https://source.android.com/ 
/*
 * 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.
 */

package android.view;

import android.os.Parcel;
import android.os.Parcelable;

import java.util.concurrent.atomic.AtomicInteger;


Common base class for input events.

/**
 * Common base class for input events.
 */
public abstract class InputEvent implements Parcelable {
    
@hide
/** @hide */
    protected static final int PARCEL_TOKEN_MOTION_EVENT = 1;
    
@hide
/** @hide */
    protected static final int PARCEL_TOKEN_KEY_EVENT = 2;

    // Next sequence number.
    private static final AtomicInteger mNextSeq = new AtomicInteger();

    
@hide
/** @hide */
    protected int mSeq;

    
@hide
/** @hide */
    protected boolean mRecycled;

    private static final boolean TRACK_RECYCLED_LOCATION = false;
    private RuntimeException mRecycledLocation;

    /*package*/ InputEvent() {
        mSeq = mNextSeq.getAndIncrement();
    }

    
Gets the id for the device that this event came from.  An id of
zero indicates that the event didn't come from a physical device
and maps to the default keymap.  The other numbers are arbitrary and
you shouldn't depend on the values.

See Also:
Returns:The device id.
/**
     * Gets the id for the device that this event came from.  An id of
     * zero indicates that the event didn't come from a physical device
     * and maps to the default keymap.  The other numbers are arbitrary and
     * you shouldn't depend on the values.
     * 
     * @return The device id.
     * @see InputDevice#getDevice
     */
    public abstract int getDeviceId();

    
Gets the device that this event came from.

Returns:The device, or null if unknown.
/**
     * Gets the device that this event came from.
     * 
     * @return The device, or null if unknown.
     */
    public final InputDevice getDevice() {
        return InputDevice.getDevice(getDeviceId());
    }

    
Gets the source of the event.

See Also:
Returns:The event source or InputDevice.SOURCE_UNKNOWN if unknown.
/**
     * Gets the source of the event.
     * 
     * @return The event source or {@link InputDevice#SOURCE_UNKNOWN} if unknown.
     * @see InputDevice#getSources
     */
    public abstract int getSource();

    
Modifies the source of the event.

Params:
  • source – The new source.
@hide
/**
     * Modifies the source of the event.
     *
     * @param source The new source.
     * @hide
     */
    public abstract void setSource(int source);

    
Determines whether the event is from the given source.

Params:
Returns:Whether the event is from the given source.
/**
     * Determines whether the event is from the given source.
     *
     * @param source The input source to check against. This can be a specific device type, such as
     * {@link InputDevice#SOURCE_TOUCH_NAVIGATION}, or a more generic device class, such as
     * {@link InputDevice#SOURCE_CLASS_POINTER}.
     * @return Whether the event is from the given source.
     */
    public boolean isFromSource(int source) {
        return (getSource() & source) == source;
    }

    
Copies the event.

Returns:A deep copy of the event.
@hide
/**
     * Copies the event.
     *
     * @return A deep copy of the event.
     * @hide
     */
    public abstract InputEvent copy();

    
Recycles the event. This method should only be used by the system since applications do not expect KeyEvent objects to be recycled, although MotionEvent objects are fine. See KeyEvent.recycle() for details. 
@hide
/**
     * Recycles the event.
     * This method should only be used by the system since applications do not
     * expect {@link KeyEvent} objects to be recycled, although {@link MotionEvent}
     * objects are fine.  See {@link KeyEvent#recycle()} for details.
     * @hide
     */
    public void recycle() {
        if (TRACK_RECYCLED_LOCATION) {
            if (mRecycledLocation != null) {
                throw new RuntimeException(toString() + " recycled twice!", mRecycledLocation);
            }
            mRecycledLocation = new RuntimeException("Last recycled here");
        } else {
            if (mRecycled) {
                throw new RuntimeException(toString() + " recycled twice!");
            }
            mRecycled = true;
        }
    }

    
Conditionally recycled the event if it is appropriate to do so after dispatching the event to an application. If the event is a MotionEvent then it is recycled. If the event is a KeyEvent then it is NOT recycled, because applications expect key events to be immutable so once the event has been dispatched to the application we can no longer recycle it. 
@hide
/**
     * Conditionally recycled the event if it is appropriate to do so after
     * dispatching the event to an application.
     *
     * If the event is a {@link MotionEvent} then it is recycled.
     *
     * If the event is a {@link KeyEvent} then it is NOT recycled, because applications
     * expect key events to be immutable so once the event has been dispatched to
     * the application we can no longer recycle it.
     * @hide
     */
    public void recycleIfNeededAfterDispatch() {
        recycle();
    }

    
Reinitializes the event on reuse (after recycling).

