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

Introduction

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

Prototype

public static void emitScrollMomentumBeginEvent(ViewGroup scrollView, int xVelocity, int yVelocity) 

Source Link

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 www.j  a v  a  2  s  .c o 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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