native/include/android/input.h

/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef _ANDROID_INPUT_H
#define _ANDROID_INPUT_H

/******************************************************************
 *
 * IMPORTANT NOTICE:
 *
 *   This file is part of Android's set of stable system headers
 *   exposed by the Android NDK (Native Development Kit).
 *
 *   Third-party source AND binary code relies on the definitions
 *   here to be FROZEN ON ALL UPCOMING PLATFORM RELEASES.
 *
 *   - DO NOT MODIFY ENUMS (EXCEPT IF YOU ADD NEW 32-BIT VALUES)
 *   - DO NOT MODIFY CONSTANTS OR FUNCTIONAL MACROS
 *   - DO NOT CHANGE THE SIGNATURE OF FUNCTIONS IN ANY WAY
 *   - DO NOT CHANGE THE LAYOUT OR SIZE OF STRUCTURES
 */

/*
 * Structures and functions to receive and process input events in
 * native code.
 *
 * NOTE: These functions MUST be implemented by /system/lib/libui.so
 */

#include <sys/types.h>
#include <android/keycodes.h>
#include <android/looper.h>

#ifdef __cplusplus
extern "C" {
#endif

/*
 * Key states (may be returned by queries about the current state of a
 * particular key code, scan code or switch).
 */
enum {
    /* The key state is unknown or the requested key itself is not supported. */
    AKEY_STATE_UNKNOWN = -1,

    /* The key is up. */
    AKEY_STATE_UP = 0,

    /* The key is down. */
    AKEY_STATE_DOWN = 1,

    /* The key is down but is a virtual key press that is being emulated by the system. */
    AKEY_STATE_VIRTUAL = 2
};

/*
 * Meta key / modifer state.
 */
enum {
    /* No meta keys are pressed. */
    AMETA_NONE = 0,

    /* This mask is used to check whether one of the ALT meta keys is pressed. */
    AMETA_ALT_ON = 0x02,

    /* This mask is used to check whether the left ALT meta key is pressed. */
    AMETA_ALT_LEFT_ON = 0x10,

    /* This mask is used to check whether the right ALT meta key is pressed. */
    AMETA_ALT_RIGHT_ON = 0x20,

    /* This mask is used to check whether one of the SHIFT meta keys is pressed. */
    AMETA_SHIFT_ON = 0x01,

    /* This mask is used to check whether the left SHIFT meta key is pressed. */
    AMETA_SHIFT_LEFT_ON = 0x40,

    /* This mask is used to check whether the right SHIFT meta key is pressed. */
    AMETA_SHIFT_RIGHT_ON = 0x80,

    /* This mask is used to check whether the SYM meta key is pressed. */
    AMETA_SYM_ON = 0x04
};

/*
 * Input events.
 *
 * Input events are opaque structures.  Use the provided accessors functions to
 * read their properties.
 */
struct AInputEvent;
typedef struct AInputEvent AInputEvent;

/*
 * Input event types.
 */
enum {
    /* Indicates that the input event is a key event. */
    AINPUT_EVENT_TYPE_KEY = 1,

    /* Indicates that the input event is a motion event. */
    AINPUT_EVENT_TYPE_MOTION = 2
};

/*
 * Key event actions.
 */
enum {
    /* The key has been pressed down. */
    AKEY_EVENT_ACTION_DOWN = 0,

    /* The key has been released. */
    AKEY_EVENT_ACTION_UP = 1,

    /* Multiple duplicate key events have occurred in a row, or a complex string is
     * being delivered.  The repeat_count property of the key event contains the number
     * of times the given key code should be executed.
     */
    AKEY_EVENT_ACTION_MULTIPLE = 2
};

/*
 * Key event flags.
 */
enum {
    /* This mask is set if the device woke because of this key event. */
    AKEY_EVENT_FLAG_WOKE_HERE = 0x1,

    /* This mask is set if the key event was generated by a software keyboard. */
    AKEY_EVENT_FLAG_SOFT_KEYBOARD = 0x2,

    /* This mask is set if we don't want the key event to cause us to leave touch mode. */
    AKEY_EVENT_FLAG_KEEP_TOUCH_MODE = 0x4,

    /* This mask is set if an event was known to come from a trusted part
     * of the system.  That is, the event is known to come from the user,
     * and could not have been spoofed by a third party component. */
    AKEY_EVENT_FLAG_FROM_SYSTEM = 0x8,

