The method called when a camera device has finished opening.

At this point, the camera device is ready to use, and android.hardware.camera2.CameraDevice#createCaptureSession can be called to set up the first capture session.

Parameters
`camera`	CameraDevice: the camera device that has become opened This value cannot be `null`.