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CameraManager

public final class CameraManager
extends Object

java.lang.Object
   ↳ android.hardware.camera2.CameraManager


A system service manager for detecting, characterizing, and connecting to CameraDevices.

For more details about communicating with camera devices, read the Camera developer guide or the camera2 package documentation.

Instances of this class must be obtained using Context.getSystemService(Class) with the argument CameraManager.class or Context.getSystemService(String) with the argument Context.CAMERA_SERVICE.

Summary

Nested classes

class CameraManager.AvailabilityCallback

A callback for camera devices becoming available or unavailable to open. 

class CameraManager.TorchCallback

A callback for camera flash torch modes becoming unavailable, disabled, or enabled. 

Public methods

CameraCharacteristics getCameraCharacteristics(String cameraId)

Query the capabilities of a camera device.

String[] getCameraIdList()

Return the list of currently connected camera devices by identifier, including cameras that may be in use by other camera API clients.

void openCamera(String cameraId, CameraDevice.StateCallback callback, Handler handler)

Open a connection to a camera with the given ID.

void openCamera(String cameraId, Executor executor, CameraDevice.StateCallback callback)

Open a connection to a camera with the given ID.

void registerAvailabilityCallback(Executor executor, CameraManager.AvailabilityCallback callback)

Register a callback to be notified about camera device availability.

void registerAvailabilityCallback(CameraManager.AvailabilityCallback callback, Handler handler)

Register a callback to be notified about camera device availability.

void registerTorchCallback(CameraManager.TorchCallback callback, Handler handler)

Register a callback to be notified about torch mode status.

void registerTorchCallback(Executor executor, CameraManager.TorchCallback callback)

Register a callback to be notified about torch mode status.

void setTorchMode(String cameraId, boolean enabled)

Set the flash unit's torch mode of the camera of the given ID without opening the camera device.

void unregisterAvailabilityCallback(CameraManager.AvailabilityCallback callback)

Remove a previously-added callback; the callback will no longer receive connection and disconnection callbacks.

void unregisterTorchCallback(CameraManager.TorchCallback callback)

Remove a previously-added callback; the callback will no longer receive torch mode status callbacks.

Inherited methods

Public methods

getCameraCharacteristics

added in API level 21
public CameraCharacteristics getCameraCharacteristics (String cameraId)

Query the capabilities of a camera device. These capabilities are immutable for a given camera.

Parameters
cameraId String: The id of the camera device to query

This value must never be null.

Returns
CameraCharacteristics The properties of the given camera

This value will never be null.

Throws
IllegalArgumentException if the cameraId does not match any known camera device.
CameraAccessException if the camera device has been disconnected.

getCameraIdList

added in API level 21
public String[] getCameraIdList ()

Return the list of currently connected camera devices by identifier, including cameras that may be in use by other camera API clients.

Non-removable cameras use integers starting at 0 for their identifiers, while removable cameras have a unique identifier for each individual device, even if they are the same model.

Returns
String[] The list of currently connected camera devices.

This value will never be null.

Throws
CameraAccessException

openCamera

added in API level 21
public void openCamera (String cameraId, 
                CameraDevice.StateCallback callback, 
                Handler handler)

Open a connection to a camera with the given ID.

Use getCameraIdList() to get the list of available camera devices. Note that even if an id is listed, open may fail if the device is disconnected between the calls to getCameraIdList() and openCamera(String, CameraDevice.StateCallback, Handler), or if a higher-priority camera API client begins using the camera device.

As of API level 23, devices for which the CameraManager.AvailabilityCallback.onCameraUnavailable(String) callback has been called due to the device being in use by a lower-priority, background camera API client can still potentially be opened by calling this method when the calling camera API client has a higher priority than the current camera API client using this device. In general, if the top, foreground activity is running within your application process, your process will be given the highest priority when accessing the camera, and this method will succeed even if the camera device is in use by another camera API client. Any lower-priority application that loses control of the camera in this way will receive an CameraDevice.StateCallback.onDisconnected(CameraDevice) callback.

