Example usage for android.view VelocityTracker obtain

Introduction

In this page you can find the example usage for android.view VelocityTracker obtain.

Prototype

static public VelocityTracker obtain() 

Source Link

Document

Retrieve a new VelocityTracker object to watch the velocity of a motion.

Usage

From source file:au.com.glassechidna.velocityviewpager.VelocityViewPager.java

/**
 * Start a fake drag of the pager.//from ww w  . j  av a2 s.c o  m
 *
 * <p>A fake drag can be useful if you want to synchronize the motion of the ViewPager
 * with the touch scrolling of another view, while still letting the ViewPager
 * control the snapping motion and fling behavior. (e.g. parallax-scrolling tabs.)
 * Call {@link #fakeDragBy(float)} to simulate the actual drag motion. Call
 * {@link #endFakeDrag()} to complete the fake drag and fling as necessary.
 *
 * <p>During a fake drag the ViewPager will ignore all touch events. If a real drag
 * is already in progress, this method will return false.
 *
 * @return true if the fake drag began successfully, false if it could not be started.
 *
 * @see #fakeDragBy(float)
 * @see #endFakeDrag()
 */
public boolean beginFakeDrag() {
    if (mIsBeingDragged) {
        return false;
    }
    mFakeDragging = true;
    setScrollState(SCROLL_STATE_DRAGGING);
    mInitialMotionX = mLastMotionX = 0;
    if (mVelocityTracker == null) {
        mVelocityTracker = VelocityTracker.obtain();
    } else {
        mVelocityTracker.clear();
    }
    final long time = SystemClock.uptimeMillis();
    final MotionEvent ev = MotionEvent.obtain(time, time, MotionEvent.ACTION_DOWN, 0, 0, 0);
    mVelocityTracker.addMovement(ev);
    ev.recycle();
    mFakeDragBeginTime = time;
    return true;
}

---

From source file:com.goftagram.telegram.messenger.support.widget.RecyclerView.java

@Override
public boolean onTouchEvent(MotionEvent e) {
    if (mLayoutFrozen || mIgnoreMotionEventTillDown) {
        return false;
    }//from  w  w  w  .ja v  a2  s . co  m
    if (dispatchOnItemTouch(e)) {
        cancelTouch();
        return true;
    }

    if (mLayout == null) {
        return false;
    }

    final boolean canScrollHorizontally = mLayout.canScrollHorizontally();
    final boolean canScrollVertically = mLayout.canScrollVertically();

    if (mVelocityTracker == null) {
        mVelocityTracker = VelocityTracker.obtain();
    }
    boolean eventAddedToVelocityTracker = false;

    final MotionEvent vtev = MotionEvent.obtain(e);
    final int action = MotionEventCompat.getActionMasked(e);
    final int actionIndex = MotionEventCompat.getActionIndex(e);

    if (action == MotionEvent.ACTION_DOWN) {
        mNestedOffsets[0] = mNestedOffsets[1] = 0;
    }
    vtev.offsetLocation(mNestedOffsets[0], mNestedOffsets[1]);

    switch (action) {
    case MotionEvent.ACTION_DOWN: {
        mScrollPointerId = MotionEventCompat.getPointerId(e, 0);
        mInitialTouchX = mLastTouchX = (int) (e.getX() + 0.5f);
        mInitialTouchY = mLastTouchY = (int) (e.getY() + 0.5f);

        int nestedScrollAxis = ViewCompat.SCROLL_AXIS_NONE;
        if (canScrollHorizontally) {
            nestedScrollAxis |= ViewCompat.SCROLL_AXIS_HORIZONTAL;
        }
        if (canScrollVertically) {
            nestedScrollAxis |= ViewCompat.SCROLL_AXIS_VERTICAL;
        }
        startNestedScroll(nestedScrollAxis);
    }
        break;

    case MotionEventCompat.ACTION_POINTER_DOWN: {
        mScrollPointerId = MotionEventCompat.getPointerId(e, actionIndex);
        mInitialTouchX = mLastTouchX = (int) (MotionEventCompat.getX(e, actionIndex) + 0.5f);
        mInitialTouchY = mLastTouchY = (int) (MotionEventCompat.getY(e, actionIndex) + 0.5f);
    }
        break;

