Android APIs
public static abstract class

CameraDevice.StateListener

extends Object
java.lang.Object
   ↳ android.hardware.camera2.CameraDevice.StateListener

Class Overview

A listener for notifications about the state of a camera device.

A listener must be provided to the openCamera(String, CameraDevice.StateListener, Handler) method to open a camera device.

These events include notifications about the device completing startup ( allowing for createCaptureSession(List, CameraCaptureSession.StateListener, Handler) 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.CaptureListener given to the capture(CaptureRequest, CameraCaptureSession.CaptureListener, Handler), captureBurst(List, CameraCaptureSession.CaptureListener, Handler), setRepeatingRequest(CaptureRequest, CameraCaptureSession.CaptureListener, Handler), or setRepeatingBurst(List, CameraCaptureSession.CaptureListener, Handler) methods.

See Also

Summary

Constants
int ERROR_CAMERA_DEVICE An error code that can be reported by onError(CameraDevice, int) indicating that the camera device has encountered a fatal error.
int ERROR_CAMERA_DISABLED An error code that can be reported by onError(CameraDevice, int) indicating that the camera device could not be opened due to a device policy.
int ERROR_CAMERA_IN_USE An error code that can be reported by onError(CameraDevice, int) indicating that the camera device is in use already.
int ERROR_CAMERA_SERVICE An error code that can be reported by onError(CameraDevice, int) indicating that the camera service has encountered a fatal error.
int ERROR_MAX_CAMERAS_IN_USE An error code that can be reported by onError(CameraDevice, int) indicating that the camera device could not be opened because there are too many other open camera devices.
Public Constructors
CameraDevice.StateListener()
Public Methods
void onActive(CameraDevice camera)
This method is deprecated. Use onActive(CameraCaptureSession) instead.
void onBusy(CameraDevice camera)
This method is deprecated. Use onConfigured(CameraCaptureSession) instead.
void onClosed(CameraDevice camera)
The method called when a camera device has been closed with close().
abstract void onDisconnected(CameraDevice camera)
The method called when a camera device is no longer available for use.
abstract void onError(CameraDevice camera, int error)
The method called when a camera device has encountered a serious error.
void onIdle(CameraDevice camera)
This method is deprecated. Use onReady(CameraCaptureSession) instead.
abstract void onOpened(CameraDevice camera)
The method called when a camera device has finished opening.
void onUnconfigured(CameraDevice camera)
This method is deprecated. Use onOpened(CameraDevice) instead.
[Expand]
Inherited Methods
From class java.lang.Object

Constants

public static final int ERROR_CAMERA_DEVICE

An error code that can be reported by onError(CameraDevice, int) indicating that the camera device has encountered a fatal error.

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

See Also
Constant Value: 4 (0x00000004)

public static final int ERROR_CAMERA_DISABLED

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

See Also
Constant Value: 3 (0x00000003)

public static final int ERROR_CAMERA_IN_USE

An error code that can be reported by onError(CameraDevice, int) indicating that the camera device is in use already.

This error can be produced when opening the camera fails.

See Also
Constant Value: 1 (0x00000001)

public static final int ERROR_CAMERA_SERVICE

An error code that can be reported by onError(CameraDevice, int) 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.

See Also
Constant Value: 5 (0x00000005)

public static final int ERROR_MAX_CAMERAS_IN_USE

An error code that can be reported by onError(CameraDevice, int) 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.

See Also
Constant Value: 2 (0x00000002)

Public Constructors

public CameraDevice.StateListener ()

Public Methods

public void onActive (CameraDevice camera)

This method is deprecated.
Use onActive(CameraCaptureSession) instead.

The method called when a camera device begins processing capture requests.

public void onBusy (CameraDevice camera)

This method is deprecated.
Use onConfigured(CameraCaptureSession) instead.

The method called when a camera device is busy.

public void onClosed (CameraDevice camera)

The method called when a camera device has been closed with 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 the camera device that has become closed

public abstract void onDisconnected (CameraDevice camera)

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

This callback may be called instead of onOpened(CameraDevice) 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 use case.

There may still be capture listener callbacks that are called 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 close() after this happens, as it is not recoverable until opening the camera again after it becomes available.

Parameters
camera the device that has been disconnected

public abstract void onError (CameraDevice camera, int error)

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

This callback may be called instead of onOpened(CameraDevice) 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 listeners that will be called after this error is received.

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

Parameters
camera The device reporting the error
error The error code, one of the StateListener.ERROR_* values.
See Also

public void onIdle (CameraDevice camera)

This method is deprecated.
Use onReady(CameraCaptureSession) instead.

The method called when a camera device has finished processing all submitted capture requests and has reached an idle state.

public abstract void onOpened (CameraDevice camera)

The method called when a camera device has finished opening.

At this point, the camera device is ready to use, and createCaptureSession(List, CameraCaptureSession.StateListener, Handler) can be called to set up the first capture session.

Parameters
camera the camera device that has become opened

public void onUnconfigured (CameraDevice camera)

This method is deprecated.
Use onOpened(CameraDevice) instead.

The method called when a camera device has no outputs configured.