    /* This mask is used for compatibility, to identify enter keys that are
     * coming from an IME whose enter key has been auto-labelled "next" or
     * "done".  This allows TextView to dispatch these as normal enter keys
     * for old applications, but still do the appropriate action when
     * receiving them. */
    AKEY_EVENT_FLAG_EDITOR_ACTION = 0x10,

    /* When associated with up key events, this indicates that the key press
     * has been canceled.  Typically this is used with virtual touch screen
     * keys, where the user can slide from the virtual key area on to the
     * display: in that case, the application will receive a canceled up
     * event and should not perform the action normally associated with the
     * key.  Note that for this to work, the application can not perform an
     * action for a key until it receives an up or the long press timeout has
     * expired. */
    AKEY_EVENT_FLAG_CANCELED = 0x20,

    /* This key event was generated by a virtual (on-screen) hard key area.
     * Typically this is an area of the touchscreen, outside of the regular
     * display, dedicated to "hardware" buttons. */
    AKEY_EVENT_FLAG_VIRTUAL_HARD_KEY = 0x40,

    /* This flag is set for the first key repeat that occurs after the
     * long press timeout. */
    AKEY_EVENT_FLAG_LONG_PRESS = 0x80,

    /* Set when a key event has AKEY_EVENT_FLAG_CANCELED set because a long
     * press action was executed while it was down. */
    AKEY_EVENT_FLAG_CANCELED_LONG_PRESS = 0x100,

    /* Set for AKEY_EVENT_ACTION_UP when this event's key code is still being
     * tracked from its initial down.  That is, somebody requested that tracking
     * started on the key down and a long press has not caused
     * the tracking to be canceled. */
    AKEY_EVENT_FLAG_TRACKING = 0x200
};

/*
 * Motion event actions.
 */

/* Bit shift for the action bits holding the pointer index as
 * defined by AMOTION_EVENT_ACTION_POINTER_INDEX_MASK.
 */
#define AMOTION_EVENT_ACTION_POINTER_INDEX_SHIFT 8

enum {
    /* Bit mask of the parts of the action code that are the action itself.
     */
    AMOTION_EVENT_ACTION_MASK = 0xff,

    /* Bits in the action code that represent a pointer index, used with
     * AMOTION_EVENT_ACTION_POINTER_DOWN and AMOTION_EVENT_ACTION_POINTER_UP.  Shifting
     * down by AMOTION_EVENT_ACTION_POINTER_INDEX_SHIFT provides the actual pointer
     * index where the data for the pointer going up or down can be found.
     */
    AMOTION_EVENT_ACTION_POINTER_INDEX_MASK  = 0xff00,

    /* A pressed gesture has started, the motion contains the initial starting location.
     */
    AMOTION_EVENT_ACTION_DOWN = 0,

    /* A pressed gesture has finished, the motion contains the final release location
     * as well as any intermediate points since the last down or move event.
     */
    AMOTION_EVENT_ACTION_UP = 1,

    /* A change has happened during a press gesture (between AMOTION_EVENT_ACTION_DOWN and
     * AMOTION_EVENT_ACTION_UP).  The motion contains the most recent point, as well as
     * any intermediate points since the last down or move event.
     */
    AMOTION_EVENT_ACTION_MOVE = 2,

    /* The current gesture has been aborted.
     * You will not receive any more points in it.  You should treat this as
     * an up event, but not perform any action that you normally would.
     */
    AMOTION_EVENT_ACTION_CANCEL = 3,

    /* A movement has happened outside of the normal bounds of the UI element.
     * This does not provide a full gesture, but only the initial location of the movement/touch.
     */
    AMOTION_EVENT_ACTION_OUTSIDE = 4,

    /* A non-primary pointer has gone down.
     * The bits in AMOTION_EVENT_ACTION_POINTER_INDEX_MASK indicate which pointer changed.
     */
    AMOTION_EVENT_ACTION_POINTER_DOWN = 5,

    /* A non-primary pointer has gone up.
     * The bits in AMOTION_EVENT_ACTION_POINTER_INDEX_MASK indicate which pointer changed.
     */
    AMOTION_EVENT_ACTION_POINTER_UP = 6
};