    case MotionEvent.ACTION_MOVE: {
        final int index = MotionEventCompat.findPointerIndex(e, mScrollPointerId);
        if (index < 0) {
            Log.e(TAG, "Error processing scroll; pointer index for id " + mScrollPointerId
                    + " not found. Did any MotionEvents get skipped?");
            return false;
        }

        final int x = (int) (MotionEventCompat.getX(e, index) + 0.5f);
        final int y = (int) (MotionEventCompat.getY(e, index) + 0.5f);
        int dx = mLastTouchX - x;
        int dy = mLastTouchY - y;

        if (dispatchNestedPreScroll(dx, dy, mScrollConsumed, mScrollOffset)) {
            dx -= mScrollConsumed[0];
            dy -= mScrollConsumed[1];
            vtev.offsetLocation(mScrollOffset[0], mScrollOffset[1]);
            // Updated the nested offsets
            mNestedOffsets[0] += mScrollOffset[0];
            mNestedOffsets[1] += mScrollOffset[1];
        }

        if (mScrollState != SCROLL_STATE_DRAGGING) {
            boolean startScroll = false;
            if (canScrollHorizontally && Math.abs(dx) > mTouchSlop) {
                if (dx > 0) {
                    dx -= mTouchSlop;
                } else {
                    dx += mTouchSlop;
                }
                startScroll = true;
            }
            if (canScrollVertically && Math.abs(dy) > mTouchSlop) {
                if (dy > 0) {
                    dy -= mTouchSlop;
                } else {
                    dy += mTouchSlop;
                }
                startScroll = true;
            }
            if (startScroll) {
                final ViewParent parent = getParent();
                if (parent != null) {
                    parent.requestDisallowInterceptTouchEvent(true);
                }
                setScrollState(SCROLL_STATE_DRAGGING);
            }
        }

        if (mScrollState == SCROLL_STATE_DRAGGING) {
            mLastTouchX = x - mScrollOffset[0];
            mLastTouchY = y - mScrollOffset[1];

            if (scrollByInternal(canScrollHorizontally ? dx : 0, canScrollVertically ? dy : 0, vtev)) {
                getParent().requestDisallowInterceptTouchEvent(true);
            }
        }
    }
        break;

    case MotionEventCompat.ACTION_POINTER_UP: {
        onPointerUp(e);
    }
        break;

    case MotionEvent.ACTION_UP: {
        mVelocityTracker.addMovement(vtev);
        eventAddedToVelocityTracker = true;
        mVelocityTracker.computeCurrentVelocity(1000, mMaxFlingVelocity);
        final float xvel = canScrollHorizontally
                ? -VelocityTrackerCompat.getXVelocity(mVelocityTracker, mScrollPointerId)
                : 0;
        final float yvel = canScrollVertically
                ? -VelocityTrackerCompat.getYVelocity(mVelocityTracker, mScrollPointerId)
                : 0;
        if (!((xvel != 0 || yvel != 0) && fling((int) xvel, (int) yvel))) {
            setScrollState(SCROLL_STATE_IDLE);
        }
        resetTouch();
    }
        break;

    case MotionEvent.ACTION_CANCEL: {
        cancelTouch();
    }
        break;
    }

    if (!eventAddedToVelocityTracker) {
        mVelocityTracker.addMovement(vtev);
    }
    vtev.recycle();

