@Override public int clampViewPositionVertical(final View child, final int top, final int dy) { final int current = mDrawer.getHeaderTop(); if (!Float.isNaN(mDx) && mDrawer.isValidScroll(mDx, dy)) { mScrollingHeaderByHelper = false; return current; } if (dy > 0 && mDrawer.canScrollCallback(-dy) && mDrawer.isTouchingScrollableContent()) { if (!mDrawer.isUsingDragHelper()) { // Scrolling up while list still has space to scroll, so make header still mScrollingHeaderByHelper = false; return current; } else { mDrawer.scrollByCallback(-dy); mScrollingHeaderByHelper = false; return current; } } final int min = mDrawer.getHeaderTopMinimum(), max = mDrawer.getHeaderTopMaximum(); if (top < min && mDrawer.isTouchingScrollableContent() && mDrawer.isUsingDragHelper()) { mDrawer.scrollByCallback(-dy); } mScrollingHeaderByHelper = true; return MathUtils.clamp(top, min, max); }
@Override public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) { if (!mDrawer.isUsingDragHelper() && mDrawer.isValidScroll(distanceY, distanceX)) { final int offset = mDrawer.getHeaderTop(), min = mDrawer.getHeaderTopMinimum(); if (!mDrawer.canScrollCallback(-1)) { if (distanceY < 0) { if (!mDrawer.isScrollingHeaderByHelper()) { mDrawer.offsetHeaderBy(Math.round(-distanceY)); } mDrawer.setScrollingHeaderByGesture(true); } else if (distanceY > 0 && offset > min) { // Scrolling up when scrolling to list top, so we cancel touch event and scrolling // header up mDrawer.cancelTouchCallback(); if (!mDrawer.isScrollingHeaderByHelper()) { mDrawer.offsetHeaderBy(Math.round(-distanceY)); } } else if (offset <= min) { mDrawer.scrollByCallback(-distanceX); } } } return true; }