/*
 * Motion event edge touch flags.
 */
enum {
    /* No edges intersected */
    AMOTION_EVENT_EDGE_FLAG_NONE = 0,

    /* Flag indicating the motion event intersected the top edge of the screen. */
    AMOTION_EVENT_EDGE_FLAG_TOP = 0x01,

    /* Flag indicating the motion event intersected the bottom edge of the screen. */
    AMOTION_EVENT_EDGE_FLAG_BOTTOM = 0x02,

    /* Flag indicating the motion event intersected the left edge of the screen. */
    AMOTION_EVENT_EDGE_FLAG_LEFT = 0x04,

    /* Flag indicating the motion event intersected the right edge of the screen. */
    AMOTION_EVENT_EDGE_FLAG_RIGHT = 0x08
};

/*
 * Input sources.
 *
 * The appropriate interpretation for an input event depends on its source.
 * Refer to the documentation on android.view.InputDevice for more details about input sources
 * and their correct interpretation.
 */
enum {
    AINPUT_SOURCE_CLASS_MASK = 0x000000ff,

    AINPUT_SOURCE_CLASS_BUTTON = 0x00000001,
    AINPUT_SOURCE_CLASS_POINTER = 0x00000002,
    AINPUT_SOURCE_CLASS_NAVIGATION = 0x00000004,
    AINPUT_SOURCE_CLASS_POSITION = 0x00000008,
    AINPUT_SOURCE_CLASS_JOYSTICK = 0x00000010,
};

enum {
    AINPUT_SOURCE_UNKNOWN = 0x00000000,

    AINPUT_SOURCE_KEYBOARD = 0x00000100 | AINPUT_SOURCE_CLASS_BUTTON,
    AINPUT_SOURCE_DPAD = 0x00000200 | AINPUT_SOURCE_CLASS_BUTTON,
    AINPUT_SOURCE_GAMEPAD = 0x00000400 | AINPUT_SOURCE_CLASS_BUTTON,
    AINPUT_SOURCE_TOUCHSCREEN = 0x00001000 | AINPUT_SOURCE_CLASS_POINTER,
    AINPUT_SOURCE_MOUSE = 0x00002000 | AINPUT_SOURCE_CLASS_POINTER,
    AINPUT_SOURCE_TRACKBALL = 0x00010000 | AINPUT_SOURCE_CLASS_NAVIGATION,
    AINPUT_SOURCE_TOUCHPAD = 0x00100000 | AINPUT_SOURCE_CLASS_POSITION,
    AINPUT_SOURCE_JOYSTICK_LEFT = 0x01000000 | AINPUT_SOURCE_CLASS_JOYSTICK,
    AINPUT_SOURCE_JOYSTICK_RIGHT = 0x02000000 | AINPUT_SOURCE_CLASS_JOYSTICK,
};

/*
 * Input event accessors.
 *
 * Note that most functions can only be used on input events that are of a given type.
 * Calling these functions on input events of other types will yield undefined behavior.
 */

/*** Accessors for all input events. ***/

/* Get the input event type. */
int32_t AInputEvent_getType(const AInputEvent* event);

/* Get the id for the device that an input event came from.
 *
 * Input events can be generated by multiple different input devices.
 * Use the input device id to obtain information about the input
 * device that was responsible for generating a particular event.
 *
 * An input device id of 0 indicates that the event didn't come from a physical device;
 * other numbers are arbitrary and you shouldn't depend on the values.
 * Use the provided input device query API to obtain information about input devices.
 */
int32_t AInputEvent_getDeviceId(const AInputEvent* event);

/* Get the input event source. */
int32_t AInputEvent_getSource(const AInputEvent* event);

/*** Accessors for key events only. ***/

/* Get the key event action. */
int32_t AKeyEvent_getAction(const AInputEvent* key_event);

/* Get the key event flags. */
int32_t AKeyEvent_getFlags(const AInputEvent* key_event);

/* Get the key code of the key event.
 * This is the physical key that was pressed, not the Unicode character. */
int32_t AKeyEvent_getKeyCode(const AInputEvent* key_event);

/* Get the hardware key id of this key event.
 * These values are not reliable and vary from device to device. */
int32_t AKeyEvent_getScanCode(const AInputEvent* key_event);

/* Get the meta key state. */
int32_t AKeyEvent_getMetaState(const AInputEvent* key_event);