    return true;
}

---

From source file:com.tjych.swip.vertical.DirectionalViewPager.java

/**
 * Start a fake drag of the pager.//from  ww  w .jav  a2s .c  o m
 *
 * <p>A fake drag can be useful if you want to synchronize the motion of the ViewPager
 * with the touch scrolling of another view, while still letting the ViewPager
 * control the snapping motion and fling behavior. (e.g. parallax-scrolling tabs.)
 * Call {@link #fakeDragBy(float)} to simulate the actual drag motion. Call
 * {@link #endFakeDrag()} to complete the fake drag and fling as necessary.
 *
 * <p>During a fake drag the ViewPager will ignore all touch events. If a real drag
 * is already in progress, this method will return false.
 *
 * @return true if the fake drag began successfully, false if it could not be started.
 *
 * @see #fakeDragBy(float)
 * @see #endFakeDrag()
 */
public boolean beginFakeDrag() {
    if (mIsBeingDragged) {
        return false;
    }
    mFakeDragging = true;
    setScrollState(SCROLL_STATE_DRAGGING);
    mInitialMotionX = mLastMotionX = 0;
    mInitialMotionY = mLastMotionY = 0;
    if (mVelocityTracker == null) {
        mVelocityTracker = VelocityTracker.obtain();
    } else {
        mVelocityTracker.clear();
    }
    final long time = SystemClock.uptimeMillis();
    final MotionEvent ev = MotionEvent.obtain(time, time, MotionEvent.ACTION_DOWN, 0, 0, 0);
    mVelocityTracker.addMovement(ev);
    ev.recycle();
    mFakeDragBeginTime = time;
    return true;
}

---

From source file:android.support.v71.widget.RecyclerView.java

@Override
public boolean onInterceptTouchEvent(MotionEvent e) {
    if (mLayoutFrozen) {
        // When layout is frozen,  RV does not intercept the motion event.
        // A child view e.g. a button may still get the click.
        return false;
    }//w  w  w. j a v  a  2 s  .  c om
    if (dispatchOnItemTouchIntercept(e)) {
        cancelTouch();
        return true;
    }

    if (mLayout == null) {
        return false;
    }

    final boolean canScrollHorizontally = mLayout.canScrollHorizontally();
    final boolean canScrollVertically = mLayout.canScrollVertically();

    if (mVelocityTracker == null) {
        mVelocityTracker = VelocityTracker.obtain();
    }
    mVelocityTracker.addMovement(e);

    final int action = MotionEventCompat.getActionMasked(e);
    final int actionIndex = MotionEventCompat.getActionIndex(e);

    switch (action) {
    case MotionEvent.ACTION_DOWN:
        if (mIgnoreMotionEventTillDown) {
            mIgnoreMotionEventTillDown = false;
        }
        mScrollPointerId = MotionEventCompat.getPointerId(e, 0);
        mInitialTouchX = mLastTouchX = (int) (e.getX() + 0.5f);
        mInitialTouchY = mLastTouchY = (int) (e.getY() + 0.5f);

        if (mScrollState == SCROLL_STATE_SETTLING) {
            getParent().requestDisallowInterceptTouchEvent(true);
            setScrollState(SCROLL_STATE_DRAGGING);
        }

        // Clear the nested offsets
        mNestedOffsets[0] = mNestedOffsets[1] = 0;

        int nestedScrollAxis = ViewCompat.SCROLL_AXIS_NONE;
        if (canScrollHorizontally) {
            nestedScrollAxis |= ViewCompat.SCROLL_AXIS_HORIZONTAL;
        }
        if (canScrollVertically) {
            nestedScrollAxis |= ViewCompat.SCROLL_AXIS_VERTICAL;
        }
        startNestedScroll(nestedScrollAxis);
        break;

    case MotionEventCompat.ACTION_POINTER_DOWN:
        mScrollPointerId = MotionEventCompat.getPointerId(e, actionIndex);
        mInitialTouchX = mLastTouchX = (int) (MotionEventCompat.getX(e, actionIndex) + 0.5f);
        mInitialTouchY = mLastTouchY = (int) (MotionEventCompat.getY(e, actionIndex) + 0.5f);
        break;

    case MotionEvent.ACTION_MOVE: {
        final int index = MotionEventCompat.findPointerIndex(e, mScrollPointerId);
        if (index < 0) {
            Log.e(TAG, "Error processing scroll; pointer index for id " + mScrollPointerId
                    + " not found. Did any MotionEvents get skipped?");
            return false;
        }

        final int x = (int) (MotionEventCompat.getX(e, index) + 0.5f);
        final int y = (int) (MotionEventCompat.getY(e, index) + 0.5f);
        if (mScrollState != SCROLL_STATE_DRAGGING) {
            final int dx = x - mInitialTouchX;
            final int dy = y - mInitialTouchY;
            boolean startScroll = false;
            if (canScrollHorizontally && Math.abs(dx) > mTouchSlop) {
                mLastTouchX = mInitialTouchX + mTouchSlop * (dx < 0 ? -1 : 1);
                startScroll = true;
            }
            if (canScrollVertically && Math.abs(dy) > mTouchSlop) {
                mLastTouchY = mInitialTouchY + mTouchSlop * (dy < 0 ? -1 : 1);
                startScroll = true;
            }
            if (startScroll) {
                setScrollState(SCROLL_STATE_DRAGGING);
            }
        }
    }
        break;

