Example usage for com.facebook.react.views.scroll ReactScrollViewHelper MOMENTUM_DELAY

Introduction

In this page you can find the example usage for com.facebook.react.views.scroll ReactScrollViewHelper MOMENTUM_DELAY.

Prototype

long MOMENTUM_DELAY

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Usage

From source file:com.rnnestedscrollview.ReactNestedScrollView.java

License:MIT License

/**
 * This handles any sort of scrolling that may occur after a touch is finished.  This may be
 * momentum scrolling (fling) or because you have pagingEnabled on the scroll view.  Because we
 * don't get any events from Android about this lifecycle, we do all our detection by creating a
 * runnable that checks if we scrolled in the last frame and if so assumes we are still scrolling.
 *///from   w w w  . j  av  a  2s  .co  m
private void handlePostTouchScrolling(int velocityX, int velocityY) {
    // If we aren't going to do anything (send events or snap to page), we can early exit out.
    if (!mSendMomentumEvents && !mPagingEnabled && !isScrollPerfLoggingEnabled()) {
        return;
    }

    // Check if we are already handling this which may occur if this is called by both the touch up
    // and a fling call
    if (mPostTouchRunnable != null) {
        return;
    }

    if (mSendMomentumEvents) {
        enableFpsListener();
        ReactScrollViewHelper.emitScrollMomentumBeginEvent(this, velocityX, velocityY);
    }

    mActivelyScrolling = false;
    mPostTouchRunnable = new Runnable() {

        private boolean mSnappingToPage = false;

        @Override
        public void run() {
            if (mActivelyScrolling) {
                // We are still scrolling so we just post to check again a frame later
                mActivelyScrolling = false;
                ViewCompat.postOnAnimationDelayed(ReactNestedScrollView.this, this,
                        ReactScrollViewHelper.MOMENTUM_DELAY);
            } else {
                if (mPagingEnabled && !mSnappingToPage) {
                    // Only if we have pagingEnabled and we have not snapped to the page do we
                    // need to continue checking for the scroll.  And we cause that scroll by asking for it
                    mSnappingToPage = true;
                    flingAndSnap(0);
                    ViewCompat.postOnAnimationDelayed(ReactNestedScrollView.this, this,
                            ReactScrollViewHelper.MOMENTUM_DELAY);
                } else {
                    if (mSendMomentumEvents) {
                        ReactScrollViewHelper.emitScrollMomentumEndEvent(ReactNestedScrollView.this);
                    }
                    ReactNestedScrollView.this.mPostTouchRunnable = null;
                    disableFpsListener();
                }
            }
        }
    };
    ViewCompat.postOnAnimationDelayed(ReactNestedScrollView.this, mPostTouchRunnable,
            ReactScrollViewHelper.MOMENTUM_DELAY);
}

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From source file:com.zulipmobile.AnchorScrollView.java

License:Open Source License

@Override
public void fling(int velocityY) {
    if (mScroller != null) {
        // FB SCROLLVIEW CHANGE

        // We provide our own version of fling that uses a different call to the standard OverScroller
        // which takes into account the possibility of adding new content while the ScrollView is
        // animating. Because we give essentially no max Y for the fling, the fling will continue as long
        // as there is content. See #onOverScrolled() to see the second part of this change which properly
        // aborts the scroller animation when we get to the bottom of the ScrollView content.

        int scrollWindowHeight = getHeight() - getPaddingBottom() - getPaddingTop();

        mScroller.fling(getScrollX(), getScrollY(), 0, velocityY, 0, 0, 0, Integer.MAX_VALUE, 0,
                scrollWindowHeight / 2);

        postInvalidateOnAnimation();//  w w w.ja va2s .  c  om

        // END FB SCROLLVIEW CHANGE
    } else {
        super.fling(velocityY);
    }

    if (mSendMomentumEvents || isScrollPerfLoggingEnabled()) {
        mFlinging = true;
        enableFpsListener();
        ReactScrollViewHelper.emitScrollMomentumBeginEvent(this);
        Runnable r = new Runnable() {
            @Override
            public void run() {
                if (mDoneFlinging) {
                    mFlinging = false;
                    disableFpsListener();
                    ReactScrollViewHelper.emitScrollMomentumEndEvent(AnchorScrollView.this);
                } else {
                    mDoneFlinging = true;
                    AnchorScrollView.this.postOnAnimationDelayed(this, ReactScrollViewHelper.MOMENTUM_DELAY);
                }
            }
        };
        postOnAnimationDelayed(r, ReactScrollViewHelper.MOMENTUM_DELAY);
    }
}

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