/* Get the repeat count of the event.
 * For both key up an key down events, this is the number of times the key has
 * repeated with the first down starting at 0 and counting up from there.  For
 * multiple key events, this is the number of down/up pairs that have occurred. */
int32_t AKeyEvent_getRepeatCount(const AInputEvent* key_event);

/* Get the time of the most recent key down event, in the
 * java.lang.System.nanoTime() time base.  If this is a down event,
 * this will be the same as eventTime.
 * Note that when chording keys, this value is the down time of the most recently
 * pressed key, which may not be the same physical key of this event. */
int64_t AKeyEvent_getDownTime(const AInputEvent* key_event);

/* Get the time this event occurred, in the
 * java.lang.System.nanoTime() time base. */
int64_t AKeyEvent_getEventTime(const AInputEvent* key_event);

/*** Accessors for motion events only. ***/

/* Get the combined motion event action code and pointer index. */
int32_t AMotionEvent_getAction(const AInputEvent* motion_event);

/* Get the state of any meta / modifier keys that were in effect when the
 * event was generated. */
int32_t AMotionEvent_getMetaState(const AInputEvent* motion_event);

/* Get a bitfield indicating which edges, if any, were touched by this motion event.
 * For touch events, clients can use this to determine if the user's finger was
 * touching the edge of the display. */
int32_t AMotionEvent_getEdgeFlags(const AInputEvent* motion_event);

/* Get the time when the user originally pressed down to start a stream of
 * position events, in the java.lang.System.nanoTime() time base. */
int64_t AMotionEvent_getDownTime(const AInputEvent* motion_event);

/* Get the time when this specific event was generated,
 * in the java.lang.System.nanoTime() time base. */
int64_t AMotionEvent_getEventTime(const AInputEvent* motion_event);

/* Get the X coordinate offset.
 * For touch events on the screen, this is the delta that was added to the raw
 * screen coordinates to adjust for the absolute position of the containing windows
 * and views. */
float AMotionEvent_getXOffset(const AInputEvent* motion_event);

/* Get the precision of the Y coordinates being reported.
 * For touch events on the screen, this is the delta that was added to the raw
 * screen coordinates to adjust for the absolute position of the containing windows
 * and views. */
float AMotionEvent_getYOffset(const AInputEvent* motion_event);

/* Get the precision of the X coordinates being reported.
 * You can multiply this number with an X coordinate sample to find the
 * actual hardware value of the X coordinate. */
float AMotionEvent_getXPrecision(const AInputEvent* motion_event);

/* Get the precision of the Y coordinates being reported.
 * You can multiply this number with a Y coordinate sample to find the
 * actual hardware value of the Y coordinate. */
float AMotionEvent_getYPrecision(const AInputEvent* motion_event);

/* Get the number of pointers of data contained in this event.
 * Always >= 1. */
size_t AMotionEvent_getPointerCount(const AInputEvent* motion_event);

/* Get the pointer identifier associated with a particular pointer
 * data index is this event.  The identifier tells you the actual pointer
 * number associated with the data, accounting for individual pointers
 * going up and down since the start of the current gesture. */
int32_t AMotionEvent_getPointerId(const AInputEvent* motion_event, size_t pointer_index);

/* Get the original raw X coordinate of this event.
 * For touch events on the screen, this is the original location of the event
 * on the screen, before it had been adjusted for the containing window
 * and views. */
float AMotionEvent_getRawX(const AInputEvent* motion_event, size_t pointer_index);

/* Get the original raw X coordinate of this event.
 * For touch events on the screen, this is the original location of the event
 * on the screen, before it had been adjusted for the containing window
 * and views. */
float AMotionEvent_getRawY(const AInputEvent* motion_event, size_t pointer_index);

/* Get the current X coordinate of this event for the given pointer index.
 * Whole numbers are pixels; the value may have a fraction for input devices
 * that are sub-pixel precise. */
float AMotionEvent_getX(const AInputEvent* motion_event, size_t pointer_index);

/* Get the current Y coordinate of this event for the given pointer index.
 * Whole numbers are pixels; the value may have a fraction for input devices
 * that are sub-pixel precise. */
float AMotionEvent_getY(const AInputEvent* motion_event, size_t pointer_index);