    case MotionEventCompat.ACTION_POINTER_UP: {
        onPointerUp(e);
    }
        break;

    case MotionEvent.ACTION_UP: {
        mVelocityTracker.clear();
        stopNestedScroll();
    }
        break;

    case MotionEvent.ACTION_CANCEL: {
        cancelTouch();
    }
    }
    return mScrollState == SCROLL_STATE_DRAGGING;
}

---

From source file:cn.androidy.materialdesignsample.ryanharterviewpager.ViewPager.java

/**
 * Start a fake drag of the pager.//from  w w  w. j a va2  s  .co  m
 *
 * <p>A fake drag can be useful if you want to synchronize the motion of the ViewPager
 * with the touch scrolling of another view, while still letting the ViewPager
 * control the snapping motion and fling behavior. (e.g. parallax-scrolling tabs.)
 * Call {@link #fakeDragBy(float)} to simulate the actual drag motion. Call
 * {@link #endFakeDrag()} to complete the fake drag and fling as necessary.
 *
 * <p>During a fake drag the ViewPager will ignore all touch events. If a real drag
 * is already in progress, this method will return false.
 *
 * @return true if the fake drag began successfully, false if it could not be started.
 *
 * @see #fakeDragBy(float)
 * @see #endFakeDrag()
 */
public boolean beginFakeDrag() {
    if (mIsBeingDragged) {
        return false;
    }
    mFakeDragging = true;
    setScrollState(SCROLL_STATE_DRAGGING);
    if (isOrientationHorizontal()) {
        mInitialMotionX = mLastMotionX = 0;
    } else {
        mInitialMotionY = mLastMotionY = 0;
    }
    if (mVelocityTracker == null) {
        mVelocityTracker = VelocityTracker.obtain();
    } else {
        mVelocityTracker.clear();
    }
    final long time = SystemClock.uptimeMillis();
    final MotionEvent ev = MotionEvent.obtain(time, time, MotionEvent.ACTION_DOWN, 0, 0, 0);
    mVelocityTracker.addMovement(ev);
    ev.recycle();
    mFakeDragBeginTime = time;
    return true;
}

---

From source file:android.improving.utils.views.cardsview.OrientedViewPager.java

/**
 * Start a fake drag of the pager./* www  . ja  va  2s.c  om*/
 * <p/>
 * <p>A fake drag can be useful if you want to synchronize the motion of the ViewPager
 * with the touch scrolling of another view, while still letting the ViewPager
 * control the snapping motion and fling behavior. (e.g. parallax-scrolling tabs.)
 * Call {@link #fakeDragBy(float)} to simulate the actual drag motion. Call
 * {@link #endFakeDrag()} to complete the fake drag and fling as necessary.
 * <p/>
 * <p>During a fake drag the ViewPager will ignore all touch events. If a real drag
 * is already in progress, this method will return false.
 *
 * @return true if the fake drag began successfully, false if it could not be started.
 * @see #fakeDragBy(float)
 * @see #endFakeDrag()
 */
public boolean beginFakeDrag() {
    if (mIsBeingDragged) {
        return false;
    }
    mFakeDragging = true;
    setScrollState(SCROLL_STATE_DRAGGING);
    if (mOrientation == Orientation.VERTICAL) {
        mInitialMotionY = mLastMotionY = 0;
    } else {
        mInitialMotionX = mLastMotionX = 0;
    }
    if (mVelocityTracker == null) {
        mVelocityTracker = VelocityTracker.obtain();
    } else {
        mVelocityTracker.clear();
    }
    final long time = SystemClock.uptimeMillis();
    final MotionEvent ev = MotionEvent.obtain(time, time, MotionEvent.ACTION_DOWN, 0, 0, 0);
    mVelocityTracker.addMovement(ev);
    ev.recycle();
    mFakeDragBeginTime = time;
    return true;
}

