/*
* Copyright (C) 2011 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.support.v4.view;
import android.view.MotionEvent;
/**
* Helper for accessing features in {@link MotionEvent} introduced
* after API level 4 in a backwards compatible fashion.
*/
public class MotionEventCompat {
/**
* Interface for the full API.
*/
interface MotionEventVersionImpl {
public int findPointerIndex(MotionEvent event, int pointerId);
public int getPointerId(MotionEvent event, int pointerIndex);
public float getX(MotionEvent event, int pointerIndex);
public float getY(MotionEvent event, int pointerIndex);
public int getPointerCount(MotionEvent event);
}
/**
* Interface implementation that doesn't use anything about v4 APIs.
*/
static class BaseMotionEventVersionImpl implements MotionEventVersionImpl {
@Override
public int findPointerIndex(MotionEvent event, int pointerId) {
if (pointerId == 0) {
// id 0 == index 0 and vice versa.
return 0;
}
return -1;
}
@Override
public int getPointerId(MotionEvent event, int pointerIndex) {
if (pointerIndex == 0) {
// index 0 == id 0 and vice versa.
return 0;
}
throw new IndexOutOfBoundsException("Pre-Eclair does not support multiple pointers");
}
@Override
public float getX(MotionEvent event, int pointerIndex) {
if (pointerIndex == 0) {
return event.getX();
}
throw new IndexOutOfBoundsException("Pre-Eclair does not support multiple pointers");
}
@Override
public float getY(MotionEvent event, int pointerIndex) {
if (pointerIndex == 0) {
return event.getY();
}
throw new IndexOutOfBoundsException("Pre-Eclair does not support multiple pointers");
}
@Override
public int getPointerCount(MotionEvent event) {
return 1;
}
}
/**
* Interface implementation for devices with at least v11 APIs.
*/
static class EclairMotionEventVersionImpl implements MotionEventVersionImpl {
@Override
public int findPointerIndex(MotionEvent event, int pointerId) {
return MotionEventCompatEclair.findPointerIndex(event, pointerId);
}
@Override
public int getPointerId(MotionEvent event, int pointerIndex) {
return MotionEventCompatEclair.getPointerId(event, pointerIndex);
}
@Override
public float getX(MotionEvent event, int pointerIndex) {
return MotionEventCompatEclair.getX(event, pointerIndex);
}
@Override
public float getY(MotionEvent event, int pointerIndex) {
return MotionEventCompatEclair.getY(event, pointerIndex);
}
@Override
public int getPointerCount(MotionEvent event) {
return MotionEventCompatEclair.getPointerCount(event);
}
}
/**
* Select the correct implementation to use for the current platform.
*/
static final MotionEventVersionImpl IMPL;
static {
if (android.os.Build.VERSION.SDK_INT >= 5) {
IMPL = new EclairMotionEventVersionImpl();
} else {
IMPL = new BaseMotionEventVersionImpl();
}
}
// -------------------------------------------------------------------
/**
* Synonym for {@link MotionEvent#ACTION_MASK}.
*/
public static final int ACTION_MASK = 0xff;
/**
* Synonym for {@link MotionEvent#ACTION_POINTER_DOWN}.
*/
public static final int ACTION_POINTER_DOWN = 5;
/**
* Synonym for {@link MotionEvent#ACTION_POINTER_UP}.
*/
public static final int ACTION_POINTER_UP = 6;
/**
* Synonym for {@link MotionEvent#ACTION_HOVER_MOVE}.
*/
public static final int ACTION_HOVER_MOVE = 7;
/**
* Synonym for {@link MotionEvent#ACTION_SCROLL}.
*/
public static final int ACTION_SCROLL = 8;
/**
* Synonym for {@link MotionEvent#ACTION_POINTER_INDEX_MASK}.
*/
public static final int ACTION_POINTER_INDEX_MASK = 0xff00;
/**
* Synonym for {@link MotionEvent#ACTION_POINTER_INDEX_SHIFT}.
*/
public static final int ACTION_POINTER_INDEX_SHIFT = 8;
/**
* Constant for {@link #getActionMasked}: The pointer is not down but has entered the
* boundaries of a window or view.
* <p>
* This action is always delivered to the window or view under the pointer.
* </p><p>
* This action is not a touch event so it is delivered to
* {@link android.view.View#onGenericMotionEvent(MotionEvent)} rather than
* {@link android.view.View#onTouchEvent(MotionEvent)}.
* </p>
*/
public static final int ACTION_HOVER_ENTER = 9;
/**
* Constant for {@link #getActionMasked}: The pointer is not down but has exited the
* boundaries of a window or view.
* <p>
* This action is always delivered to the window or view that was previously under the pointer.
* </p><p>
* This action is not a touch event so it is delivered to
* {@link android.view.View#onGenericMotionEvent(MotionEvent)} rather than
* {@link android.view.View#onTouchEvent(MotionEvent)}.
* </p>
*/
public static final int ACTION_HOVER_EXIT = 10;
/**
* Call {@link MotionEvent#getAction}, returning only the {@link #ACTION_MASK}
* portion.
*/
public static int getActionMasked(MotionEvent event) {
return event.getAction() & ACTION_MASK;
}
/**
* Call {@link MotionEvent#getAction}, returning only the pointer index
* portion
*/
public static int getActionIndex(MotionEvent event) {
return (event.getAction() & ACTION_POINTER_INDEX_MASK)
>> ACTION_POINTER_INDEX_SHIFT;
}
/**
* Call {@link MotionEvent#findPointerIndex(int)}.
* If running on a pre-{@link android.os.Build.VERSION_CODES#ECLAIR} device,
* does nothing and returns -1.
*/
public static int findPointerIndex(MotionEvent event, int pointerId) {
return IMPL.findPointerIndex(event, pointerId);
}
/**
* Call {@link MotionEvent#getPointerId(int)}.
* If running on a pre-{@link android.os.Build.VERSION_CODES#ECLAIR} device,
* {@link IndexOutOfBoundsException} is thrown.
*/
public static int getPointerId(MotionEvent event, int pointerIndex) {
return IMPL.getPointerId(event, pointerIndex);
}
/**
* Call {@link MotionEvent#getX(int)}.
* If running on a pre-{@link android.os.Build.VERSION_CODES#ECLAIR} device,
* {@link IndexOutOfBoundsException} is thrown.
*/
public static float getX(MotionEvent event, int pointerIndex) {
return IMPL.getX(event, pointerIndex);
}
/**
* Call {@link MotionEvent#getY(int)}.
* If running on a pre-{@link android.os.Build.VERSION_CODES#ECLAIR} device,
* {@link IndexOutOfBoundsException} is thrown.
*/
public static float getY(MotionEvent event, int pointerIndex) {
return IMPL.getY(event, pointerIndex);
}
/**
* The number of pointers of data contained in this event. Always
* >= 1.
*/
public static int getPointerCount(MotionEvent event) {
return IMPL.getPointerCount(event);
}
}
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