/* Get the current pressure of this event for the given pointer index.
 * The pressure generally ranges from 0 (no pressure at all) to 1 (normal pressure),
 * however values higher than 1 may be generated depending on the calibration of
 * the input device. */
float AMotionEvent_getPressure(const AInputEvent* motion_event, size_t pointer_index);

/* Get the current scaled value of the approximate size for the given pointer index.
 * This represents some approximation of the area of the screen being
 * pressed; the actual value in pixels corresponding to the
 * touch is normalized with the device specific range of values
 * and scaled to a value between 0 and 1.  The value of size can be used to
 * determine fat touch events. */
float AMotionEvent_getSize(const AInputEvent* motion_event, size_t pointer_index);

/* Get the current length of the major axis of an ellipse that describes the touch area
 * at the point of contact for the given pointer index. */
float AMotionEvent_getTouchMajor(const AInputEvent* motion_event, size_t pointer_index);

/* Get the current length of the minor axis of an ellipse that describes the touch area
 * at the point of contact for the given pointer index. */
float AMotionEvent_getTouchMinor(const AInputEvent* motion_event, size_t pointer_index);

/* Get the current length of the major axis of an ellipse that describes the size
 * of the approaching tool for the given pointer index.
 * The tool area represents the estimated size of the finger or pen that is
 * touching the device independent of its actual touch area at the point of contact. */
float AMotionEvent_getToolMajor(const AInputEvent* motion_event, size_t pointer_index);

/* Get the current length of the minor axis of an ellipse that describes the size
 * of the approaching tool for the given pointer index.
 * The tool area represents the estimated size of the finger or pen that is
 * touching the device independent of its actual touch area at the point of contact. */
float AMotionEvent_getToolMinor(const AInputEvent* motion_event, size_t pointer_index);

/* Get the current orientation of the touch area and tool area in radians clockwise from
 * vertical for the given pointer index.
 * An angle of 0 degrees indicates that the major axis of contact is oriented
 * upwards, is perfectly circular or is of unknown orientation.  A positive angle
 * indicates that the major axis of contact is oriented to the right.  A negative angle
 * indicates that the major axis of contact is oriented to the left.
 * The full range is from -PI/4 radians (finger pointing fully left) to PI/4 radians
 * (finger pointing fully right). */
float AMotionEvent_getOrientation(const AInputEvent* motion_event, size_t pointer_index);

/* Get the number of historical points in this event.  These are movements that
 * have occurred between this event and the previous event.  This only applies
 * to AMOTION_EVENT_ACTION_MOVE events -- all other actions will have a size of 0.
 * Historical samples are indexed from oldest to newest. */
size_t AMotionEvent_getHistorySize(const AInputEvent* motion_event);

/* Get the time that a historical movement occurred between this event and
 * the previous event, in the java.lang.System.nanoTime() time base. */
int64_t AMotionEvent_getHistoricalEventTime(AInputEvent* motion_event,
        size_t history_index);

/* Get the historical raw X coordinate of this event for the given pointer index that
 * occurred between this event and the previous motion event.
 * For touch events on the screen, this is the original location of the event
 * on the screen, before it had been adjusted for the containing window
 * and views.
 * Whole numbers are pixels; the value may have a fraction for input devices
 * that are sub-pixel precise. */
float AMotionEvent_getHistoricalRawX(const AInputEvent* motion_event, size_t pointer_index);

/* Get the historical raw Y coordinate of this event for the given pointer index that
 * occurred between this event and the previous motion event.
 * For touch events on the screen, this is the original location of the event
 * on the screen, before it had been adjusted for the containing window
 * and views.
 * Whole numbers are pixels; the value may have a fraction for input devices
 * that are sub-pixel precise. */
float AMotionEvent_getHistoricalRawY(const AInputEvent* motion_event, size_t pointer_index);

/* Get the historical X coordinate of this event for the given pointer index that
 * occurred between this event and the previous motion event.
 * Whole numbers are pixels; the value may have a fraction for input devices
 * that are sub-pixel precise. */
float AMotionEvent_getHistoricalX(AInputEvent* motion_event, size_t pointer_index,
        size_t history_index);

/* Get the historical Y coordinate of this event for the given pointer index that
 * occurred between this event and the previous motion event.
 * Whole numbers are pixels; the value may have a fraction for input devices
 * that are sub-pixel precise. */
float AMotionEvent_getHistoricalY(AInputEvent* motion_event, size_t pointer_index,
        size_t history_index);