---

From source file:android.support.v71.widget.RecyclerView.java

@Override
public boolean onTouchEvent(MotionEvent e) {
    if (mLayoutFrozen || mIgnoreMotionEventTillDown) {
        return false;
    }//from   www.  j a  v  a2  s.c om
    if (dispatchOnItemTouch(e)) {
        cancelTouch();
        return true;
    }

    if (mLayout == null) {
        return false;
    }

    final boolean canScrollHorizontally = mLayout.canScrollHorizontally();
    final boolean canScrollVertically = mLayout.canScrollVertically();

    if (mVelocityTracker == null) {
        mVelocityTracker = VelocityTracker.obtain();
    }
    boolean eventAddedToVelocityTracker = false;

    final MotionEvent vtev = MotionEvent.obtain(e);
    final int action = MotionEventCompat.getActionMasked(e);
    final int actionIndex = MotionEventCompat.getActionIndex(e);

    if (action == MotionEvent.ACTION_DOWN) {
        mNestedOffsets[0] = mNestedOffsets[1] = 0;
    }
    vtev.offsetLocation(mNestedOffsets[0], mNestedOffsets[1]);

    switch (action) {
    case MotionEvent.ACTION_DOWN: {
        mScrollPointerId = MotionEventCompat.getPointerId(e, 0);
        mInitialTouchX = mLastTouchX = (int) (e.getX() + 0.5f);
        mInitialTouchY = mLastTouchY = (int) (e.getY() + 0.5f);

        int nestedScrollAxis = ViewCompat.SCROLL_AXIS_NONE;
        if (canScrollHorizontally) {
            nestedScrollAxis |= ViewCompat.SCROLL_AXIS_HORIZONTAL;
        }
        if (canScrollVertically) {
            nestedScrollAxis |= ViewCompat.SCROLL_AXIS_VERTICAL;
        }
        startNestedScroll(nestedScrollAxis);
    }
        break;

    case MotionEventCompat.ACTION_POINTER_DOWN: {
        mScrollPointerId = MotionEventCompat.getPointerId(e, actionIndex);
        mInitialTouchX = mLastTouchX = (int) (MotionEventCompat.getX(e, actionIndex) + 0.5f);
        mInitialTouchY = mLastTouchY = (int) (MotionEventCompat.getY(e, actionIndex) + 0.5f);
    }
        break;

    case MotionEvent.ACTION_MOVE: {
        final int index = MotionEventCompat.findPointerIndex(e, mScrollPointerId);
        if (index < 0) {
            Log.e(TAG, "Error processing scroll; pointer index for id " + mScrollPointerId
                    + " not found. Did any MotionEvents get skipped?");
            return false;
        }

        final int x = (int) (MotionEventCompat.getX(e, index) + 0.5f);
        final int y = (int) (MotionEventCompat.getY(e, index) + 0.5f);
        int dx = mLastTouchX - x;
        int dy = mLastTouchY - y;

        if (dispatchNestedPreScroll(dx, dy, mScrollConsumed, mScrollOffset)) {
            dx -= mScrollConsumed[0];
            dy -= mScrollConsumed[1];
            vtev.offsetLocation(mScrollOffset[0], mScrollOffset[1]);
            // Updated the nested offsets
            mNestedOffsets[0] += mScrollOffset[0];
            mNestedOffsets[1] += mScrollOffset[1];
        }

        if (mScrollState != SCROLL_STATE_DRAGGING) {
            boolean startScroll = false;
            if (canScrollHorizontally && Math.abs(dx) > mTouchSlop) {
                if (dx > 0) {
                    dx -= mTouchSlop;
                } else {
                    dx += mTouchSlop;
                }
                startScroll = true;
            }
            if (canScrollVertically && Math.abs(dy) > mTouchSlop) {
                if (dy > 0) {
                    dy -= mTouchSlop;
                } else {
                    dy += mTouchSlop;
                }
                startScroll = true;
            }
            if (startScroll) {
                setScrollState(SCROLL_STATE_DRAGGING);
            }
        }

        if (mScrollState == SCROLL_STATE_DRAGGING) {
            mLastTouchX = x - mScrollOffset[0];
            mLastTouchY = y - mScrollOffset[1];