@hide
/**
     * Reinitializes the event on reuse (after recycling).
     * @hide
     */
    protected void prepareForReuse() {
        mRecycled = false;
        mRecycledLocation = null;
        mSeq = mNextSeq.getAndIncrement();
    }

    
Gets a private flag that indicates when the system has detected that this input event
may be inconsistent with respect to the sequence of previously delivered input events,
such as when a key up event is sent but the key was not down or when a pointer
move event is sent but the pointer is not down.

Returns:True if this event is tainted.
@hide
/**
     * Gets a private flag that indicates when the system has detected that this input event
     * may be inconsistent with respect to the sequence of previously delivered input events,
     * such as when a key up event is sent but the key was not down or when a pointer
     * move event is sent but the pointer is not down.
     *
     * @return True if this event is tainted.
     * @hide
     */
    public abstract boolean isTainted();

    
Sets a private flag that indicates when the system has detected that this input event
may be inconsistent with respect to the sequence of previously delivered input events,
such as when a key up event is sent but the key was not down or when a pointer
move event is sent but the pointer is not down.

Params:
  • tainted – True if this event is tainted.
@hide
/**
     * Sets a private flag that indicates when the system has detected that this input event
     * may be inconsistent with respect to the sequence of previously delivered input events,
     * such as when a key up event is sent but the key was not down or when a pointer
     * move event is sent but the pointer is not down.
     *
     * @param tainted True if this event is tainted.
     * @hide
     */
    public abstract void setTainted(boolean tainted);

    
Retrieve the time this event occurred, in the SystemClock.uptimeMillis time base. 
Returns:Returns the time this event occurred, in the SystemClock.uptimeMillis time base.
/**
     * Retrieve the time this event occurred,
     * in the {@link android.os.SystemClock#uptimeMillis} time base.
     *
     * @return Returns the time this event occurred,
     * in the {@link android.os.SystemClock#uptimeMillis} time base.
     */
    public abstract long getEventTime();

    
Retrieve the time this event occurred, in the SystemClock.uptimeMillis time base but with nanosecond (instead of millisecond) precision. 

The value is in nanosecond precision but it may not have nanosecond accuracy.



Returns:Returns the time this event occurred, in the SystemClock.uptimeMillis time base but with nanosecond (instead of millisecond) precision.
@hide
/**
     * Retrieve the time this event occurred,
     * in the {@link android.os.SystemClock#uptimeMillis} time base but with
     * nanosecond (instead of millisecond) precision.
     * <p>
     * The value is in nanosecond precision but it may not have nanosecond accuracy.
     * </p>
     *
     * @return Returns the time this event occurred,
     * in the {@link android.os.SystemClock#uptimeMillis} time base but with
     * nanosecond (instead of millisecond) precision.
     *
     * @hide
     */
    public abstract long getEventTimeNano();

    
Marks the input event as being canceled.

@hide
/**
     * Marks the input event as being canceled.
     *
     * @hide
     */
    public abstract void cancel();

    
Gets the unique sequence number of this event.
Every input event that is created or received by a process has a
unique sequence number.  Moreover, a new sequence number is obtained
each time an event object is recycled.
Sequence numbers are only guaranteed to be locally unique within a process.
Sequence numbers are not preserved when events are parceled.

Returns:The unique sequence number of this event.
@hide
/**
     * Gets the unique sequence number of this event.
     * Every input event that is created or received by a process has a
     * unique sequence number.  Moreover, a new sequence number is obtained
     * each time an event object is recycled.
     *
     * Sequence numbers are only guaranteed to be locally unique within a process.
     * Sequence numbers are not preserved when events are parceled.
     *
     * @return The unique sequence number of this event.
     * @hide
     */
    public int getSequenceNumber() {
        return mSeq;
    }

    public int describeContents() {
        return 0;
    }

    public static final Parcelable.Creator<InputEvent> CREATOR
            = new Parcelable.Creator<InputEvent>() {
        public InputEvent createFromParcel(Parcel in) {
            int token = in.readInt();
            if (token == PARCEL_TOKEN_KEY_EVENT) {
                return KeyEvent.createFromParcelBody(in);
            } else if (token == PARCEL_TOKEN_MOTION_EVENT) {
                return MotionEvent.createFromParcelBody(in);
            } else {
                throw new IllegalStateException("Unexpected input event type token in parcel.");
            }
        }
        
        public InputEvent[] newArray(int size) {
            return new InputEvent[size];
        }
    };
}