Once the camera is successfully opened, CameraDevice.StateCallback.onOpened(CameraDevice) will be invoked with the newly opened CameraDevice. The camera device can then be set up for operation by calling CameraDevice.createCaptureSession(SessionConfiguration) and CameraDevice.createCaptureRequest(int)

If the camera becomes disconnected during initialization after this function call returns, CameraDevice.StateCallback.onDisconnected(CameraDevice) with a CameraDevice in the disconnected state (and CameraDevice.StateCallback.onOpened(CameraDevice) will be skipped).

If opening the camera device fails, then the device callback's onError method will be called, and subsequent calls on the camera device will throw a CameraAccessException.

Requires the CAMERA permission.

Parameters
cameraId String: The unique identifier of the camera device to open

This value must never be null.

callback CameraDevice.StateCallback: The callback which is invoked once the camera is opened

This value must never be null.

handler Handler: The handler on which the callback should be invoked, or null to use the current thread's looper.

Throws
CameraAccessException if the camera is disabled by device policy, has been disconnected, or is being used by a higher-priority camera API client.
IllegalArgumentException if cameraId or the callback was null, or the cameraId does not match any currently or previously available camera device.
SecurityException if the application does not have permission to access the camera

openCamera

added in API level 28
public void openCamera (String cameraId, 
                Executor executor, 
                CameraDevice.StateCallback callback)

Open a connection to a camera with the given ID.

The behavior of this method matches that of openCamera(String, StateCallback, Handler), except that it uses Executor as an argument instead of Handler.

Requires the CAMERA permission.

Parameters
cameraId String: The unique identifier of the camera device to open

This value must never be null.

executor Executor: The executor which will be used when invoking the callback.

This value must never be null.

Callback and listener events are dispatched through this Executor, providing an easy way to control which thread is used. To dispatch events through the main thread of your application, you can use Context.getMainExecutor(). To dispatch events through a shared thread pool, you can use AsyncTask.THREAD_POOL_EXECUTOR.

callback CameraDevice.StateCallback: The callback which is invoked once the camera is opened

This value must never be null.

Throws
CameraAccessException if the camera is disabled by device policy, has been disconnected, or is being used by a higher-priority camera API client.
IllegalArgumentException if cameraId, the callback or the executor was null, or the cameraId does not match any currently or previously available camera device.
SecurityException if the application does not have permission to access the camera

registerAvailabilityCallback

added in API level 28
public void registerAvailabilityCallback (Executor executor, 
                CameraManager.AvailabilityCallback callback)

Register a callback to be notified about camera device availability.

The behavior of this method matches that of registerAvailabilityCallback(AvailabilityCallback, Handler), except that it uses Executor as an argument instead of Handler.

Parameters
executor Executor: The executor which will be used to invoke the callback.

This value must never be null.

Callback and listener events are dispatched through this Executor, providing an easy way to control which thread is used. To dispatch events through the main thread of your application, you can use Context.getMainExecutor(). To dispatch events through a shared thread pool, you can use AsyncTask.THREAD_POOL_EXECUTOR.

callback CameraManager.AvailabilityCallback: the new callback to send camera availability notices to

This value must never be null.

Throws
IllegalArgumentException if the executor is null.

registerAvailabilityCallback

added in API level 21
public void registerAvailabilityCallback (CameraManager.AvailabilityCallback callback, 
                Handler handler)

Register a callback to be notified about camera device availability.

Registering the same callback again will replace the handler with the new one provided.

The first time a callback is registered, it is immediately called with the availability status of all currently known camera devices.

CameraManager.AvailabilityCallback.onCameraUnavailable(String) will be called whenever a camera device is opened by any camera API client. As of API level 23, other camera API clients may still be able to open such a camera device, evicting the existing client if they have higher priority than the existing client of a camera device. See open() for more details.

Since this callback will be registered with the camera service, remember to unregister it once it is no longer needed; otherwise the callback will continue to receive events indefinitely and it may prevent other resources from being released. Specifically, the callbacks will be invoked independently of the general activity lifecycle and independently of the state of individual CameraManager instances.

Parameters
callback CameraManager.AvailabilityCallback: the new callback to send camera availability notices to

This value must never be null.

handler Handler: The handler on which the callback should be invoked, or null to use the current thread's looper.

Throws
IllegalArgumentException if the handler is null but the current thread has no looper.

registerTorchCallback

added in API level 23
public void registerTorchCallback (CameraManager.TorchCallback callback, 
                Handler handler)

Register a callback to be notified about torch mode status.