            if (scrollByInternal(canScrollHorizontally ? dx : 0, canScrollVertically ? dy : 0, vtev)) {
                getParent().requestDisallowInterceptTouchEvent(true);
            }
        }
    }
        break;

    case MotionEventCompat.ACTION_POINTER_UP: {
        onPointerUp(e);
    }
        break;

    case MotionEvent.ACTION_UP: {
        mVelocityTracker.addMovement(vtev);
        eventAddedToVelocityTracker = true;
        mVelocityTracker.computeCurrentVelocity(1000, mMaxFlingVelocity);
        final float xvel = canScrollHorizontally
                ? -VelocityTrackerCompat.getXVelocity(mVelocityTracker, mScrollPointerId)
                : 0;
        final float yvel = canScrollVertically
                ? -VelocityTrackerCompat.getYVelocity(mVelocityTracker, mScrollPointerId)
                : 0;
        if (!((xvel != 0 || yvel != 0) && fling((int) xvel, (int) yvel))) {
            setScrollState(SCROLL_STATE_IDLE);
        }
        resetTouch();
    }
        break;

    case MotionEvent.ACTION_CANCEL: {
        cancelTouch();
    }
        break;
    }

    if (!eventAddedToVelocityTracker) {
        mVelocityTracker.addMovement(vtev);
    }
    vtev.recycle();

    return true;
}

---

From source file:com.viewpagerindicator.MyDirectionalViewPager.java

/**
 * Start a fake drag of the pager.// w w w. j  a  v a2s  . com
 *
 * <p>A fake drag can be useful if you want to synchronize the motion of the ViewPager
 * with the touch scrolling of another view, while still letting the ViewPager
 * control the snapping motion and fling behavior. (e.g. parallax-scrolling tabs.)
 * Call {@link #fakeDragBy(float)} to simulate the actual drag motion. Call
 * {@link #endFakeDrag()} to complete the fake drag and fling as necessary.
 *
 * <p>During a fake drag the ViewPager will ignore all touch events. If a real drag
 * is already in progress, this method will return false.
 *
 * @return true if the fake drag began successfully, false if it could not be started.
 *
 * @see #fakeDragBy(float)
 * @see #endFakeDrag()
 */
public boolean beginFakeDrag() {
    if (mIsBeingDragged) {
        return false;
    }
    mFakeDragging = true;
    setScrollState(SCROLL_STATE_DRAGGING);
    if (mOrientation == HORIZONTAL) {
        mInitialMotionX = mLastMotionX = 0;
    } else {
        mInitialMotionY = mLastMotionY = 0;
    }
    if (mVelocityTracker == null) {
        mVelocityTracker = VelocityTracker.obtain();
    } else {
        mVelocityTracker.clear();
    }
    final long time = SystemClock.uptimeMillis();
    final MotionEvent ev = MotionEvent.obtain(time, time, MotionEvent.ACTION_DOWN, 0, 0, 0);
    mVelocityTracker.addMovement(ev);
    ev.recycle();
    mFakeDragBeginTime = time;
    return true;
}

---

From source file:cn.ismartv.tvrecyclerview.widget.RecyclerView.java

@Override
public boolean onInterceptTouchEvent(MotionEvent e) {
    if (mLayoutFrozen) {
        // When layout is frozen,  RV does not intercept the motion event.
        // A child view e.g. a button may still get the click.
        return false;
    }/*from  www .  ja v  a2s  .c  o m*/
    if (dispatchOnItemTouchIntercept(e)) {
        cancelTouch();
        return true;
    }

    if (mLayout == null) {
        return false;
    }

    final boolean canScrollHorizontally = mLayout.canScrollHorizontally();
    final boolean canScrollVertically = mLayout.canScrollVertically();

    if (mVelocityTracker == null) {
        mVelocityTracker = VelocityTracker.obtain();
    }
    mVelocityTracker.addMovement(e);

    final int action = MotionEventCompat.getActionMasked(e);
    final int actionIndex = MotionEventCompat.getActionIndex(e);

    switch (action) {
    case MotionEvent.ACTION_DOWN:
        if (mIgnoreMotionEventTillDown) {
            mIgnoreMotionEventTillDown = false;
        }
        mScrollPointerId = e.getPointerId(0);
        mInitialTouchX = mLastTouchX = (int) (e.getX() + 0.5f);
        mInitialTouchY = mLastTouchY = (int) (e.getY() + 0.5f);

        if (mScrollState == SCROLL_STATE_SETTLING) {
            getParent().requestDisallowInterceptTouchEvent(true);
            setScrollState(SCROLL_STATE_DRAGGING);
        }