/* Get the historical pressure of this event for the given pointer index that
 * occurred between this event and the previous motion event.
 * The pressure generally ranges from 0 (no pressure at all) to 1 (normal pressure),
 * however values higher than 1 may be generated depending on the calibration of
 * the input device. */
float AMotionEvent_getHistoricalPressure(AInputEvent* motion_event, size_t pointer_index,
        size_t history_index);

/* Get the current scaled value of the approximate size for the given pointer index that
 * occurred between this event and the previous motion event.
 * This represents some approximation of the area of the screen being
 * pressed; the actual value in pixels corresponding to the
 * touch is normalized with the device specific range of values
 * and scaled to a value between 0 and 1.  The value of size can be used to
 * determine fat touch events. */
float AMotionEvent_getHistoricalSize(AInputEvent* motion_event, size_t pointer_index,
        size_t history_index);

/* Get the historical length of the major axis of an ellipse that describes the touch area
 * at the point of contact for the given pointer index that
 * occurred between this event and the previous motion event. */
float AMotionEvent_getHistoricalTouchMajor(const AInputEvent* motion_event, size_t pointer_index,
        size_t history_index);

/* Get the historical length of the minor axis of an ellipse that describes the touch area
 * at the point of contact for the given pointer index that
 * occurred between this event and the previous motion event. */
float AMotionEvent_getHistoricalTouchMinor(const AInputEvent* motion_event, size_t pointer_index,
        size_t history_index);

/* Get the historical length of the major axis of an ellipse that describes the size
 * of the approaching tool for the given pointer index that
 * occurred between this event and the previous motion event.
 * The tool area represents the estimated size of the finger or pen that is
 * touching the device independent of its actual touch area at the point of contact. */
float AMotionEvent_getHistoricalToolMajor(const AInputEvent* motion_event, size_t pointer_index,
        size_t history_index);

/* Get the historical length of the minor axis of an ellipse that describes the size
 * of the approaching tool for the given pointer index that
 * occurred between this event and the previous motion event.
 * The tool area represents the estimated size of the finger or pen that is
 * touching the device independent of its actual touch area at the point of contact. */
float AMotionEvent_getHistoricalToolMinor(const AInputEvent* motion_event, size_t pointer_index,
        size_t history_index);

/* Get the historical orientation of the touch area and tool area in radians clockwise from
 * vertical for the given pointer index that
 * occurred between this event and the previous motion event.
 * An angle of 0 degrees indicates that the major axis of contact is oriented
 * upwards, is perfectly circular or is of unknown orientation.  A positive angle
 * indicates that the major axis of contact is oriented to the right.  A negative angle
 * indicates that the major axis of contact is oriented to the left.
 * The full range is from -PI/4 radians (finger pointing fully left) to PI/4 radians
 * (finger pointing fully right). */
float AMotionEvent_getHistoricalOrientation(const AInputEvent* motion_event, size_t pointer_index,
        size_t history_index);


/*
 * Input queue
 *
 * An input queue is the facility through which you retrieve input
 * events.
 */
struct AInputQueue;
typedef struct AInputQueue AInputQueue;

/*
 * Add this input queue to a looper for processing.  See
 * ALooper_addFd() for information on the callback and data params.
 */
void AInputQueue_attachLooper(AInputQueue* queue, ALooper* looper,
        ALooper_callbackFunc* callback, void* data);

/*
 * Remove the input queue from the looper it is currently attached to.
 */
void AInputQueue_detachLooper(AInputQueue* queue);

/*
 * Returns true if there are one or more events available in the
 * input queue.  Returns 1 if the queue has events; 0 if
 * it does not have events; and a negative value if there is an error.
 */
int AInputQueue_hasEvents(AInputQueue* queue);

/*
 * Returns the next available event from the queue.  Returns a negative
 * value if no events are available or an error has occurred.
 */
int32_t AInputQueue_getEvent(AInputQueue* queue, AInputEvent** outEvent);

/*
 * Report that dispatching has finished with the given event.
 * This must be called after receiving an event with AInputQueue_get_event().
 */
void AInputQueue_finishEvent(AInputQueue* queue, AInputEvent* event, int handled);

#ifdef __cplusplus
}
#endif

#endif // _ANDROID_INPUT_H