@Override
public boolean onTouchEvent(MotionEvent ev) {
if (!mIsFlippingEnabled) {
return false;
}
if (mPageCount < 1) {
return false;
}
if (!mIsFlipping && !mLastTouchAllowed) {
return false;
}
final int action = ev.getAction();
if (action == MotionEvent.ACTION_UP
|| action == MotionEvent.ACTION_CANCEL
|| action == MotionEvent.ACTION_OUTSIDE) {
mLastTouchAllowed = false;
} else {
mLastTouchAllowed = true;
}
trackVelocity(ev);
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
// start flipping immediately if interrupting some sort of animation
if (endScroll() || endPeak()) {
mIsFlipping = true;
}
// Remember where the motion event started
mLastX = ev.getX();
mLastY = ev.getY();
mActivePointerId = MotionEventCompat.getPointerId(ev, 0);
mFlipDistanceDuringMotionDown = mFlipDistance;
break;
case MotionEvent.ACTION_MOVE:
if (!mIsFlipping) {
final int pointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId);
if (pointerIndex == -1) {
mActivePointerId = INVALID_POINTER;
break;
}
final float x = MotionEventCompat.getX(ev, pointerIndex);
final float xDiff = Math.abs(x - mLastX);
final float y = MotionEventCompat.getY(ev, pointerIndex);
final float yDiff = Math.abs(y - mLastY);
if ((mIsFlippingVertically && yDiff > mTouchSlop && yDiff > xDiff)
|| (!mIsFlippingVertically && xDiff > mTouchSlop && xDiff > yDiff)) {
mIsFlipping = true;
mLastX = x;
mLastY = y;
}
}
if (mIsFlipping) {
// Scroll to follow the motion event
final int activePointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId);
if (activePointerIndex == -1) {
mActivePointerId = INVALID_POINTER;
break;
}
final float x = MotionEventCompat.getX(ev, activePointerIndex);
final float deltaX = mLastX - x;
final float y = MotionEventCompat.getY(ev, activePointerIndex);
final float deltaY = mLastY - y;
mLastX = x;
mLastY = y;
float deltaFlipDistance = 0;
if (mIsFlippingVertically) {
deltaFlipDistance = deltaY;
} else {
deltaFlipDistance = deltaX;
}
deltaFlipDistance /=
((isFlippingVertically() ? getHeight() : getWidth()) / FLIP_DISTANCE_PER_PAGE);
mFlipDistance += deltaFlipDistance;
// This code block is used for, if you swipe from page N to page
// N+1, continue swiping will not trigger page N+2.
if (mFlipDistance - mFlipDistanceDuringMotionDown >= FLIP_DISTANCE_PER_PAGE) {
if (deltaFlipDistance > 0) {
// Undo.
mFlipDistance -= deltaFlipDistance;
}
} else if (mFlipDistance - mFlipDistanceDuringMotionDown <= -FLIP_DISTANCE_PER_PAGE) {
if (deltaFlipDistance < 0) {
// Undo.
mFlipDistance -= deltaFlipDistance;
}
}
final int minFlipDistance = 0;
final int maxFlipDistance = (mPageCount - 1) * FLIP_DISTANCE_PER_PAGE;
final boolean isOverFlipping =
mFlipDistance < minFlipDistance || mFlipDistance > maxFlipDistance;
if (isOverFlipping) {
mIsOverFlipping = true;
mFlipDistance = mOverFlipper.calculate(mFlipDistance, minFlipDistance, maxFlipDistance);
if (mOnOverFlipListener != null) {
float overFlip = mOverFlipper.getTotalOverFlip();
mOnOverFlipListener.onOverFlip(
this, mOverFlipMode, overFlip < 0, Math.abs(overFlip), FLIP_DISTANCE_PER_PAGE);
}
} else if (mIsOverFlipping) {
mIsOverFlipping = false;
if (mOnOverFlipListener != null) {
// TODO in the future should only notify flip distance 0
// on the correct edge (previous/next)
mOnOverFlipListener.onOverFlip(this, mOverFlipMode, false, 0, FLIP_DISTANCE_PER_PAGE);
mOnOverFlipListener.onOverFlip(this, mOverFlipMode, true, 0, FLIP_DISTANCE_PER_PAGE);
}
}
invalidate();
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
if (mIsFlipping) {
final VelocityTracker velocityTracker = mVelocityTracker;
velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
int velocity = 0;
if (isFlippingVertically()) {
velocity = (int) VelocityTrackerCompat.getYVelocity(velocityTracker, mActivePointerId);
} else {
velocity = (int) VelocityTrackerCompat.getXVelocity(velocityTracker, mActivePointerId);
}
smoothFlipTo(getNextPage(velocity));
mActivePointerId = INVALID_POINTER;
endFlip();
mOverFlipper.overFlipEnded();
}
break;
case MotionEventCompat.ACTION_POINTER_DOWN:
{
final int index = MotionEventCompat.getActionIndex(ev);
final float x = MotionEventCompat.getX(ev, index);
final float y = MotionEventCompat.getY(ev, index);
mLastX = x;
mLastY = y;
mActivePointerId = MotionEventCompat.getPointerId(ev, index);
break;
}
case MotionEventCompat.ACTION_POINTER_UP:
onSecondaryPointerUp(ev);
final int index = MotionEventCompat.findPointerIndex(ev, mActivePointerId);
final float x = MotionEventCompat.getX(ev, index);
final float y = MotionEventCompat.getY(ev, index);
mLastX = x;
mLastY = y;
break;
}
if (mActivePointerId == INVALID_POINTER) {
mLastTouchAllowed = false;
}
return true;
}
public void smoothFlipBy(int delta) {
smoothFlipTo(mCurrentPage + delta);
}