        // Clear the nested offsets
        mNestedOffsets[0] = mNestedOffsets[1] = 0;

        int nestedScrollAxis = ViewCompat.SCROLL_AXIS_NONE;
        if (canScrollHorizontally) {
            nestedScrollAxis |= ViewCompat.SCROLL_AXIS_HORIZONTAL;
        }
        if (canScrollVertically) {
            nestedScrollAxis |= ViewCompat.SCROLL_AXIS_VERTICAL;
        }
        startNestedScroll(nestedScrollAxis);
        break;

    case MotionEventCompat.ACTION_POINTER_DOWN:
        mScrollPointerId = e.getPointerId(actionIndex);
        mInitialTouchX = mLastTouchX = (int) (e.getX(actionIndex) + 0.5f);
        mInitialTouchY = mLastTouchY = (int) (e.getY(actionIndex) + 0.5f);
        break;

    case MotionEvent.ACTION_MOVE: {
        final int index = e.findPointerIndex(mScrollPointerId);
        if (index < 0) {
            Log.e(TAG, "Error processing scroll; pointer index for id " + mScrollPointerId
                    + " not found. Did any MotionEvents get skipped?");
            return false;
        }

        final int x = (int) (e.getX(index) + 0.5f);
        final int y = (int) (e.getY(index) + 0.5f);
        if (mScrollState != SCROLL_STATE_DRAGGING) {
            final int dx = x - mInitialTouchX;
            final int dy = y - mInitialTouchY;
            boolean startScroll = false;
            if (canScrollHorizontally && Math.abs(dx) > mTouchSlop) {
                mLastTouchX = mInitialTouchX + mTouchSlop * (dx < 0 ? -1 : 1);
                startScroll = true;
            }
            if (canScrollVertically && Math.abs(dy) > mTouchSlop) {
                mLastTouchY = mInitialTouchY + mTouchSlop * (dy < 0 ? -1 : 1);
                startScroll = true;
            }
            if (startScroll) {
                setScrollState(SCROLL_STATE_DRAGGING);
            }
        }
    }
        break;

    case MotionEventCompat.ACTION_POINTER_UP: {
        onPointerUp(e);
    }
        break;

    case MotionEvent.ACTION_UP: {
        mVelocityTracker.clear();
        stopNestedScroll();
    }
        break;

    case MotionEvent.ACTION_CANCEL: {
        cancelTouch();
    }
    }
    return mScrollState == SCROLL_STATE_DRAGGING;
}

---

From source file:cn.ismartv.tvrecyclerview.widget.RecyclerView.java

@Override
public boolean onTouchEvent(MotionEvent e) {
    if (mLayoutFrozen || mIgnoreMotionEventTillDown) {
        return false;
    }/* w  w  w .j a v  a2 s .  c  om*/
    if (dispatchOnItemTouch(e)) {
        cancelTouch();
        return true;
    }

    if (mLayout == null) {
        return false;
    }

    final boolean canScrollHorizontally = mLayout.canScrollHorizontally();
    final boolean canScrollVertically = mLayout.canScrollVertically();

    if (mVelocityTracker == null) {
        mVelocityTracker = VelocityTracker.obtain();
    }
    boolean eventAddedToVelocityTracker = false;

    final MotionEvent vtev = MotionEvent.obtain(e);
    final int action = MotionEventCompat.getActionMasked(e);
    final int actionIndex = MotionEventCompat.getActionIndex(e);

    if (action == MotionEvent.ACTION_DOWN) {
        mNestedOffsets[0] = mNestedOffsets[1] = 0;
    }
    vtev.offsetLocation(mNestedOffsets[0], mNestedOffsets[1]);

