SensorDirectChannel

RATE_FAST

static val RATE_FAST: Int

Sensor operates at nominal rate of 200Hz. The actual rate is expected to be between 55% to 220% of nominal rate, thus between 110Hz to 440Hz.

Value: 2

RATE_NORMAL

static val RATE_NORMAL: Int

Sensor operates at nominal rate of 50Hz. The actual rate is expected to be between 55% to 220% of nominal rate, thus between 27.5Hz to 110Hz.

Value: 1

RATE_STOP

static val RATE_STOP: Int

Sensor stopped (no event output).

Value: 0

RATE_VERY_FAST

static val RATE_VERY_FAST: Int

Sensor operates at nominal rate of 800Hz. The actual rate is expected to be between 55% to 220% of nominal rate, thus between 440Hz to 1760Hz.

Value: 3

TYPE_HARDWARE_BUFFER

static val TYPE_HARDWARE_BUFFER: Int

Shared memory type wrapped by HardwareBuffer object.

Value: 2

TYPE_MEMORY_FILE

static val TYPE_MEMORY_FILE: Int

Shared memory type ashmem, wrapped in MemoryFile object.

Value: 1

close

fun close(): Unit

Close sensor direct channel. Stop all active sensor in the channel and free sensor system resource related to channel. Shared memory used for creating the direct channel need to be closed or freed separately.

configure

fun configure(
    sensor: Sensor!, 
    rateLevel: Int
): Int

Configure sensor rate or stop sensor report. To start event report of a sensor, or change rate of existing report, call this function with rateLevel other than RATE_STOP. Sensor events will be added into a queue formed by the shared memory used in creation of direction channel. Each element of the queue has size of 104 bytes and represents a sensor event. Data structure of an element (all fields in little-endian):

offset   type                    name
  ------------------------------------------------------------------------
    0x0000   int32_t                 size (always 104)
    0x0004   int32_t                 sensor report token
    0x0008   int32_t                 type (see SensorType)
    0x000C   uint32_t                atomic counter
    0x0010   int64_t                 timestamp (see Event)
    0x0018   float[16]/int64_t[8]    data (data type depends on sensor type)
    0x0058   int32_t[4]              reserved (set to zero)
  

isOpen

fun isOpen(): Boolean

Determine if a channel is still valid. A channel is invalidated after #close() is called.

finalize

protected fun finalize(): Unit

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. A subclass overrides the finalize method to dispose of system resources or to perform other cleanup.

The general contract of finalize is that it is invoked if and when the Java virtual machine has determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, except as a result of an action taken by the finalization of some other object or class which is ready to be finalized. The finalize method may take any action, including making this object available again to other threads; the usual purpose of finalize, however, is to perform cleanup actions before the object is irrevocably discarded. For example, the finalize method for an object that represents an input/output connection might perform explicit I/O transactions to break the connection before the object is permanently discarded.

The finalize method of class Object performs no special action; it simply returns normally. Subclasses of Object may override this definition.

The Java programming language does not guarantee which thread will invoke the finalize method for any given object. It is guaranteed, however, that the thread that invokes finalize will not be holding any user-visible synchronization locks when finalize is invoked. If an uncaught exception is thrown by the finalize method, the exception is ignored and finalization of that object terminates.

After the finalize method has been invoked for an object, no further action is taken until the Java virtual machine has again determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, including possible actions by other objects or classes which are ready to be finalized, at which point the object may be discarded.

The finalize method is never invoked more than once by a Java virtual machine for any given object.

Any exception thrown by the finalize method causes the finalization of this object to be halted, but is otherwise ignored.