Registering the same callback again will replace the handler with the new one provided.

The first time a callback is registered, it is immediately called with the torch mode status of all currently known camera devices with a flash unit.

Since this callback will be registered with the camera service, remember to unregister it once it is no longer needed; otherwise the callback will continue to receive events indefinitely and it may prevent other resources from being released. Specifically, the callbacks will be invoked independently of the general activity lifecycle and independently of the state of individual CameraManager instances.

Parameters
callback CameraManager.TorchCallback: The new callback to send torch mode status to

This value must never be null.

handler Handler: The handler on which the callback should be invoked, or null to use the current thread's looper.

Throws
IllegalArgumentException if the handler is null but the current thread has no looper.

registerTorchCallback

added in API level 28
public void registerTorchCallback (Executor executor, 
                CameraManager.TorchCallback callback)

Register a callback to be notified about torch mode status.

The behavior of this method matches that of registerTorchCallback(TorchCallback, Handler), except that it uses Executor as an argument instead of Handler.

Parameters
executor Executor: The executor which will be used to invoke the callback

This value must never be null.

Callback and listener events are dispatched through this Executor, providing an easy way to control which thread is used. To dispatch events through the main thread of your application, you can use Context.getMainExecutor(). To dispatch events through a shared thread pool, you can use AsyncTask.THREAD_POOL_EXECUTOR.

callback CameraManager.TorchCallback: The new callback to send torch mode status to

This value must never be null.

Throws
IllegalArgumentException if the executor is null.

setTorchMode

added in API level 23
public void setTorchMode (String cameraId, 
                boolean enabled)

Set the flash unit's torch mode of the camera of the given ID without opening the camera device.

Use getCameraIdList() to get the list of available camera devices and use getCameraCharacteristics(String) to check whether the camera device has a flash unit. Note that even if a camera device has a flash unit, turning on the torch mode may fail if the camera device or other camera resources needed to turn on the torch mode are in use.

If setTorchMode(String, boolean) is called to turn on or off the torch mode successfully, CameraManager.TorchCallback.onTorchModeChanged(String, boolean) will be invoked. However, even if turning on the torch mode is successful, the application does not have the exclusive ownership of the flash unit or the camera device. The torch mode will be turned off and becomes unavailable when the camera device that the flash unit belongs to becomes unavailable or when other camera resources to keep the torch on become unavailable ( CameraManager.TorchCallback.onTorchModeUnavailable(String) will be invoked). Also, other applications are free to call setTorchMode(String, boolean) to turn off the torch mode ( CameraManager.TorchCallback.onTorchModeChanged(String, boolean) will be invoked). If the latest application that turned on the torch mode exits, the torch mode will be turned off.

Parameters
cameraId String: The unique identifier of the camera device that the flash unit belongs to.

This value must never be null.

enabled boolean: The desired state of the torch mode for the target camera device. Set to true to turn on the torch mode. Set to false to turn off the torch mode.

Throws
CameraAccessException if it failed to access the flash unit. CameraAccessException.CAMERA_IN_USE will be thrown if the camera device is in use. CameraAccessException.MAX_CAMERAS_IN_USE will be thrown if other camera resources needed to turn on the torch mode are in use. CameraAccessException.CAMERA_DISCONNECTED will be thrown if camera service is not available.
IllegalArgumentException if cameraId was null, cameraId doesn't match any currently or previously available camera device, or the camera device doesn't have a flash unit.

unregisterAvailabilityCallback

added in API level 21
public void unregisterAvailabilityCallback (CameraManager.AvailabilityCallback callback)

Remove a previously-added callback; the callback will no longer receive connection and disconnection callbacks.

Removing a callback that isn't registered has no effect.

Parameters
callback CameraManager.AvailabilityCallback: The callback to remove from the notification list

This value must never be null.

unregisterTorchCallback

added in API level 23
public void unregisterTorchCallback (CameraManager.TorchCallback callback)

Remove a previously-added callback; the callback will no longer receive torch mode status callbacks.

Removing a callback that isn't registered has no effect.

Parameters
callback CameraManager.TorchCallback: The callback to remove from the notification list

This value must never be null.