    switch (action) {
    case MotionEvent.ACTION_DOWN: {
        mScrollPointerId = e.getPointerId(0);
        mInitialTouchX = mLastTouchX = (int) (e.getX() + 0.5f);
        mInitialTouchY = mLastTouchY = (int) (e.getY() + 0.5f);

        int nestedScrollAxis = ViewCompat.SCROLL_AXIS_NONE;
        if (canScrollHorizontally) {
            nestedScrollAxis |= ViewCompat.SCROLL_AXIS_HORIZONTAL;
        }
        if (canScrollVertically) {
            nestedScrollAxis |= ViewCompat.SCROLL_AXIS_VERTICAL;
        }
        startNestedScroll(nestedScrollAxis);
    }
        break;

    case MotionEventCompat.ACTION_POINTER_DOWN: {
        mScrollPointerId = e.getPointerId(actionIndex);
        mInitialTouchX = mLastTouchX = (int) (e.getX(actionIndex) + 0.5f);
        mInitialTouchY = mLastTouchY = (int) (e.getY(actionIndex) + 0.5f);
    }
        break;

    case MotionEvent.ACTION_MOVE: {
        final int index = e.findPointerIndex(mScrollPointerId);
        if (index < 0) {
            Log.e(TAG, "Error processing scroll; pointer index for id " + mScrollPointerId
                    + " not found. Did any MotionEvents get skipped?");
            return false;
        }

        final int x = (int) (e.getX(index) + 0.5f);
        final int y = (int) (e.getY(index) + 0.5f);
        int dx = mLastTouchX - x;
        int dy = mLastTouchY - y;

        if (dispatchNestedPreScroll(dx, dy, mScrollConsumed, mScrollOffset)) {
            dx -= mScrollConsumed[0];
            dy -= mScrollConsumed[1];
            vtev.offsetLocation(mScrollOffset[0], mScrollOffset[1]);
            // Updated the nested offsets
            mNestedOffsets[0] += mScrollOffset[0];
            mNestedOffsets[1] += mScrollOffset[1];
        }

        if (mScrollState != SCROLL_STATE_DRAGGING) {
            boolean startScroll = false;
            if (canScrollHorizontally && Math.abs(dx) > mTouchSlop) {
                if (dx > 0) {
                    dx -= mTouchSlop;
                } else {
                    dx += mTouchSlop;
                }
                startScroll = true;
            }
            if (canScrollVertically && Math.abs(dy) > mTouchSlop) {
                if (dy > 0) {
                    dy -= mTouchSlop;
                } else {
                    dy += mTouchSlop;
                }
                startScroll = true;
            }
            if (startScroll) {
                setScrollState(SCROLL_STATE_DRAGGING);
            }
        }

        if (mScrollState == SCROLL_STATE_DRAGGING) {
            mLastTouchX = x - mScrollOffset[0];
            mLastTouchY = y - mScrollOffset[1];

            if (scrollByInternal(canScrollHorizontally ? dx : 0, canScrollVertically ? dy : 0, vtev)) {
                getParent().requestDisallowInterceptTouchEvent(true);
            }
        }
    }
        break;

    case MotionEventCompat.ACTION_POINTER_UP: {
        onPointerUp(e);
    }
        break;

    case MotionEvent.ACTION_UP: {
        mVelocityTracker.addMovement(vtev);
        eventAddedToVelocityTracker = true;
        mVelocityTracker.computeCurrentVelocity(1000, mMaxFlingVelocity);
        final float xvel = canScrollHorizontally
                ? -VelocityTrackerCompat.getXVelocity(mVelocityTracker, mScrollPointerId)
                : 0;
        final float yvel = canScrollVertically
                ? -VelocityTrackerCompat.getYVelocity(mVelocityTracker, mScrollPointerId)
                : 0;
        if (!((xvel != 0 || yvel != 0) && fling((int) xvel, (int) yvel))) {
            setScrollState(SCROLL_STATE_IDLE);
        }
        resetTouch();
    }
        break;

    case MotionEvent.ACTION_CANCEL: {
        cancelTouch();
    }
        break;
    }

    if (!eventAddedToVelocityTracker) {
        mVelocityTracker.addMovement(vtev);
    }
    vtev.recycle();

    return true;
}

---

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